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Editor’s Choice Articles

Editor’s Choice articles are based on recommendations by the scientific editors of MDPI journals from around the world. Editors select a small number of articles recently published in the journal that they believe will be particularly interesting to readers, or important in the respective research area. The aim is to provide a snapshot of some of the most exciting work published in the various research areas of the journal.

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16 pages, 523 KiB  
Article
Soil Enzyme Activity Behavior after Urea Nitrogen Application
by Benjamin Davies, Jeffrey A. Coulter and Paulo H. Pagliari
Plants 2022, 11(17), 2247; https://doi.org/10.3390/plants11172247 - 29 Aug 2022
Cited by 10 | Viewed by 1923
Abstract
Understanding how fertilizer application (particularly N, the most used chemical fertilizer worldwide) interacts with soil microbes is important for the development of best management practices that target improved microbial activity to enhance sustainable food production. This study was conducted to determine whether urea [...] Read more.
Understanding how fertilizer application (particularly N, the most used chemical fertilizer worldwide) interacts with soil microbes is important for the development of best management practices that target improved microbial activity to enhance sustainable food production. This study was conducted to determine whether urea N rate and time of application to maize (Zea mays) influenced soil enzyme activity. Enzyme activity was determined by monitoring fluorescein diacetate (FDA) hydrolysis, ß-glucosidase, acid-phosphomonoesterase, and arylsulfatase activities. Experiments were conducted from 2014 through 2016 to compare single (fall or spring applications) and split applications of N at varying N rates under irrigation (Becker) and rainfed conditions (Lamberton and Waseca) in MN, USA. Nitrogen rates varied by location and were based on University of Minnesota guidelines. Soil samples were collected seven times each season. Nitrogen application split into two applications increased FDA activity by 10% compared with fall and spring applied N at Waseca. Fall or spring N application decreased arylsulfatase activity by 19% at Becker and by between 13% and 16% at Lamberton. ß-Glucosidase and acid-phosphomonoesterase activities were unaffected by N application. Sampling time and year had the greatest impact on enzyme activity, but the results varied by location. A negative linear relationship occurred between FDA and ß-glucosidase activity at all three sites. In summary, urea N application had small effects on enzyme activity at the sites studied, suggesting that some form of organic N could be more important than the ammonium provided by urea. Full article
(This article belongs to the Special Issue Current Soil-Health Status of Our Soils and Near-Term Trends on Potential Food Productivity)
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135 pages, 48870 KiB  
Review
A Revised Phylogenetic Classification for Viola (Violaceae)
by Thomas Marcussen, Harvey E. Ballard, Jiří Danihelka, Ana R. Flores, Marcela V. Nicola and John M. Watson
Plants 2022, 11(17), 2224; https://doi.org/10.3390/plants11172224 - 27 Aug 2022
Cited by 23 | Viewed by 8090
Abstract
The genus Viola (Violaceae) is among the 40–50 largest genera among angiosperms, yet its taxonomy has not been revised for nearly a century. In the most recent revision, by Wilhelm Becker in 1925, the then-known 400 species were distributed among 14 sections and [...] Read more.
The genus Viola (Violaceae) is among the 40–50 largest genera among angiosperms, yet its taxonomy has not been revised for nearly a century. In the most recent revision, by Wilhelm Becker in 1925, the then-known 400 species were distributed among 14 sections and numerous unranked groups. Here, we provide an updated, comprehensive classification of the genus, based on data from phylogeny, morphology, chromosome counts, and ploidy, and based on modern principles of monophyly. The revision is presented as an annotated global checklist of accepted species of Viola, an updated multigene phylogenetic network and an ITS phylogeny with denser taxon sampling, a brief summary of the taxonomic changes from Becker’s classification and their justification, a morphological binary key to the accepted subgenera, sections and subsections, and an account of each infrageneric subdivision with justifications for delimitation and rank including a description, a list of apomorphies, molecular phylogenies where possible or relevant, a distribution map, and a list of included species. We distribute the 664 species accepted by us into 2 subgenera, 31 sections, and 20 subsections. We erect one new subgenus of Viola (subg. Neoandinium, a replacement name for the illegitimate subg. Andinium), six new sections (sect. Abyssinium, sect. Himalayum, sect. Melvio, sect. Nematocaulon, sect. Spathulidium, sect. Xanthidium), and seven new subsections (subsect. Australasiaticae, subsect. Bulbosae, subsect. Clausenianae, subsect. Cleistogamae, subsect. Dispares, subsect. Formosanae, subsect. Pseudorupestres). Evolution within the genus is discussed in light of biogeography, the fossil record, morphology, and particular traits. Viola is among very few temperate and widespread genera that originated in South America. The biggest identified knowledge gaps for Viola concern the South American taxa, for which basic knowledge from phylogeny, chromosome counts, and fossil data is virtually absent. Viola has also never been subject to comprehensive anatomical study. Studies into seed anatomy and morphology are required to understand the fossil record of the genus. Full article
(This article belongs to the Special Issue Advances in Violaceae Research)
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18 pages, 3339 KiB  
Article
Quantity and Quality Changes in Sugar Beet (Beta vulgaris Provar. Altissima Doel) Induced by Different Sources of Biostimulants
by Marek Rašovský, Vladimír Pačuta, Ladislav Ducsay and Dominika Lenická
Plants 2022, 11(17), 2222; https://doi.org/10.3390/plants11172222 - 27 Aug 2022
Cited by 18 | Viewed by 2081
Abstract
The application of biostimulants in agriculture is considered an economically and ecologically acceptable and, above all, a sustainable method of cultivation of field crops. This study aimed to investigate the impact of biostimulating agents on the production and growth parameters of the sugar [...] Read more.
The application of biostimulants in agriculture is considered an economically and ecologically acceptable and, above all, a sustainable method of cultivation of field crops. This study aimed to investigate the impact of biostimulating agents on the production and growth parameters of the sugar beet. In 2018 and 2019, an experiment was conducted in which the effect of four types of treatment (B0–B3) on two varieties of sugar beet (Alpaca, Gorila) was observed. The results show that the beets treated with treatment type B3 (combination of humic acids, essential amino acids, biopolymers, and soil bacteria) had the significantly highest yield of roots compared with the control type. However, parameters such as sugar content, polarized sugar yield, white sugar content, and white sugar yield were the highest in condition B2, treated with an agent containing soil bacteria. Furthermore, biostimulants positively affected the leaf area index, with significant growth observed, especially in condition B3. Another important finding was that in the interaction analysis, the biostimulants had positive effects in dry conditions and on elevated values of traits of Alpaca variety caused by treatment in condition B2. In terms of relationships between individual parameters, an interesting finding was that there was only a weak relationship between root yield and sugar content (Rs = 0.0715), which indicates that biostimulants increase production size while maintaining or increasing its quality. Full article
(This article belongs to the Special Issue Advances in Strategies & Solutions against Abiotic Stresses in Crops under Climate Changes)
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13 pages, 1572 KiB  
Article
Pre- and Post-Harvest Conditions Affect Polyphenol Content in Strawberry (Fragaria × ananassa)
by Ryohei Koyama, Misaki Ishibashi, Itsuko Fukuda, Akitoshi Okino, Ro Osawa and Yuichi Uno
Plants 2022, 11(17), 2220; https://doi.org/10.3390/plants11172220 - 27 Aug 2022
Cited by 6 | Viewed by 2589
Abstract
The strawberry fruit contains abundant polyphenols, such as anthocyanins, flavan-3-ol, and ellagitannin. Polyphenol enrichment improves the quality of strawberries and leads to a better understanding of the polyphenol induction process. We measured the total polyphenol content of strawberry fruits under different growth conditions, [...] Read more.
The strawberry fruit contains abundant polyphenols, such as anthocyanins, flavan-3-ol, and ellagitannin. Polyphenol enrichment improves the quality of strawberries and leads to a better understanding of the polyphenol induction process. We measured the total polyphenol content of strawberry fruits under different growth conditions, developmental stages, and treatment conditions during pre-harvest and post-harvest periods. High fruit polyphenol content was observed in cold treatment, which was selected for further analysis and optimization. A transcriptome analysis of cold-treated fruits suggested that the candidate components of polyphenols may exist in the phenylpropanoid pathway. Coverage with a porous film bag excluded the effects of drought stress and produced polyphenol-rich strawberry fruits without affecting quality or quantity. The degree of stress was assessed using known stress indicators. A rapid accumulation of abscisic acid was followed by an increase in superoxide dismutase and DPPH (2,2-Diphenyl-1-picrylhydrazyl) activity, suggesting that the strawberry fruits responded to cold stress immediately, reaching the climax at around 6 days, a trend consistent with that of polyphenol content. These findings enhance our understanding of the mechanism of post-harvest polyphenol accumulation and the value of strawberries as a functional food. Full article
(This article belongs to the Special Issue Molecular Regulation of Fruit Ripening and Postharvest)
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14 pages, 5693 KiB  
Article
Optimization of the Extraction Procedure for the Phenolic-Rich Glechoma hederacea L. Herb and Evaluation of Its Cytotoxic and Antioxidant Potential
by Karolina Grabowska, Kinga Amanowicz, Paweł Paśko, Irma Podolak and Agnieszka Galanty
Plants 2022, 11(17), 2217; https://doi.org/10.3390/plants11172217 - 26 Aug 2022
Cited by 6 | Viewed by 2256
Abstract
The dried Glechoma hederacea L. herb has a long history of use in traditional medicine. Its therapeutic potential is related to the presence of phenolic compounds. To optimize extraction efficiency the effect of the use of different techniques (HRE—heat reflux extraction, I/ME—infusion combined [...] Read more.
The dried Glechoma hederacea L. herb has a long history of use in traditional medicine. Its therapeutic potential is related to the presence of phenolic compounds. To optimize extraction efficiency the effect of the use of different techniques (HRE—heat reflux extraction, I/ME—infusion combined with maceration, UE—sonication and SE—Soxhlet extraction), various solvents (water and ethanol) and processing time (15 min to 2 h) on phenolics content was investigated. The HPLC method was applied to determine and compare the content of phenolic acids (rosmarinic, chlorogenic, protocatechuic) and flavonoids (rutin, isoquercetin) in the extracts. Furthermore, the cytotoxic activity of the extracts was examined for the first time against human cancer and normal cells of skin origin (A375, HTB140, HaCaT) and gastrointestinal origin (Caco-2 and HT-29, HepG2). In addition, the antioxidant potential was evaluated using the DPPH and FRAP method. The I/ME-water and HRE/ethanol procedures turned out to be optimal for obtaining extracts of dried G. hederacea L. herb rich in bioactive phenolics. These extracts exhibited high antioxidant activity, correlated with the content of the compounds analyzed. Furthermore, the extracts of the dried Glechoma herb were not toxic to normal human cells, indicating its safe use both internally and externally. Full article
(This article belongs to the Special Issue Plant Extracts and Their Cytotoxic Activities)
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17 pages, 405 KiB  
Review
Assessing the Usefulness of Moringa oleifera Leaf Extract as a Biostimulant to Supplement Synthetic Fertilizers: A Review
by Chuene Victor Mashamaite, Bonga Lewis Ngcobo, Alen Manyevere, Isa Bertling and Olaniyi Amos Fawole
Plants 2022, 11(17), 2214; https://doi.org/10.3390/plants11172214 - 26 Aug 2022
Cited by 28 | Viewed by 8710
Abstract
The extensive use of synthetic chemical fertilizers is associated with environmental pollution and soil degradation. In addition, the high costs of these fertilizers necessitate the search for alternative, eco-friendly and safe natural sources of phytonutrients. The liquid extracted from moringa (Moringa oleifera [...] Read more.
The extensive use of synthetic chemical fertilizers is associated with environmental pollution and soil degradation. In addition, the high costs of these fertilizers necessitate the search for alternative, eco-friendly and safe natural sources of phytonutrients. The liquid extracted from moringa (Moringa oleifera Lam.) leaves has been used in agriculture to improve the growth and productivity of several crops. The efficacy of moringa leaf extract (MLE) is attributed to its high content of mineral nutrients, protein, vitamins, sugars, fiber, phenolics and free proline. In addition, MLE contains significant amounts of phytohormones, such as auxins, cytokinins and gibberellins. Furthermore, MLE is a valuable product promoting seed germination, plant growth and deeper root development, delaying fruit senescence and increasing the yield and quality of crops grown under normal or stressful conditions. Here, we review the research on MLE as a biostimulant to enhance crop growth and productivity. Moreover, we emphasize its possible introduction to smallholder farming systems to provide phytonutrients, and we further highlight research gaps in the existing knowledge regarding MLE application. Generally, MLE is an inexpensive, sustainable, eco-friendly and natural biostimulant that can be used to improve the growth and productivity attributes of various crops under non-stressful and stressful conditions. Full article
(This article belongs to the Special Issue Biostimulants as Growth Promoting and Stress Protecting Compounds)
26 pages, 7363 KiB  
Article
Reactivation of the Photosynthetic Apparatus of Resurrection Plant Haberlea rhodopensis during the Early Phase of Recovery from Drought- and Freezing-Induced Desiccation
by Gergana Mihailova, Nikolai K. Christov, Éva Sárvári, Ádám Solti, Richard Hembrom, Katalin Solymosi, Áron Keresztes, Maya Velitchkova, Antoaneta V. Popova, Lyudmila Simova-Stoilova, Elena Todorovska and Katya Georgieva
Plants 2022, 11(17), 2185; https://doi.org/10.3390/plants11172185 - 23 Aug 2022
Cited by 8 | Viewed by 2204
Abstract
Haberlea rhodopensis is a unique desiccation-tolerant angiosperm that also survives winter frost. As, upon freezing temperatures, H. rhodopensis desiccates, the taxon is proposed to survive low temperature stress using its desiccation tolerance mechanisms. To reveal the validity of this hypothesis, we analyzed the [...] Read more.
Haberlea rhodopensis is a unique desiccation-tolerant angiosperm that also survives winter frost. As, upon freezing temperatures, H. rhodopensis desiccates, the taxon is proposed to survive low temperature stress using its desiccation tolerance mechanisms. To reveal the validity of this hypothesis, we analyzed the structural alterations and organization of photosynthetic apparatus during the first hours of recovery after drought- and freezing-induced desiccation. The dynamics of the ultrastructure remodeling in the mesophyll cells and the restoration of the thylakoid membranes shared similarities independent of the reason for desiccation. Among the most obvious changes in thylakoid complexes, the proportion of the PSI-LHCII complex strongly increased around 70% relative water content (RWC), whereas the proportion of Lhc monomers decreased from the beginning of rehydration. We identified enhanced levels of cyt b6f complex proteins that contributed to the enhanced electron flow. The high abundance of proteins related to excitation energy dissipation, PsbS, Lhcb5, Lhcb6 and ELIPs, together with the increased content of dehydrins contributed to the preservation of cellular integrity. ELIP expression was maintained at high levels up to 9 h into recovery. Although the recovery processes from drought- and freezing-induced desiccation were found to be similar in progress and time scale, slight variations indicate that they are not identical. Full article
(This article belongs to the Section Plant Development and Morphogenesis)
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13 pages, 1909 KiB  
Review
To Be Seen or Not to Be Seen: Latent Infection by Tobamoviruses
by Rabia Ilyas, Mareike J. Rohde, Katja R. Richert-Pöggeler and Heiko Ziebell
Plants 2022, 11(16), 2166; https://doi.org/10.3390/plants11162166 - 21 Aug 2022
Cited by 15 | Viewed by 3552
Abstract
Tobamoviruses are among the most well-studied plant viruses and yet there is still a lot to uncover about them. On one side of the spectrum, there are damage-causing members of this genus: such as the tobacco mosaic virus (TMV), tomato brown rugose fruit [...] Read more.
Tobamoviruses are among the most well-studied plant viruses and yet there is still a lot to uncover about them. On one side of the spectrum, there are damage-causing members of this genus: such as the tobacco mosaic virus (TMV), tomato brown rugose fruit virus (ToBRFV) and cucumber green mottle mosaic virus (CGMMV), on the other side, there are members which cause latent infection in host plants. New technologies, such as high-throughput sequencing (HTS), have enabled us to discover viruses from asymptomatic plants, viruses in mixed infections where the disease etiology cannot be attributed to a single entity and more and more researchers a looking at non-crop plants to identify alternative virus reservoirs, leading to new virus discoveries. However, the diversity of these interactions in the virosphere and the involvement of multiple viruses in a single host is still relatively unclear. For such host–virus interactions in wild plants, symptoms are not always linked with the virus titer. In this review, we refer to latent infection as asymptomatic infection where plants do not suffer despite systemic infection. Molecular mechanisms related to latent behavior of tobamoviruses are unknown. We will review different studies which support different theories behind latency. Full article
(This article belongs to the Special Issue Tobamoviruses and Interacting Viruses in Modern Agriculture)
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16 pages, 6992 KiB  
Article
Climatic Factors Determine the Distribution Patterns of Leaf Nutrient Traits at Large Scales
by Xianxian Wang, Jiangfeng Wang, Liuyang Zhang, Chengyu Lv, Longlong Liu, Huixin Zhao and Jie Gao
Plants 2022, 11(16), 2171; https://doi.org/10.3390/plants11162171 - 21 Aug 2022
Cited by 9 | Viewed by 1702
Abstract
Leaf nutrient content and its stoichiometric relationships (N/P ratio) are essential for photosynthesis and plant growth and development. Previous studies on leaf nutrient-related functional traits have mainly focused on the species level and regional scale, but fewer studies have investigated the distribution patterns [...] Read more.
Leaf nutrient content and its stoichiometric relationships (N/P ratio) are essential for photosynthesis and plant growth and development. Previous studies on leaf nutrient-related functional traits have mainly focused on the species level and regional scale, but fewer studies have investigated the distribution patterns of the leaf N and P contents (LN, LP) and N/P ratios (N/P) in communities and their controlling factors at a large scale; therefore, we used LN, LP, and N/P data at 69 sites from 818 forests in China. The results showed significant differences (p < 0.05) in the LN, LP, and N/P at different life forms (tree, shrub, and herb). Neither LN, LP, nor N/P ratios showed significant patterns of latitudinal variation. With the increase in temperature and rainfall, the LN, LP, and leaf nutrient contents increased significantly (p < 0.001). Across life forms, LN at different life forms varied significantly and was positively correlated with soil P content (p < 0.001). The explanatory degree of climatic factors in shaping the spatial variation patterns of LN and N/P was higher than that of the soil nutrient factors, and the spatial variation patterns of the leaf nutrient traits of different life forms were shaped by the synergistic effects of climatic factors and soil nutrient factors. Full article
(This article belongs to the Special Issue Plant Morphology and Function, Geometric Morphometrics, and Modelling: Decoding the Mathematical Secrets of Plants)
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12 pages, 1638 KiB  
Article
β-Cyclocitral Does Not Contribute to Singlet Oxygen-Signalling in Algae, but May Down-Regulate Chlorophyll Synthesis
by Thomas Roach, Theresa Baur and Ilse Kranner
Plants 2022, 11(16), 2155; https://doi.org/10.3390/plants11162155 - 19 Aug 2022
Cited by 5 | Viewed by 1862
Abstract
Light stress signalling in algae and plants is partially orchestrated by singlet oxygen (1O2), a reactive oxygen species (ROS) that causes significant damage within the chloroplast, such as lipid peroxidation. In the vicinity of the photosystem II reaction centre, [...] Read more.
Light stress signalling in algae and plants is partially orchestrated by singlet oxygen (1O2), a reactive oxygen species (ROS) that causes significant damage within the chloroplast, such as lipid peroxidation. In the vicinity of the photosystem II reaction centre, a major source of 1O2, are two β-carotene molecules that quench 1O2 to ground-state oxygen. 1O2 can oxidise β-carotene to release β-cyclocitral, which has emerged as a 1O2-mediated stress signal in the plant Arabidopsis thaliana. We investigated if β-cyclocitral can have similar retrograde signalling properties in the unicellular alga Chlamydomonas reinhardtii. Using RNA-Seq, we show that genes up-regulated in response to exogenous β-cyclocitral included CAROTENOID CLEAVAGE DIOXYGENASE 8 (CCD8), while down-regulated genes included those associated with porphyrin and chlorophyll anabolism, such as tetrapyrrole-binding protein (GUN4), magnesium chelatases (CHLI1, CHLI2, CHLD, CHLH1), light-dependent protochlorophyllide reductase (POR1), copper target 1 protein (CTH1), and coproporphyrinogen III oxidase (CPX1). Down-regulation of this pathway has also been shown in β-cyclocitral-treated A. thaliana, indicating conservation of this signalling mechanism in plants. However, in contrast to A. thaliana, a very limited overlap in differential gene expression was found in β-cyclocitral-treated and 1O2-treated C. reinhardtii. Furthermore, exogenous treatment with β-cyclocitral did not induce tolerance to 1O2. We conclude that while β-cyclocitral may down-regulate chlorophyll synthesis, it does not seem to contribute to 1O2-mediated high light stress signalling in algae. Full article
(This article belongs to the Special Issue 10th Anniversary of Plants—Recent Advances and Perspectives)
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13 pages, 1821 KiB  
Review
Interaction of Ginseng with Ilyonectria Root Rot Pathogens
by Isadora Bischoff Nunes and Paul H. Goodwin
Plants 2022, 11(16), 2152; https://doi.org/10.3390/plants11162152 - 19 Aug 2022
Cited by 11 | Viewed by 2195
Abstract
The Ilyonectria radicicola species complex (A.A. Hildebr.) A. Cabral and Crous 2011 contains species of soilborne necrotrophic plant pathogens. The most aggressive to ginseng roots is I. mors-panacis, whereas I. robusta, I. crassa, I. panacis and I. radicicola are less [...] Read more.
The Ilyonectria radicicola species complex (A.A. Hildebr.) A. Cabral and Crous 2011 contains species of soilborne necrotrophic plant pathogens. The most aggressive to ginseng roots is I. mors-panacis, whereas I. robusta, I. crassa, I. panacis and I. radicicola are less aggressive. Infected ginseng roots show orange-red to black-brown lesions that can expand into a severe root rot, known as disappearing root rot, where only epidermal root tissue remains. Leaves become red-brown with wilting, and stems can have vascular discoloration with black-brown lesions at the base. Less aggressive Ilyonectria species trigger jasmonic acid (JA)-related defenses inducing host ginsenosides, pathogenesis-related (PR) proteins, wound periderm, and cell wall thickening. In contrast, I. mors-panacis triggers reactive oxygen species (ROS) and salicylic acid (SA) production but suppresses JA-related defenses and ginsenoside accumulation. It is also able to suppress SA-related PR protein production. Virulence factors include potential effectors that may suppress PAMP (Pathogen Associated Molecular Patterns) triggered immunity (PTI), polyphenoloxidases, Hsp90 inhibitors, siderophores and cell-wall-degrading enzymes, such as pectinases. Overall, I. mors-panacis appears to be more aggressive because it can suppress JA and SA-related PTI allowing for more extensive colonization of ginseng roots. While many possible mechanisms of host resistance and pathogen virulence mechanisms have been examined, there is a need for using genetic approaches, such as RNAi silencing of genes of Panax or Ilyonectria, to determine their importance in the interaction. Full article
(This article belongs to the Special Issue Fungus and Plant Interactions)
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15 pages, 3524 KiB  
Article
Cultivar and Postharvest Storage Duration Influence Fruit Quality, Nutritional and Phytochemical Profiles of Soilless-Grown Cantaloupe and Honeydew Melons
by Boitshepo L. Pulela, Martin M. Maboko, Puffy Soundy and Stephen O. Amoo
Plants 2022, 11(16), 2136; https://doi.org/10.3390/plants11162136 - 17 Aug 2022
Cited by 8 | Viewed by 1990
Abstract
There is an increasing demand for sweet melon (Cucumis melo L.) fruit in fruit and vegetable markets due to its nutritional content, resulting in different cultivars being grown in different production systems. This study evaluated the nutritional and phytochemical contents of soilless-grown [...] Read more.
There is an increasing demand for sweet melon (Cucumis melo L.) fruit in fruit and vegetable markets due to its nutritional content, resulting in different cultivars being grown in different production systems. This study evaluated the nutritional and phytochemical contents of soilless-grown cantaloupe and honeydew sweet melon cultivars at harvest and postharvest. At harvest, vitamin C and β-carotene concentrations were higher in orange-fleshed (cantaloupe) cvs. Magritte, Divine, Majestic, Cyclone, MAB 79001, E25F.00185, E25F.00075 and Adore, compared to green-fleshed (honeydew) cvs. Honey Brew and Honey Star. The zinc (Zn), phosphorus (P), potassium (K), magnesium (Mg) and calcium (Ca) contents were higher in orange-fleshed compared to green-fleshed cultivars. Total phenolics content (TPC) in cv. E25F.00075 was the highest (2.87 mg GAE∙g−1 dry weight). A significant, positive, correlation occurred between β-carotene and Zn, P, K, Ca and Mg contents. Postharvest storage duration affected TPC and total soluble solid content. The interaction of cultivar and postharvest storage duration affected flavonoid, vitamin C and β-carotene contents, free radical scavenging activity and fruit juice pH. Vitamin C and β-carotene contents decreased with increased postharvest storage duration while flavonoid content increased. The cantaloupe cultivars performed significantly better compared to the honeydew cultivars as evident in their high mineral element content, and vitamin C and β-carotene concentrations. Selection of appropriate cultivars in a production system should consider variation in nutritional traits of cultivars and postharvest storage duration. Soilless production of sweet melon cultivars in tunnels offers a viable alternative to open field to produce high-quality melons at harvest and postharvest. Full article
(This article belongs to the Special Issue Vegetable and Fruit Production)
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17 pages, 3502 KiB  
Article
Phytochemical Screening, Antioxidant and Antibacterial Properties of Extracts of Viscum continuum E. Mey. Ex Sprague, a South African Mistletoe
by Sipho Mapfumari, Noel-David Nogbou, Andrew Musyoki, Stanley Gololo, Mmamosheledi Mothibe and Kokoette Bassey
Plants 2022, 11(16), 2094; https://doi.org/10.3390/plants11162094 - 12 Aug 2022
Cited by 9 | Viewed by 4374
Abstract
Viscum continuum E. Mey. Ex Sprague is a woody evergreen semi-parasitic shrub that grows on the branches of other trees. It is used by African traditional healers for post-stroke management. This study reports on the qualitative phytochemical screening and the antioxidant and antimicrobial [...] Read more.
Viscum continuum E. Mey. Ex Sprague is a woody evergreen semi-parasitic shrub that grows on the branches of other trees. It is used by African traditional healers for post-stroke management. This study reports on the qualitative phytochemical screening and the antioxidant and antimicrobial activities of Viscum continuum’s acetone, methanol, hexane and dichloromethane extracts. Standard protocols for the phytochemical screening of extracts were employed. TLC bio-autography was used for qualitative antioxidants analysis. Assays: 2,2-diphenyl-1-picrylhydrazyl, H2O2 free-radical scavenging and ferric chloride reducing power were carried out for quantitative antioxidant analysis. The antimicrobial potential of extracts was screened using disc diffusion, bio-autography and broth micro-dilution. The results indicate the presence of alkaloids, phenolics and tannins in all extracts. Acetone and methanol revealed significant amount of saponins, phenolics, tannins and terpenoids. The extracts exhibited significant antioxidant potential on TLC with positive compound bands at an Rf range of 0.05–0.89. DPPH, H2O2 and the reduction of Fe3+ to Fe2+ assays indicated that methanol extract has a strong antioxidant potential, followed by acetone, DCM and lastly hexane. The extracts of Viscum continuum show the potential to be antibacterial agents. It can be concluded that Viscum continuum extracts contain phytochemicals which are capable of mitigating against chronic health conditions such as cancer, stroke and stress-related and infectious diseases. Full article
(This article belongs to the Special Issue Nutraceuticals and Biological Activity of Medicinal and Food Plants on Improving Human Well Being)
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16 pages, 2420 KiB  
Article
Genomic Insights into Cultivated Mexican Vanilla planifolia Reveal High Levels of Heterozygosity Stemming from Hybridization
by Paige Ellestad, Miguel Angel Pérez-Farrera and Sven Buerki
Plants 2022, 11(16), 2090; https://doi.org/10.3390/plants11162090 - 11 Aug 2022
Cited by 7 | Viewed by 2043
Abstract
Although vanilla is one of the most valuable spices, there is a lack of understanding of the genomic variability of the main vanilla producing species, Vanilla planifolia, within its cultivated origin, Mexico. High genomic heterozygosity levels within the globally cultivated ‘Daphna’ genome have [...] Read more.
Although vanilla is one of the most valuable spices, there is a lack of understanding of the genomic variability of the main vanilla producing species, Vanilla planifolia, within its cultivated origin, Mexico. High genomic heterozygosity levels within the globally cultivated ‘Daphna’ genome have raised questions on the possibility of a hybrid origin and analogous genomic signatures of vanilla cultivated within its origin. This study investigated these questions by assessing whether the genomic structure of Mexican V. planifolia reflected domestication events. Whole genome re-sequencing was used to compare genome complexity between 15 cultivated accessions from different regions and gene pools. Results showed high levels of heterozygosity, ranging from 2.48% to 2.85%, in all but one accession, which exhibited a low level (0.403%). Chromosome-level comparative analyses revealed genomic variability among samples, but no signals of chromosome rearrangements. These findings support the hypotheses that cultivated vanilla resulted from hybridization and that multiple domestication events have shaped cultivated vanilla leading to the formation of landraces. High cultural diversity within this region further supports the occurrence of multiple domestication processes. These results may help to improve breeding and conservation efforts aiming to preserve the genetic diversity of this beloved spice threatened by climate change. Full article
(This article belongs to the Special Issue Harnessing Crop Diversity through Genetics, Genomics and Phenomics Approaches)
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18 pages, 688 KiB  
Article
Traditional Uses of Medicinal Plants in South-Western Part of Lithuania
by Birutė Karpavičienė
Plants 2022, 11(16), 2093; https://doi.org/10.3390/plants11162093 - 11 Aug 2022
Cited by 6 | Viewed by 2024
Abstract
Changes in people’s dependence on the resources of the immediate natural environment and in the ways in which information is transmitted may result in the loss of some of the traditional knowledge of plants and their uses. In order to investigate and preserve [...] Read more.
Changes in people’s dependence on the resources of the immediate natural environment and in the ways in which information is transmitted may result in the loss of some of the traditional knowledge of plants and their uses. In order to investigate and preserve this knowledge, a comprehensive ethnobotanical study was carried out in a little-studied ethnographic region. Knowledge about the plants used for treatment was collected through open-ended and semi-structured interviews in villages and small rural settlements in southwestern Lithuania. In total, 30 informants reported 103 plant and 1 lichen species. Although the survey was carried out in a small area, up to five local names per species were recorded. The most frequently used species were Matricaria chamomilla, Tilia cordata, Artemisia absinthium and Plantago major. The largest number of plant species was used to treat digestive and respiratory system disorders. Wild plants were mentioned in 71.0% of all use reports, while a relatively higher proportion of cultivated plants was recorded among the new uses. Decoction and infusion were the most commonly used, while some unusual preparations have been recorded in past uses. Research showed that the diversity of plant species used for healing has declined over the last 20 years and that part of traditional ethnobotanical knowledge is disappearing. Full article
(This article belongs to the Special Issue Natural Resources of Berry and Medicinal Plants Volume II)
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17 pages, 2646 KiB  
Article
Transcriptome Analysis Reveals the Stress Tolerance to and Accumulation Mechanisms of Cadmium in Paspalum vaginatum Swartz
by Lei Xu, Yuying Zheng, Qing Yu, Jun Liu, Zhimin Yang and Yu Chen
Plants 2022, 11(16), 2078; https://doi.org/10.3390/plants11162078 - 9 Aug 2022
Cited by 10 | Viewed by 1709
Abstract
Cadmium (Cd) is a non-essential heavy metal and high concentrations in plants causes toxicity of their edible parts and acts as a carcinogen to humans and animals. Paspalum vaginatum is widely cultivating as turfgrass due to its higher abiotic stress tolerance ability. However, [...] Read more.
Cadmium (Cd) is a non-essential heavy metal and high concentrations in plants causes toxicity of their edible parts and acts as a carcinogen to humans and animals. Paspalum vaginatum is widely cultivating as turfgrass due to its higher abiotic stress tolerance ability. However, there is no clear evidence to elucidate the mechanism for heavy metal tolerance, including Cd. In this study, an RNA sequencing technique was employed to investigate the key genes associated with Cd stress tolerance and accumulation in P. vaginatum. The results revealed that antioxidant enzyme activities catalase (CAT), peroxidase (POD), superoxide dismutase (SOD), and glutathione S-transferase GST) were significantly higher at 24 h than in other treatments. A total of 6820 (4457/2363, up-/down-regulated), 14,038 (9894/4144, up-/down-regulated) and 17,327 (7956/9371, up-/down-regulated) differentially expressed genes (DEGs) between the Cd1 vs. Cd0, Cd4 vs. Cd0, and Cd24 vs. Cd0, respectively, were identified. The GO analysis and the KEGG pathway enrichment analysis showed that DEGs participated in many significant pathways in response to Cd stress. The response to abiotic stimulus, the metal transport mechanism, glutathione metabolism, and the consistency of transcription factor activity were among the most enriched pathways. The validation of gene expression by qRT-PCR results showed that heavy metal transporters and signaling response genes were significantly enriched with increasing sampling intervals, presenting consistency to the transcriptome data. Furthermore, over-expression of PvSnRK2.7 can positively regulate Cd-tolerance in Arabidopsis. In conclusion, our results provided a novel molecular mechanism of the Cd stress tolerance of P. vaginatum and will lay the foundation for target breeding of Cd tolerance in turfgrass. Full article
(This article belongs to the Special Issue Stress Biology of Turfgrass)
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19 pages, 4200 KiB  
Article
Identification of Soil Properties Associated with the Incidence of Banana Wilt Using Supervised Methods
by Barlin O. Olivares, Andrés Vega, María A. Rueda Calderón, Juan C. Rey, Deyanira Lobo, José A. Gómez and Blanca B. Landa
Plants 2022, 11(15), 2070; https://doi.org/10.3390/plants11152070 - 8 Aug 2022
Cited by 21 | Viewed by 3190
Abstract
Over the last few decades, a growing incidence of Banana Wilt (BW) has been detected in the banana-producing areas of the central zone of Venezuela. This disease is thought to be caused by a fungal–bacterial complex, coupled with the influence of specific soil [...] Read more.
Over the last few decades, a growing incidence of Banana Wilt (BW) has been detected in the banana-producing areas of the central zone of Venezuela. This disease is thought to be caused by a fungal–bacterial complex, coupled with the influence of specific soil properties. However, until now, there was no consensus on the soil characteristics associated with a high incidence of BW. The objective of this study was to identify the soil properties potentially associated with BW incidence, using supervised methods. The soil samples associated with banana plant lots in Venezuela, showing low (n = 29) and high (n = 49) incidence of BW, were collected during two consecutive years (2016 and 2017). On those soils, sixteen soil variables, including the percentage of sand, silt and clay, pH, electrical conductivity, organic matter, available contents of K, Na, Mg, Ca, Mn, Fe, Zn, Cu, S and P, were determined. The Wilcoxon test identified the occurrence of significant differences in the soil variables between the two groups of BW incidence. In addition, Orthogonal Least Squares Discriminant Analysis (OPLS-DA) and the Random Forest (RF) algorithm was applied to find soil variables capable of distinguishing banana lots showing high or low BW incidence. The OPLS-DA model showed a proper fitting of the data (R2Y: 0.61, p value < 0.01), and exhibited good predictive power (Q2: 0.50, p value < 0.01). The analysis of the Receiver Operating Characteristics (ROC) curves by RF revealed that the combination of Zn, Fe, Ca, K, Mn and Clay was able to accurately differentiate 84.1% of the banana lots with a sensitivity of 89.80% and a specificity of 72.40%. So far, this is the first study that identifies these six soil variables as possible new indicators associated with BW incidence in soils of lacustrine origin in Venezuela. Full article
(This article belongs to the Special Issue Integrated Disease Management in Fruit Crops)
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14 pages, 3681 KiB  
Article
Polyphenolic Contents, Free Radical Scavenging and Cholinesterase Inhibitory Activities of Dalbergiella welwitschii Leaf Extracts
by Tabisa Diniso, Jerry Adeyemi, Ayodeji Oriola, Taiwo Elufioye, Mavuto Gondwe and Adebola Oyedeji
Plants 2022, 11(15), 2066; https://doi.org/10.3390/plants11152066 - 8 Aug 2022
Cited by 5 | Viewed by 1656
Abstract
A decoction of Dalbergiella welwitschii leaves has been used ethnomedicinally for the treatment of mental illness and inflammatory diseases amongst other diseases. In this study, the leaf methanol extract of D. welwitschii and its partition fractions: n-hexane, ethyl acetate and aqueous, were tested [...] Read more.
A decoction of Dalbergiella welwitschii leaves has been used ethnomedicinally for the treatment of mental illness and inflammatory diseases amongst other diseases. In this study, the leaf methanol extract of D. welwitschii and its partition fractions: n-hexane, ethyl acetate and aqueous, were tested and evaluated for their polyphenolic contents, free radical scavenging and cholinesterase inhibitory activities. The total phenolic (TPC), flavonoid (TFC) and proanthocyanidin (TPA) contents were determined using standard colorimetric methods. The anti-radical activity of the extracts against the 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric ion and nitric oxide (NO) radicals as well as their effects on lipid peroxidation were monitored spectrophotometrically. The cholinesterase enzyme (AChE and BuChE) inhibitions by the extracts were determined by a modified method of Ellman. The result showed a concentration-dependent increase in inhibition of the free radicals and the cholinesterase enzymes, except for that of lipid peroxidation. The ethyl acetate (EtOAc) fraction exhibited the highest polyphenolic contents among the fractions, with a TPC of 1.08 mgGAE/g, TFC of 0.38 mgQuE/g and TPA of 0.21 mgGAE/g. It also demonstrated the highest free radical scavenging activities with 72.63% and 65.43% inhibitions of DPPH and NO, respectively. The EtOAc fraction inhibited AChE and BuChE enzymes with IC50 values of 0.94 and 8.49 mg/mL, respectively. Our findings show that the plant may have polyphenol contents, in particular in the methanol extract and EtOAc fraction. These extracts showed considerable free radical scavenging and cholinesterase inhibitory properties. Thus, the observed bioactivities may serve as a justification for its folkloric use as a remedy for mental illness. The study also provides relevant information that could help in the search for lead cholinesterase inhibitors from medicinal plants that can be exploited against neurodegenerative disorders. Full article
(This article belongs to the Special Issue Phenolic Composition and Antioxidant Activity of Plant Extracts Ⅱ)
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15 pages, 2827 KiB  
Article
Marker-Trait Associations for Total Carotenoid Content and Individual Carotenoids in Durum Wheat Identified by Genome-Wide Association Analysis
by María Dolores Requena-Ramírez, Cristina Rodríguez-Suárez, Fernando Flores, Dámaso Hornero-Méndez and Sergio G. Atienza
Plants 2022, 11(15), 2065; https://doi.org/10.3390/plants11152065 - 7 Aug 2022
Cited by 4 | Viewed by 1884
Abstract
Yellow pigment content is one of the main traits considered for grain quality in durum wheat (Triticum turgidum L.). The yellow color is mostly determined by carotenoid pigments, lutein being the most abundant in wheat endosperm, although zeaxanthin, α-carotene and β-carotene are [...] Read more.
Yellow pigment content is one of the main traits considered for grain quality in durum wheat (Triticum turgidum L.). The yellow color is mostly determined by carotenoid pigments, lutein being the most abundant in wheat endosperm, although zeaxanthin, α-carotene and β-carotene are present in minor quantities. Due to the importance of carotenoids in human health and grain quality, modifying the carotenoid content and profile has been a classic target. Landraces are then a potential source for the variability needed for wheat breeding. In this work, 158 accessions of the Spanish durum wheat collection were characterized for carotenoid content and profile and genotyped using the DArTSeq platform for association analysis. A total of 28 marker-trait associations were identified and their co-location with previously described QTLs and candidate genes was studied. The results obtained confirm the importance of the widely described QTL in 7B and validate the QTL regions recently identified by haplotype analysis for the semolina pigment. Additionally, copies of the Zds and Psy genes on chromosomes 7B and 5B, respectively, may have a putative role in determining zeaxanthin content. Finally, genes for the methylerythritol 4-phosphate (MEP) and isopentenyl diphosphate (IPPI) carotenoid precursor pathways were revealed as additional sources of untapped variation for carotenoid improvement. Full article
(This article belongs to the Section Plant Molecular Biology)
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16 pages, 3110 KiB  
Article
Impact of Storage Condition on Chemical Composition and Antifungal Activity of Pomelo Extract against Colletotrichum gloeosporioides and Anthracnose in Post-harvest Mango
by Yu-Jung Cheng, Ying-Jou Wu, Fang-Wei Lee, Ling-Yi Ou, Chi-Nan Chen, Yu-Ying Chu and Yen-Chou Kuan
Plants 2022, 11(15), 2064; https://doi.org/10.3390/plants11152064 - 7 Aug 2022
Cited by 13 | Viewed by 2786
Abstract
Anthracnose caused by Colletotrichum leads to a tremendous post-harvest mango loss. While chemical fungicides are applied to control anthracnose, natural alternatives are preferred due to food safety and environmental concerns. Pomelo extract (PE) exhibits a broad spectrum of antimicrobial activities; however, its effect [...] Read more.
Anthracnose caused by Colletotrichum leads to a tremendous post-harvest mango loss. While chemical fungicides are applied to control anthracnose, natural alternatives are preferred due to food safety and environmental concerns. Pomelo extract (PE) exhibits a broad spectrum of antimicrobial activities; however, its effect against anthracnose is unknown. Here we investigated the chemical profile of PE using GC-MS and the anti-anthracnose activity of PE using in vitro and in vivo assays. We also evaluated the impact of storage temperature (0°, 5°, 10°, 20°, −20°, and −80 °C) and light conditions on the composition and antifungal activity of PE. We found that PE inhibited C. gloeosporioides in vitro with an IC50 of 3.2 mL L−1. Applying chitosan-based coating incorporated with 20 mL L−1 PE significantly suppressed anthracnose in post-harvest ‘Keitt’ mango. A storage temperature below 5 °C substantially preserved major compounds and the antifungal activity of PE after 6 m of storage. Finally, we showed that applying d-limonene, the key constituent of PE, inhibited C. gloeosporioides in vitro (IC50: 10.9 mM) and suppressed anthracnose in vivo. In conclusion, we demonstrated that the application of PE and d-limonene are sustainable methods for anthracnose control in post-harvest crops and established the preservation protocol for PE. Full article
(This article belongs to the Special Issue Emerging Technologies for Reducing Postharvest Loss of Fruits and Vegetables)
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36 pages, 1224 KiB  
Review
Advanced Breeding for Biotic Stress Resistance in Poplar
by Chiara Biselli, Lorenzo Vietto, Laura Rosso, Luigi Cattivelli, Giuseppe Nervo and Agostino Fricano
Plants 2022, 11(15), 2032; https://doi.org/10.3390/plants11152032 - 4 Aug 2022
Cited by 16 | Viewed by 2749
Abstract
Poplar is one of the most important forest trees because of its high economic value. Thanks to the fast-growing rate, easy vegetative propagation and transformation, and availability of genomic resources, poplar has been considered the model species for forest genetics, genomics, and breeding. [...] Read more.
Poplar is one of the most important forest trees because of its high economic value. Thanks to the fast-growing rate, easy vegetative propagation and transformation, and availability of genomic resources, poplar has been considered the model species for forest genetics, genomics, and breeding. Being a field-growing tree, poplar is exposed to environmental threats, including biotic stresses that are becoming more intense and diffused because of global warming. Current poplar farming is mainly based on monocultures of a few elite clones and the expensive and long-term conventional breeding programmes of perennial tree species cannot face current climate-change challenges. Consequently, new tools and methods are necessary to reduce the limits of traditional breeding related to the long generation time and to discover new sources of resistance. Recent advances in genomics, marker-assisted selection, genomic prediction, and genome editing offer powerful tools to efficiently exploit the Populus genetic diversity and allow enabling molecular breeding to support accurate early selection, increasing the efficiency, and reducing the time and costs of poplar breeding, that, in turn, will improve our capacity to face or prevent the emergence of new diseases or pests. Full article
(This article belongs to the Special Issue Poplar Responses to Environmental Stresses)
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15 pages, 2197 KiB  
Article
Morpho-Anatomical, Physiological, and Mineral Composition Responses Induced by a Vegetal-Based Biostimulant at Three Rates of Foliar Application in Greenhouse Lettuce
by Petronia Carillo, Veronica De Micco, Michele Ciriello, Luigi Formisano, Christophe El-Nakhel, Maria Giordano, Giuseppe Colla and Youssef Rouphael
Plants 2022, 11(15), 2030; https://doi.org/10.3390/plants11152030 - 4 Aug 2022
Cited by 13 | Viewed by 2016
Abstract
A promising strategy for sustainably increasing the quality and yield of horticultural products is the use of natural plant biostimulants. In this work, through a greenhouse experiment, we evaluated the effect of a legume-derived biostimulant at three dose treatments (0.0 control, 2.5 mL [...] Read more.
A promising strategy for sustainably increasing the quality and yield of horticultural products is the use of natural plant biostimulants. In this work, through a greenhouse experiment, we evaluated the effect of a legume-derived biostimulant at three dose treatments (0.0 control, 2.5 mL L−1, and 5.0 mL L−1) on the yield performance, nutrients traits, leaf anatomical traits, gas exchanges, and carbon photosynthetic assimilation of greenhouse lettuce. The lettuce plants were foliar sprayed every 7 days for 5 weeks. The application of plant biostimulant, at both lower and higher dosages, increased the nutrient use efficiency, root dry weight, and leaf area. However, it is noteworthy that the 5.0 mL L−1 dose enhanced photosynthetic activity in the early phase of growth (15 DAT), thus supplying carbon skeletons useful for increasing the number of leaves and their efficiency (higher SPAD), and for boosting nutrient uptake (P, S, and K) and transport to leaves, while the 2.5 mL L−1 dose exerted specific effects on roots, increasing their dimension and enabling them to better use nitrate and Ca. A higher dose of biostimulant application might find its way in shorter growing cycle, thus presenting new horizons for new lines of research in baby leaves production. Full article
(This article belongs to the Special Issue Biostimulants as Regulators of Carbon and Nitrogen Metabolism in Plants)
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36 pages, 3316 KiB  
Review
Management and Utilization of Plant Genetic Resources for a Sustainable Agriculture
by Ranjith Pathirana and Francesco Carimi
Plants 2022, 11(15), 2038; https://doi.org/10.3390/plants11152038 - 4 Aug 2022
Cited by 33 | Viewed by 5448
Abstract
Despite the dramatic increase in food production thanks to the Green Revolution, hunger is increasing among human populations around the world, affecting one in nine people. The negative environmental and social consequences of industrial monocrop agriculture is becoming evident, particularly in the contexts [...] Read more.
Despite the dramatic increase in food production thanks to the Green Revolution, hunger is increasing among human populations around the world, affecting one in nine people. The negative environmental and social consequences of industrial monocrop agriculture is becoming evident, particularly in the contexts of greenhouse gas emissions and the increased frequency and impact of zoonotic disease emergence, including the ongoing COVID-19 pandemic. Human activity has altered 70–75% of the ice-free Earth’s surface, squeezing nature and wildlife into a corner. To prevent, halt, and reverse the degradation of ecosystems worldwide, the UN has launched a Decade of Ecosystem Restoration. In this context, this review describes the origin and diversity of cultivated species, the impact of modern agriculture and other human activities on plant genetic resources, and approaches to conserve and use them to increase food diversity and production with specific examples of the use of crop wild relatives for breeding climate-resilient cultivars that require less chemical and mechanical input. The need to better coordinate in situ conservation efforts with increased funding has been highlighted. We emphasise the need to strengthen the genebank infrastructure, enabling the use of modern biotechnological tools to help in genotyping and characterising accessions plus advanced ex situ conservation methods, identifying gaps in collections, developing core collections, and linking data with international databases. Crop and variety diversification and minimising tillage and other field practices through the development and introduction of herbaceous perennial crops is proposed as an alternative regenerative food system for higher carbon sequestration, sustaining economic benefits for growers, whilst also providing social and environmental benefits. Full article
(This article belongs to the Special Issue 10th Anniversary of Plants—Recent Advances and Perspectives)
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13 pages, 4317 KiB  
Article
Seed Priming with Chitosan Improves Germination Characteristics Associated with Alterations in Antioxidant Defense and Dehydration-Responsive Pathway in White Clover under Water Stress
by Yao Ling, Yue Zhao, Bizhen Cheng, Meng Tan, Yan Zhang and Zhou Li
Plants 2022, 11(15), 2015; https://doi.org/10.3390/plants11152015 - 2 Aug 2022
Cited by 9 | Viewed by 2256
Abstract
Water stress decreases seed-germination characteristics and also hinders subsequent seedling establishment. Seed priming with bioactive compounds has been proven as an effective way to improve seed germination under normal and stressful conditions. However, effect and mechanism of seed priming with chitosan (CTS) on [...] Read more.
Water stress decreases seed-germination characteristics and also hinders subsequent seedling establishment. Seed priming with bioactive compounds has been proven as an effective way to improve seed germination under normal and stressful conditions. However, effect and mechanism of seed priming with chitosan (CTS) on improving seed germination and seedling establishment were not well-understood under water-deficit conditions. White clover (Trifolium repens) seeds were pretreated with or without 5 mg/L CTS before being subjected to water stress induced by 18% (w/v) polyethylene glycol 6000 for 7 days of germination in a controlled growth chamber. Results showed that water stress significantly decreased germination percentage, germination vigor, germination index, seed vigor index, and seedling dry weight and also increased mean germination time and accumulation of reactive oxygen species, leading to membrane lipid peroxidation during seed germination. These symptoms could be significantly alleviated by the CTS priming through activating superoxide dismutase, catalase, and peroxidase activities. In addition, seeds pretreated with CTS exhibited significantly higher expression levels of genes encoding dehydration-responsive transcription factors (DREB2, DREB4, and DREB5) and dehydrins (Y2K, Y2SK, and SK2) than those seeds without the CTS priming. Current findings indicated that the CTS-induced tolerance to water stress could be associated with the enhancement in dehydration-responsive pathway during seed germination. Full article
(This article belongs to the Special Issue Stress Biology of Turfgrass)
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14 pages, 696 KiB  
Article
Insecticidal Activity of Four Essential Oils Extracted from Chilean Patagonian Plants as Potential Organic Pesticides
by Cristiano Giordani, Eleonora Spinozzi, Cecilia Baldassarri, Marta Ferrati, Loredana Cappellacci, Daniela Santibañez Nieto, Roman Pavela, Renato Ricciardi, Giovanni Benelli, Riccardo Petrelli and Filippo Maggi
Plants 2022, 11(15), 2012; https://doi.org/10.3390/plants11152012 - 2 Aug 2022
Cited by 7 | Viewed by 2297
Abstract
Patagonia is a geographical area characterized by a wide plant biodiversity. Several native plant species are traditionally used in medicine by the local population and demonstrated to be sources of biologically active compounds. Due to the massive need for green and sustainable pesticides, [...] Read more.
Patagonia is a geographical area characterized by a wide plant biodiversity. Several native plant species are traditionally used in medicine by the local population and demonstrated to be sources of biologically active compounds. Due to the massive need for green and sustainable pesticides, this study was conducted to evaluate the insecticidal activity of essential oils (EOs) from understudied plants growing in this propitious area. Ciprés (Pilgerodendron uviferum), tepa (Laureliopsis philippiana), canelo (Drimys winteri), and paramela (Adesmia boronioides) EOs were extracted through steam distillation, and their compositions were analyzed through GC–MS analysis. EO contact toxicity against Musca domestica L., Spodoptera littoralis (Boisd.), and Culex quinquefasciatus Say was then evaluated. As a general trend, EOs performed better on housefly males over females. Ciprés EO showed the highest insecticidal efficacy. The LD50(90) values were 68.6 (183.7) and 11.3 (75.1) µg adult−1 on housefly females and males, respectively. All EOs were effective against S. littoralis larvae; LD50 values were 33.2–66.7 µg larva−1, and tepa EO was the most effective in terms of LD90 (i.e., <100 µg larva−1). Canelo, tepa, and paramela EOs were highly effective on C. quinquefasciatus larvae, with LC50 values < 100 µL L−1. Again, tepa EO achieved LD90 < 100 µL L−1. This EO was characterized by safrole (43.1%), linalool (27.9%), and methyl eugenol (6.9%) as major constituents. Overall, Patagonian native plant EOs can represent a valid resource for local stakeholders, to develop effective insecticides for pest and vector management, pending a proper focus on their formulation and nontarget effects. Full article
(This article belongs to the Special Issue Insecticidal Activity of Plant Secondary Metabolites)
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17 pages, 315 KiB  
Review
Extraction Methods, Quantitative and Qualitative Phytochemical Screening of Medicinal Plants for Antimicrobial Textiles: A Review
by Elvino Nortjie, Moses Basitere, Doice Moyo and Pardon Nyamukamba
Plants 2022, 11(15), 2011; https://doi.org/10.3390/plants11152011 - 2 Aug 2022
Cited by 32 | Viewed by 13530
Abstract
Medicinal plants are the product of natural drug discoveries and have gained traction due to their pharmacological activities. Pathogens are everywhere, and they thrive in ideal conditions depending on the nutrients, moisture, temperature, and pH that increase the growth of harmful pathogens on [...] Read more.
Medicinal plants are the product of natural drug discoveries and have gained traction due to their pharmacological activities. Pathogens are everywhere, and they thrive in ideal conditions depending on the nutrients, moisture, temperature, and pH that increase the growth of harmful pathogens on surfaces and textiles. Thus, antimicrobial agents and finishes may be the solution to the destruction of pathogens. This review article presents an analysis of various aspects of producing antimicrobial finishings, the microorganisms, their mechanism of attachment to natural and synthetic fibre, the effect of microbial growth, and the principle and mechanism of the microbial activity of the medicinal plants. Furthermore, the extraction methods, qualitative and quantitative phytochemical evaluations of antimicrobial efficacy, and developments of antimicrobial treated textiles using various agents are covered in this review. Full article
(This article belongs to the Special Issue Integrated Metabolomics and Plant Chemical Diversity)
19 pages, 4991 KiB  
Article
Antimicrobial Efficiency of Some Essential Oils in Antibiotic-Resistant Pseudomonas aeruginosa Isolates
by Luc Tran Van, Ilinca Hagiu, Adelina Popovici, Florica Marinescu, Irina Gheorghe, Carmen Curutiu, Lia Mara Ditu, Alina-Maria Holban, Tatiana Eugenia Sesan and Veronica Lazar
Plants 2022, 11(15), 2003; https://doi.org/10.3390/plants11152003 - 31 Jul 2022
Cited by 10 | Viewed by 2559
Abstract
Pseudomonas aeruginosa is a non-fermentative Gram-negative opportunistic pathogen, frequently encountered in difficult-to-treat hospital-acquired infections and also wastewaters. The natural resistance of this pathogen, together with the frequent occurrence of multidrug-resistant strains, make current antibiotic therapy inefficient in treating P. aeruginosa infections. Antibiotic therapy [...] Read more.
Pseudomonas aeruginosa is a non-fermentative Gram-negative opportunistic pathogen, frequently encountered in difficult-to-treat hospital-acquired infections and also wastewaters. The natural resistance of this pathogen, together with the frequent occurrence of multidrug-resistant strains, make current antibiotic therapy inefficient in treating P. aeruginosa infections. Antibiotic therapy creates a huge pressure to select resistant strains in clinical settings but also in the environment, since high amounts of antibiotics are released in waters and soil. Essential oils (EOs) and plant-derived compounds are efficient, ecologic, and sustainable alternatives in the management of various diseases, including infections. In this study, we evaluated the antibacterial effects of four commercial essential oils, namely, tea tree, thyme, sage, and eucalyptus, on 36 P. aeruginosa strains isolated from hospital infections and wastewaters. Bacterial strains were characterized in terms of virulence and antimicrobial resistance. The results show that most strains expressed soluble pore toxin virulence factors such as lecithinase (89–100%) and lipase (72–86%). All P. aeruginosa strains were positive for alginate encoding gene and 94.44% for protease IV; most of the strains were exotoxin producers (i.e., 80.56% for the ExoS gene, 77.78% for the ExoT gene, while the ExoU gene was present in 38.98% of the strains). Phospholipase-encoding genes (plc) were identified in 91.67/86.11% of the cases (plcH/plcN genes). A high antibiotic resistance level was identified, most of the strains being resistant to cabapenems and cephalosporins. Cabapenem resistance was higher in hospital and hospital wastewater strains (55.56–100%) as compared to those in urban wastewater. The most frequently encountered encoding genes were for extended spectrum β-lactamases (ESBLs), namely, blaCTX-M (83.33% of the strains), blaSHV (80.56%), blaGES (52.78%), and blaVEB (13.89%), followed by carbapenemase-encoding genes (blaVIM, 8.33%). Statistical comparison of the EOs’ antimicrobial results showed that thyme gave the lowest minimum inhibitory concentrations (MIC) and minimum biofilm eradication concentrations (MBEC) in P. aeruginosa-resistant isolates, making this EO a competitive candidate for the development of efficient and ecologic antimicrobial alternatives. Full article
(This article belongs to the Section Phytochemistry)
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14 pages, 1313 KiB  
Review
The Role of Transcription Factors in the Regulation of Plant Shoot Branching
by Lingling Zhang, Weimin Fang, Fadi Chen and Aiping Song
Plants 2022, 11(15), 1997; https://doi.org/10.3390/plants11151997 - 31 Jul 2022
Cited by 11 | Viewed by 4276
Abstract
Transcription factors, also known as trans-acting factors, balance development and stress responses in plants. Branching plays an important role in plant morphogenesis and is closely related to plant biomass and crop yield. The apical meristem produced during plant embryonic development repeatedly produces the [...] Read more.
Transcription factors, also known as trans-acting factors, balance development and stress responses in plants. Branching plays an important role in plant morphogenesis and is closely related to plant biomass and crop yield. The apical meristem produced during plant embryonic development repeatedly produces the body of the plant, and the final aerial structure is regulated by the branching mode generated by axillary meristem (AM) activities. These branching patterns are regulated by two processes: AM formation and axillary bud growth. In recent years, transcription factors involved in regulating these processes have been identified. In addition, these transcription factors play an important role in various plant hormone pathways and photoresponses regulating plant branching. In this review, we start from the formation and growth of axillary meristems, including the regulation of hormones, light and other internal and external factors, and focus on the transcription factors involved in regulating plant branching and development to provide candidate genes for improving crop architecture through gene editing or directed breeding. Full article
(This article belongs to the Special Issue Molecular Biology of Ornamental Plants)
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15 pages, 3172 KiB  
Article
Effect of Melatonin in Broccoli Postharvest and Possible Melatonin Ingestion Level
by Antonio Cano, Manuela Giraldo-Acosta, Sara García-Sánchez, Josefa Hernández-Ruiz and Marino B. Arnao
Plants 2022, 11(15), 2000; https://doi.org/10.3390/plants11152000 - 31 Jul 2022
Cited by 15 | Viewed by 2133
Abstract
The post-harvest stage of broccoli production requires cold storage to obtain enough days of shelf life. It has been proved that melatonin is useful as a post-harvest agent in fruits and vegetables, including broccoli. In this study, the broccoli heads treated with melatonin [...] Read more.
The post-harvest stage of broccoli production requires cold storage to obtain enough days of shelf life. It has been proved that melatonin is useful as a post-harvest agent in fruits and vegetables, including broccoli. In this study, the broccoli heads treated with melatonin have a longer shelf life than the control samples, which was reflected in parameters such as fresh weight, hue angle (expresses color quality), and chlorophyll and carotenoid contents. Treatments with 100 μM melatonin for 15 or 30 min seem to be the most appropriate, extending the broccoli’s shelf life to almost 42 days, when it is normally around 4 weeks. In addition, a study on the possible impact that melatonin treatments in broccoli could have on melatonin intake in humans is presented. The levels of superficial melatonin, called washing or residual melatonin, are measured, showing the possible incidence in estimated blood melatonin levels. Our results suggest that post-harvest treatments with melatonin do not have to be a handicap from a nutritional point of view, but more research is needed. Full article
(This article belongs to the Special Issue 10th Anniversary of Plants—Recent Advances and Perspectives)
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31 pages, 2318 KiB  
Review
Calluna vulgaris as a Valuable Source of Bioactive Compounds: Exploring Its Phytochemical Profile, Biological Activities and Apitherapeutic Potential
by Alexandra-Antonia Cucu, Gabriela-Maria Baci, Alexandru-Bogdan Cucu, Ştefan Dezsi, Cristian Lujerdean, Iuliana Cristina Hegeduş, Otilia Bobiş, Adela Ramona Moise and Daniel Severus Dezmirean
Plants 2022, 11(15), 1993; https://doi.org/10.3390/plants11151993 - 30 Jul 2022
Cited by 9 | Viewed by 3447
Abstract
Calluna vulgaris, belonging to the Ericaceae family, is an invasive plant that has widely spread from Europe all across Asia, North America, Australia and New Zealand. Being able to survive in rigid soil and environmental conditions, it is nowadays considered to be [...] Read more.
Calluna vulgaris, belonging to the Ericaceae family, is an invasive plant that has widely spread from Europe all across Asia, North America, Australia and New Zealand. Being able to survive in rigid soil and environmental conditions, it is nowadays considered to be of high nature-conservation value. Known for its nutritional and medicinal properties, C. vulgaris stands out for its varied physiochemical composition, spotlighting a wide range of biological activity. Among the most important bioactive compounds identified in C. vulgaris, the phenolic components found in different parts of this herbaceous plant are the main source of its diverse pro-health properties (antioxidant, anti-inflammatory, antimicrobial, chemoprotective, etc.). Nonetheless, this plant exhibits an excellent nectariferous potential for social insects such as honeybees; therefore, comparing the bioactive compounds observed in the plant and in the final product of the beehive, namely honey, will help us understand and find new insights into the health benefits provided by the consumption of C. vulgaris-related products. Thus, the main interest of this work is to review the nutritional profile, chemical composition and biological activities of the C. vulgaris plant and its related honey in order to encourage the future exploration and use of this health-promoting plant in novel foods, pharmacological products and apitherapy. Full article
(This article belongs to the Special Issue Identification and Analysis of Bioactive Components from Plants)
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24 pages, 6579 KiB  
Article
Seed Priming with Carbon Nanomaterials Improves the Bioactive Compounds of Tomato Plants under Saline Stress
by Yolanda González-García, Elsy Rubisela López-Vargas, Marissa Pérez-Álvarez, Gregorio Cadenas-Pliego, Adalberto Benavides-Mendoza, Jesús Valdés-Reyna, Fabián Pérez-Labrada and Antonio Juárez-Maldonado
Plants 2022, 11(15), 1984; https://doi.org/10.3390/plants11151984 - 30 Jul 2022
Cited by 13 | Viewed by 2970
Abstract
The consumption of food with a high content of bioactive compounds is correlated with the prevention of chronic degenerative diseases. Tomato is a food with exceptional nutraceutical value; however, saline stress severely affects the yield, the quality of fruits, and the agricultural productivity [...] Read more.
The consumption of food with a high content of bioactive compounds is correlated with the prevention of chronic degenerative diseases. Tomato is a food with exceptional nutraceutical value; however, saline stress severely affects the yield, the quality of fruits, and the agricultural productivity of this crop. Recent studies have shown that seed priming can mitigate or alleviate the negative effects caused by this type of stress. However, the use of carbon nanomaterials (CNMs) in this technique has not been tested for this purpose. In the present study, the effects of tomato seed priming with carbon nanotubes (CNTs) and graphene (GP) (50, 250, and 500 mg L−1) and two controls (not sonicated and sonicated) were evaluated based on the content of photosynthetic pigments in the leaves; the physicochemical parameters of the fruits; and the presence of enzymatic and non-enzymatic antioxidant compounds, carotenoids, and stress biomarkers such as hydrogen peroxide (H2O2) and malondialdehyde (MDA) in the leaves and fruits of tomato plants without saline stress and with saline stress (50 mM NaCl). The results show that saline stress in combination with CNTs and GP increased the content of chlorophylls (9.1–21.7%), ascorbic acid (19.5%), glutathione (≈13%), proteins (9.9–11.9%), and phenols (14.2%) on the leaves. The addition of CNTs and GP increased the activity of enzymes (CAT, APX, GPX, and PAL). Likewise, there was also a slight increase in the content of H2O2 (by 20.5%) and MDA (3.7%) in the leaves. Salinity affected the quality of tomato fruits. The physico-chemical parameters and bioactive compounds in both the stressed and non-stressed tomato plants were modified with the addition of CNTs and GP. Higher contents of total soluble solids (25.9%), phenols (up to 144.85%), flavonoids (up to 37.63%), ascorbic acid (≈28%), and lycopene (12.4–36.2%) were observed. The addition of carbon nanomaterials by seed priming in tomato plants subjected to saline stress modifies the content of bioactive compounds in tomato fruits and improves the antioxidant defense system, suggesting possible protection of the plant from the negative impacts of stress by salinity. However, analysis of the mechanism of action of CNMs through seed priming, in greater depth is suggested, perhaps with the use of omics sciences. Full article
(This article belongs to the Special Issue Effects of Nanoparticles on Plant Growth and Development under Biotic and Abiotic Stress)
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22 pages, 3336 KiB  
Article
Valorization of Traditional Italian Walnut (Juglans regia L.) Production: Genetic, Nutritional and Sensory Characterization of Locally Grown Varieties in the Trentino Region
by Erica A. Di Pierro, Pietro Franceschi, Isabella Endrizzi, Brian Farneti, Lara Poles, Domenico Masuero, Iuliia Khomenko, Francesco Trenti, Annarita Marrano, Urska Vrhovsek, Flavia Gasperi, Franco Biasioli, Graziano Guella, Luca Bianco and Michela Troggio
Plants 2022, 11(15), 1986; https://doi.org/10.3390/plants11151986 - 30 Jul 2022
Cited by 11 | Viewed by 2982
Abstract
Juglans regia (L.) is cultivated worldwide for its nutrient-rich nuts. In Italy, despite the growing demand, walnut cultivation has gone through a strong decline in recent decades, which led to Italy being among the top five net importing countries. To promote the development [...] Read more.
Juglans regia (L.) is cultivated worldwide for its nutrient-rich nuts. In Italy, despite the growing demand, walnut cultivation has gone through a strong decline in recent decades, which led to Italy being among the top five net importing countries. To promote the development of local high-quality Italian walnut production, we devised a multidisciplinary project to highlight the distinctive traits of three varieties grown in the mountainous region Trentino (northeast of Italy): the heirloom ‘Bleggiana’, a second local accession called local Franquette and the French cultivar ‘Lara’, recently introduced in the local production to increase yield. The genetic characterization confirmed the uniqueness of ‘Bleggiana’ and revealed local Franquette as a newly described autochthonous variety, thus named ‘Blegette’. The metabolic profiles highlighted a valuable nutritional composition of the local varieties, richer in polyphenols and with a lower ω-6/ω-3 ratio than the commercial ‘Lara’. ‘Blegette’ obtained the highest preference scores from consumers for both the visual aspect and tasting; however, the volatile organic compound profiles did not discriminate among the characterized cultivars. The described local varieties represent an interesting reservoir of walnut genetic diversity and quality properties, which deserve future investigation on agronomically useful traits (e.g., local adaptation and water usage) for a high-quality and sustainable production. Full article
(This article belongs to the Collection New Trends in Plant Science in Italy)
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14 pages, 1323 KiB  
Article
Genetic Diversity and Population Structure of Jubaea chilensis, an Endemic and Monotype Gender from Chile, Based on SNP Markers
by Paola Jara-Arancio, Carolina da Silva Carvalho, Martín R. Carmona-Ortiz, Ramiro O. Bustamante, Priscilla M. Schmidt Villela, Sónia C. da Silva Andrade, Francisco T. Peña-Gómez, Luís A. González and Marina Fleury
Plants 2022, 11(15), 1959; https://doi.org/10.3390/plants11151959 - 28 Jul 2022
Cited by 5 | Viewed by 2261
Abstract
Jubaea chilensis (Molina) Baill., also named Chilean palm, is an endemic species found in the coastal area of Mediterranean sclerophyllous forest in Chile. It has a highly restricted and fragmented distribution along the coast, being under intense exploitation and anthropogenic impact. Based on [...] Read more.
Jubaea chilensis (Molina) Baill., also named Chilean palm, is an endemic species found in the coastal area of Mediterranean sclerophyllous forest in Chile. It has a highly restricted and fragmented distribution along the coast, being under intense exploitation and anthropogenic impact. Based on 1038 SNP markers, we evaluated the genetic diversity and population structure among six J. chilensis natural groups encompassing 96% of the species distribution. We observed low levels of genetic diversity, a deficit of heterozygotes (mean HE = 0.024; HO = 0.014), and high levels of inbreeding (mean FIS = 0.424). The fixation index (FST) and Nei’s genetic distance pairwise comparisons indicated low to moderate structuring among populations. There was no evidence of isolation by distance (r = −0.214, p = 0.799). In the cluster analysis, we observed a closer relationship among Culimo, Cocalán, and Candelaria populations. Migration rates among populations were low, except for some populations with moderate values. The K value that best represented the spatial distribution of genetic diversity was ∆K = 3. Habitat fragmentation, deterioration of the sclerophyllous forest, lack of long-distance dispersers, and a natural regeneration deficit may have driven inbreeding and low levels of genetic diversity in the palm groves of J. chilensis. Although extant populations are not at imminent risk of extinction, the rate of inbreeding could increase and migration could decrease if the effects of climate change and human impact become more acute. Full article
(This article belongs to the Special Issue Plant Evolutionary Ecology)
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17 pages, 2737 KiB  
Article
Comparative Transcriptome Analysis of Grafted Tomato with Drought Tolerance
by Maria Isabel Fuentes-Merlos, Masaru Bamba, Shusei Sato and Atsushi Higashitani
Plants 2022, 11(15), 1947; https://doi.org/10.3390/plants11151947 - 27 Jul 2022
Cited by 7 | Viewed by 2310
Abstract
Grafting is a method used in agriculture to improve crop production and tolerance to biotic and abiotic stress. This technique is widely used in tomato, Solanum lycopersicum L.; however, the effects of grafting on changes in gene expression associated with stress tolerance in [...] Read more.
Grafting is a method used in agriculture to improve crop production and tolerance to biotic and abiotic stress. This technique is widely used in tomato, Solanum lycopersicum L.; however, the effects of grafting on changes in gene expression associated with stress tolerance in shoot apical meristem cells are still under-discovered. To clarify the effect of grafting, we performed a transcriptomic analysis between non-grafted and grafted tomatoes using the tomato variety Momotaro-scion and rootstock varieties, TD1, GS, and GF. Drought tolerance was significantly improved not only by a combination of compatible resistant rootstock TD1 but also by self-grafted compared to non-grafted lines. Next, we found the differences in gene expression between grafted and non-grafted plants before and during drought stress treatment. These altered genes are involved in the regulation of plant hormones, stress response, and cell proliferation. Furthermore, when comparing compatible (Momo/TD1 and Momo/Momo) and incompatible (Momo/GF) grafted lines, the incompatible line reduced gene expression associated with phytohormones but increased in wounding and starvation stress-response genes. These results conclude that grafting generates drought stress tolerance through several gene expression changes in the apical meristem. Full article
(This article belongs to the Special Issue Physiological and Molecular Mechanisms of Plant Grafting)
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11 pages, 2815 KiB  
Article
Chemical Constituents from the Aerial Parts of Artemisia iwayomogi and Their Anti-Neuroinflammatory Activities
by So-Ri Son, In Gyong Ju, Jinhee Kim, Keon-Tae Park, Myung Sook Oh and Dae Sik Jang
Plants 2022, 11(15), 1954; https://doi.org/10.3390/plants11151954 - 27 Jul 2022
Cited by 5 | Viewed by 1809
Abstract
Neuroinflammation, predominantly mediated by microglial activation, is a key immunological response in the pathogenesis of neurodegenerative disorders. In our preliminary study, the aerial part of Artemisia iwayomogi inhibits LPS-induced microglial activation. The present study aims to identify chemical constituents with anti-neuroinflammatory properties in [...] Read more.
Neuroinflammation, predominantly mediated by microglial activation, is a key immunological response in the pathogenesis of neurodegenerative disorders. In our preliminary study, the aerial part of Artemisia iwayomogi inhibits LPS-induced microglial activation. The present study aims to identify chemical constituents with anti-neuroinflammatory properties in the aerial parts of A. iwayomogi. Two new guaianolide sesquiterpenes, iwayomogins A and B (1 and 2), along with thirteen known sesquiterpene lactones (3–15), one diterpene glycoside (16), and nine phenolic compounds (17–25) were isolated from the aerial parts of A. iwayomogi by repeated chromatography. The structures of the isolates were elucidated by their spectroscopic data. All isolates were evaluated for their inhibitory activities on nitric oxide (NO) production in LPS-induced BV-2 microglial cells. 2,3-Dehydro-1-epi-asperilin (11) exhibited the strongest inhibitory effect on NO production (IC50 value of 1.78 μM). In the molecular docking study, three compounds (1, 2, and 11) showed good binding affinities with iNOS. Additionally, compounds 1, 2, and 11 inhibit pro-inflammatory cytokines (TNF-α and IL-6) in dose-dependent manners. The present study demonstrates that the chemical constituents from A. iwayomogi inhibit NO production and pro-inflammatory cytokine release in BV-2 cells. However, further evaluation with biological experiments utilizing in vivo models is necessary. Full article
(This article belongs to the Special Issue Biological Activities and Constituents of Plant-Derived Natural Products and Their Application)
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11 pages, 641 KiB  
Article
Chemical Composition and In Vitro Anti-Helicobacter pylori Activity of Campomanesia lineatifolia Ruiz & Pavón (Myrtaceae) Essential Oil
by Nívea Cristina Vieira Neves, Morgana Pinheiro de Mello, Sinéad Marian Smith, Fabio Boylan, Marcelo Vidigal Caliari and Rachel Oliveira Castilho
Plants 2022, 11(15), 1945; https://doi.org/10.3390/plants11151945 - 27 Jul 2022
Cited by 6 | Viewed by 2551
Abstract
Helicobacter pylori is the most common cause of gastritis and peptic ulcers, and the number of resistant strains to multiple conventional antimicrobial agents has been increasing in different parts of the world. Several studies have shown that some essential oils (EO) have bioactive [...] Read more.
Helicobacter pylori is the most common cause of gastritis and peptic ulcers, and the number of resistant strains to multiple conventional antimicrobial agents has been increasing in different parts of the world. Several studies have shown that some essential oils (EO) have bioactive compounds, which can be attributed to antimicrobial activity. Therefore, EOs have been proposed as a natural alternative to antibiotics, or for use in combination with conventional treatment for H. pylori infection. Campomanesia lineatifolia is an edible species found in the Brazilian forests, and their leaves are traditionally used for the treatment of gastrointestinal disorders. Anti-inflammatory, gastroprotective, and antioxidant properties are attributed to C. lineatifolia leaf extracts; however, studies related to the chemical constituents of the essential oil and anti-H. pylori activity is not described. This work aims to identify the chemical composition of the EO from C. lineatifolia leaves and evaluate the anti-H. pylori activity. The EO was obtained by hydrodistillation from C. lineatifolia leaves and characterized by gas chromatography–mass spectrometry analyses. To assess the in vitro anti-H. pylori activity of the C. lineatifolia leaf’s EO (6 μL/mL–25 μL/mL), we performed broth microdilution assays by using type cultures (ATCC 49503, NCTC 11638, both clarithromycin-sensitive) and clinical isolate strains (SSR359, clarithromycin-sensitive, and SSR366, clarithromycin-resistant). A total of eight new compounds were identified from the EO (3-hexen-1-ol (46.15%), α-cadinol (20.35%), 1,1-diethoxyethane (13.08%), 2,3-dicyano-7,7-dimethyl-5,6-benzonorbornadiene (10.78%), aromadendrene 2 (3.0%), [3-S-(3α, 3aα, 6α, 8aα)]-4,5,6,7,8,8a-hexahydro-3,7,7-trimethyl-8-methylene-3H-3a,6-methanoazulene (2.99%), α-bisabolol (0.94%), and β-curcumene (0.8%)), corresponding to 98.09% of the total oil composition. The EO inhibited the growth of all H. pylori strains tested (MIC 6 μL/mL). To our knowledge, the current study investigates the relation between the chemical composition and the anti-H. pylori activity of the C. lineatifolia EO for the first time. Our findings show the potential use of the C. lineatifolia leaf EO against sensitive and resistant clarithromycin H. pylori strains and suggest that this antimicrobial activity could be related to its ethnopharmacological use. Full article
(This article belongs to the Special Issue Medicinal Plants: Advances in Phytochemistry and Ethnobotany)
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25 pages, 753 KiB  
Review
Use of Biostimulants as a New Approach for the Improvement of Phytoremediation Performance—A Review
by Maria Luce Bartucca, Martina Cerri, Daniele Del Buono and Cinzia Forni
Plants 2022, 11(15), 1946; https://doi.org/10.3390/plants11151946 - 27 Jul 2022
Cited by 31 | Viewed by 4354
Abstract
Environmental pollution is one of the most pressing global issues, and it requires priority attention. Environmental remediation techniques have been developed over the years and can be applied to polluted sites, but they can have limited effectiveness and high energy consumption and costs. [...] Read more.
Environmental pollution is one of the most pressing global issues, and it requires priority attention. Environmental remediation techniques have been developed over the years and can be applied to polluted sites, but they can have limited effectiveness and high energy consumption and costs. Bioremediation techniques, on the other hand, represent a promising alternative. Among them, phytoremediation is attracting particular attention, a green methodology that relies on the use of plant species to remediate contaminated sites or prevent the dispersion of xenobiotics into the environment. In this review, after a brief introduction focused on pollution and phytoremediation, the use of plant biostimulants (PBs) in the improvement of the remediation effectiveness is proposed. PBs are substances widely used in agriculture to raise crop production and resistance to various types of stress. Recent studies have also documented their ability to counteract the deleterious effects of pollutants on plants, thus increasing the phytoremediation efficiency of some species. The works published to date, reviewed and discussed in the present work, reveal promising prospects in the remediation of polluted environments, especially for heavy metals, when PBs derived from humic substances, protein and amino acid hydrolysate, inorganic salts, microbes, seaweed, plant extracts, and fungi are employed. Full article
(This article belongs to the Special Issue Phytoremediation: New Approaches and Perspectives)
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17 pages, 3278 KiB  
Article
Deep Learning Diagnostics of Gray Leaf Spot in Maize under Mixed Disease Field Conditions
by Hamish A. Craze, Nelishia Pillay, Fourie Joubert and Dave K. Berger
Plants 2022, 11(15), 1942; https://doi.org/10.3390/plants11151942 - 26 Jul 2022
Cited by 8 | Viewed by 2599
Abstract
Maize yields worldwide are limited by foliar diseases that could be fungal, oomycete, bacterial, or viral in origin. Correct disease identification is critical for farmers to apply the correct control measures, such as fungicide sprays. Deep learning has the potential for automated disease [...] Read more.
Maize yields worldwide are limited by foliar diseases that could be fungal, oomycete, bacterial, or viral in origin. Correct disease identification is critical for farmers to apply the correct control measures, such as fungicide sprays. Deep learning has the potential for automated disease classification from images of leaf symptoms. We aimed to develop a classifier to identify gray leaf spot (GLS) disease of maize in field images where mixed diseases were present (18,656 images after augmentation). In this study, we compare deep learning models trained on mixed disease field images with and without background subtraction. Performance was compared with models trained on PlantVillage images with single diseases and uniform backgrounds. First, we developed a modified VGG16 network referred to as “GLS_net” to perform binary classification of GLS, which achieved a 73.4% accuracy. Second, we used MaskRCNN to dynamically segment leaves from backgrounds in combination with GLS_net to identify GLS, resulting in a 72.6% accuracy. Models trained on PlantVillage images were 94.1% accurate at GLS classification with the PlantVillage testing set but performed poorly with the field image dataset (55.1% accuracy). In contrast, the GLS_net model was 78% accurate on the PlantVillage testing set. We conclude that deep learning models trained with realistic mixed disease field data obtain superior degrees of generalizability and external validity when compared to models trained using idealized datasets. Full article
(This article belongs to the Special Issue Deep Learning in Plant Sciences)
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16 pages, 7696 KiB  
Article
Genome-Wide Identification of R2R3-MYB Transcription Factor and Expression Analysis under Abiotic Stress in Rice
by Lihua Kang, Yangyang Teng, Qiwen Cen, Yunxia Fang, Quanxiang Tian, Xiaoqin Zhang, Hua Wang, Xian Zhang and Dawei Xue
Plants 2022, 11(15), 1928; https://doi.org/10.3390/plants11151928 - 25 Jul 2022
Cited by 16 | Viewed by 2639
Abstract
The myeloblastosis (MYB) family comprises a large group of transcription factors (TFs) that has a variety of functions. Among them, the R2R3-MYB type of proteins are the largest group in plants, which are involved in controlling various biological processes such as plant growth [...] Read more.
The myeloblastosis (MYB) family comprises a large group of transcription factors (TFs) that has a variety of functions. Among them, the R2R3-MYB type of proteins are the largest group in plants, which are involved in controlling various biological processes such as plant growth and development, physiological metabolism, defense, and responses to abiotic and biotic stresses. In this study, bioinformatics was adopted to conduct genome-wide identification of the R2R3-MYB TFs in rice. We identified 190 MYB TFs (99 R2R3-MYBs), which are unevenly distributed on the 12 chromosomes of rice. Based on the phylogenetic clustering and protein sequence characteristics, OsMYBs were classified into five subgroups, and 59.6% of the Os2R_MYB genes contained two introns. Analysis of cis-acting elements in the 2000 bp upstream region of Os2R_MYB genes showed that all Os2R_MYB genes contained plant hormones-related or stress-responsive elements since 91.9%, 79.8%, 79.8%, and 58.6% of Os2R_MYB genes contain ABRE, TGACG, CGTCA, and MBS motifs, respectively. Protein–protein network analysis showed that the Os2R_MYBs were involved in metabolic process, biosynthetic process, and tissue development. In addition, some genes showed a tissue-specific or developmental-stage-specific expression pattern. Moreover, the transcription levels of 20 Os2R_MYB genes under polyethylene glycol (PEG) and cadmium chloride (CdCl2) stress inducers were dissected by qRT-PCR. The results indicated genes with an altered expression upon PEG or CdCl2 stress induction. These results potentially supply a basis for further research on the role that Os2R_MYB genes play in plant development and stress responses. Full article
(This article belongs to the Special Issue Transcriptome Analysis and Gene Regulation in Plant Growth Development)
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17 pages, 4373 KiB  
Article
Prediction of Greenhouse Tomato Crop Evapotranspiration Using XGBoost Machine Learning Model
by Jiankun Ge, Linfeng Zhao, Zihui Yu, Huanhuan Liu, Lei Zhang, Xuewen Gong and Huaiwei Sun
Plants 2022, 11(15), 1923; https://doi.org/10.3390/plants11151923 - 25 Jul 2022
Cited by 34 | Viewed by 2946
Abstract
Crop evapotranspiration estimation is a key parameter for achieving functional irrigation systems. However, ET is difficult to directly measure, so an ideal solution was to develop a simulation model to obtain ET. There are many ways to calculate ET, most of which use [...] Read more.
Crop evapotranspiration estimation is a key parameter for achieving functional irrigation systems. However, ET is difficult to directly measure, so an ideal solution was to develop a simulation model to obtain ET. There are many ways to calculate ET, most of which use models based on the Penman–Monteith equation, but they are often inaccurate when applied to greenhouse crop evapotranspiration. The use of machine learning models to predict ET has gradually increased, but research into their application for greenhouse crops is relatively rare. We used experimental data for three years (2019–2021) to model the effects on ET of eight meteorological factors (net solar radiation (Rn), mean temperature (Ta), minimum temperature (Tamin), maximum temperature (Tamax), relative humidity (RH), minimum relative humidity (RHmin), maximum relative humidity (RHmax), and wind speed (V)) using a greenhouse drip irrigated tomato crop ET prediction model (XGBR-ET) that was based on XGBoost regression (XGBR). The model was compared with seven other common regression models (linear regression (LR), support vector regression (SVR), K neighbors regression (KNR), random forest regression (RFR), AdaBoost regression (ABR), bagging regression (BR), and gradient boosting regression (GBR)). The results showed that Rn, Ta, and Tamax were positively correlated with ET, and that Tamin, RH, RHmin, RHmax, and V were negatively correlated with ET. Rn had the greatest correlation with ET (r = 0.89), and V had the least correlation with ET (r = 0.43). The eight models were ordered, in terms of prediction accuracy, XGBR-ET > GBR-ET > SVR-ET > ABR-ET > BR-ET > LR-ET > KNR-ET > RFR-ET. The statistical indicators mean square error (0.032), root mean square error (0.163), mean absolute error (0.132), mean absolute percentage error (4.47%), and coefficient of determination (0.981) of XGBR-ET showed that XGBR-ET modeled daily ET for greenhouse tomatoes well. The parameters of the XGBR-ET model were ablated to show that the order of importance of meteorological factors on XGBR-ET was Rn > RH > RHmin> Tamax> RHmax> Tamin> Ta> V. Selecting Rn, RH, RHmin, Tamax, and Tamin as model input variables using XGBR ensured the prediction accuracy of the model (mean square error 0.047). This study has value as a reference for the simplification of the calculation of evapotranspiration for drip irrigated greenhouse tomato crops using a novel application of machine learning as a basis for an effective irrigation program. Full article
(This article belongs to the Special Issue Crop-Water Relations: Improving Water Use Efficiency in a Changing Climate)
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15 pages, 948 KiB  
Article
Bio-Priming of Soybean with Bradyrhizobium japonicum and Bacillus megaterium: Strategy to Improve Seed Germination and the Initial Seedling Growth
by Dragana Miljaković, Jelena Marinković, Gordana Tamindžić, Vuk Đorđević, Branislava Tintor, Dragana Milošević, Maja Ignjatov and Zorica Nikolić
Plants 2022, 11(15), 1927; https://doi.org/10.3390/plants11151927 - 25 Jul 2022
Cited by 23 | Viewed by 3485
Abstract
Bio-priming is a new technique of seed treatment that improves seed germination, vigor, crop growth and yield. The objective of this study was to evaluate the effectiveness of Bradyrhizobium japonicum (commercial strains) and Bacillus megaterium (newly isolated strains) as a single inoculant and [...] Read more.
Bio-priming is a new technique of seed treatment that improves seed germination, vigor, crop growth and yield. The objective of this study was to evaluate the effectiveness of Bradyrhizobium japonicum (commercial strains) and Bacillus megaterium (newly isolated strains) as a single inoculant and co-inoculant during seed bio-priming to improve seed germination and initial seedling growth of two soybean cultivars. The treated seeds were subjected to germination test (GT), cold test (CT) and accelerated aging test (AAT). B. megaterium significantly improved all parameters in GT and CT; final germination, shoot length, root length, root dry weight, and seedling vigor index in AAT, as compared to control. In addition, co-inoculation significantly increased all parameters except shoot dry weight in GT; all parameters in CT; germination energy, shoot length, root length, and seedling vigor index in AAT, in comparison to the control. Moreover, Br. japonicum significantly improved the germination energy, shoot length, shoot dry weight, root dry weight, and seedling vigor index in GT; all parameters in CT; shoot length, root length, and seedling vigor index in AAT, compared with non-primed seeds. Thus, B. megaterium strains could be used in soybean bio-priming as a potential single inoculant and co-inoculant, following proper field evaluation. Full article
(This article belongs to the Section Plant Protection and Biotic Interactions)
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17 pages, 2298 KiB  
Article
Dermal Penetration Studies of Potential Phenolic Compounds Ex Vivo and Their Antioxidant Activity In Vitro
by Aurita Butkeviciute, Kristina Ramanauskiene, Vaida Kurapkiene and Valdimaras Janulis
Plants 2022, 11(15), 1901; https://doi.org/10.3390/plants11151901 - 22 Jul 2022
Cited by 7 | Viewed by 1558
Abstract
Phenolic compounds with miscellaneous biological activities are an interesting component in dermatology and cosmetology practices. The aim of our study was to determine the phenolic compounds released from emulsion, emulgel, gel, ointment, and oleogel formulations penetration into human skin layers, both the epidermis [...] Read more.
Phenolic compounds with miscellaneous biological activities are an interesting component in dermatology and cosmetology practices. The aim of our study was to determine the phenolic compounds released from emulsion, emulgel, gel, ointment, and oleogel formulations penetration into human skin layers, both the epidermis and dermis, and estimate their antioxidant activity. The ex vivo penetration study was performed using Bronaugh type flow-through diffusion cells. Penetration studies revealed that, within 24 h, the chlorogenic acid released from the oleogel penetrated into skin layers to a depth of 2.0 ± 0.1 µg/mL in the epidermis and 1.5 ± 0.07 µg/mL in the dermis. The oleogel-released complex of phenolic compounds penetrating into epidermis showed the strongest DPPH free radical scavenging activity (281.8 ± 14.1 µM TE/L). The study estimated a strong positive correlation (r = 0.729) between the amount of quercetin penetrated into epidermis and the antioxidant activity detected in the epidermis extract. Plant based phenolic compounds demonstrated antioxidant activity and showed great permeability properties through the skin. Full article
(This article belongs to the Special Issue Natural Resources of Medicinal and Cosmetic Plants Volume II)
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12 pages, 1538 KiB  
Article
Estimation of Morphological Features and Essential Oil Content of Basils (Ocimum basilicum L.) Grown under Different Conditions
by Danguolė Juškevičienė, Audrius Radzevičius, Pranas Viškelis, Nijolė Maročkienė and Rasa Karklelienė
Plants 2022, 11(14), 1896; https://doi.org/10.3390/plants11141896 - 21 Jul 2022
Cited by 5 | Viewed by 1942
Abstract
This study was carried out in the experimental field and in unheated greenhouses of the Lithuanian Research Centre for Agriculture and Forestry Institute of Horticulture. The investigation aimed to evaluate the morphological features, amount of essential oil, and productivity of 10 basil ( [...] Read more.
This study was carried out in the experimental field and in unheated greenhouses of the Lithuanian Research Centre for Agriculture and Forestry Institute of Horticulture. The investigation aimed to evaluate the morphological features, amount of essential oil, and productivity of 10 basil (Ocimum basilicum L.) cultivars grown under different growing conditions. Studied cultivars were different according to morphological parameters, productivity, and the accumulation of essential oil. Most of the investigated parameters were influenced by growing conditions. Basil plants of cultivars Sweet Genovese and Toscano were determined to be the highest, and their height reached up to 70.5 cm. Cultivar Sweet Genovese was the most productive; its fresh herb mass per plant reached up to 0.71 kg under growing in the open field and greenhouse. Higher air temperature and constant watering of the soil in the greenhouse increased the accumulation of essential oils of basil. The biochemical analyses showed that the essential oil amount of 31% was higher when basils were grown in a greenhouse compared to an open field. Full article
(This article belongs to the Special Issue Selected Papers from Conference of CYSENI 2022)
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18 pages, 992 KiB  
Review
Physiological and Molecular Responses of Woody Plants Exposed to Future Atmospheric CO2 Levels under Abiotic Stresses
by Ana Karla M. Lobo, Ingrid C. A. Catarino, Emerson A. Silva, Danilo C. Centeno and Douglas S. Domingues
Plants 2022, 11(14), 1880; https://doi.org/10.3390/plants11141880 - 20 Jul 2022
Cited by 11 | Viewed by 3073
Abstract
Climate change is mainly driven by the accumulation of carbon dioxide (CO2) in the atmosphere in the last century. Plant growth is constantly challenged by environmental fluctuations including heat waves, severe drought and salinity, along with ozone accumulation in the atmosphere. [...] Read more.
Climate change is mainly driven by the accumulation of carbon dioxide (CO2) in the atmosphere in the last century. Plant growth is constantly challenged by environmental fluctuations including heat waves, severe drought and salinity, along with ozone accumulation in the atmosphere. Food security is at risk in an increasing world population, and it is necessary to face the current and the expected effects of global warming. The effects of the predicted environment scenario of elevated CO2 concentration (e[CO2]) and more severe abiotic stresses have been scarcely investigated in woody plants, and an integrated view involving physiological, biochemical and molecular data is missing. This review highlights the effects of elevated CO2 in the metabolism of woody plants and the main findings of its interaction with abiotic stresses, including a molecular point of view, aiming to improve the understanding of how woody plants will face the predicted environmental conditions. Overall, e[CO2] stimulates photosynthesis and growth and attenuates mild to moderate abiotic stress in woody plants if root growth and nutrients are not limited. Moreover, e[CO2] does not induce acclimation in most tree species. Some high-throughput analyses involving omics techniques were conducted to better understand how these processes are regulated. Finally, knowledge gaps in the understanding of how the predicted climate condition will affect woody plant metabolism were identified, with the aim of improving the growth and production of this plant species. Full article
(This article belongs to the Special Issue The Effect of Carbon Dioxide Concentration on Plant Physiology)
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19 pages, 2423 KiB  
Article
The Warps and Wefts of a Polyploidy Complex: Integrative Species Delimitation of the Diploid Leucanthemum (Compositae, Anthemideae) Representatives
by Tankred Ott, Maximilian Schall, Robert Vogt and Christoph Oberprieler
Plants 2022, 11(14), 1878; https://doi.org/10.3390/plants11141878 - 19 Jul 2022
Cited by 8 | Viewed by 2172
Abstract
Species delimitation—owing to the paramount role of the species rank in evolutionary, ecological, and nature conservation studies—is an essential contribution of taxonomy to biodiversity research. In an ‘integrative taxonomy’ approach to species delimitation on the diploid level, we searched for evolutionary significant units [...] Read more.
Species delimitation—owing to the paramount role of the species rank in evolutionary, ecological, and nature conservation studies—is an essential contribution of taxonomy to biodiversity research. In an ‘integrative taxonomy’ approach to species delimitation on the diploid level, we searched for evolutionary significant units (the warps and wefts) that gave rise to the polyploid complex of European ox-eye daisies (Leucanthemum; Compositae-Anthemideae). Species discovery and validation methods based on genetic, ecological, geographical, and morphometric datasets were applied to test the currently accepted diploid morpho-species, i.e., morphologically delimited species, in Leucanthemum. Novel approaches were taken in the analyses of RADseq data (consensus clustering), morphometrics of reconstructed leaf silhouettes from digitized herbarium specimens, and quantification of species-distribution overlaps. We show that 17 of the 20 Leucanthemum morpho-species are supported by genetic evidence. The taxonomic rank of the remaining three morpho-species was resolved by combining genealogic, ecologic, geographic, and morphologic data in the framework of von Wettstein’s morpho-geographical species concept. We herewith provide a methodological pipeline for the species delimitation in an ‘integrative taxonomy’ fashion using sources of evidence from genealogical, morphological, ecological, and geographical data in the philosophy of De Queiroz’s “Unified Species Concept”. Full article
(This article belongs to the Special Issue Integrative Taxonomy of Plants)
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16 pages, 3100 KiB  
Article
The Imbibition of Pea (Pisum sativum L.) Seeds in Silver Nitrate Reduces Seed Germination, Seedlings Development and Their Metabolic Profile
by Joanna Szablińska-Piernik, Lesław Bernard Lahuta, Karolina Stałanowska and Marcin Horbowicz
Plants 2022, 11(14), 1877; https://doi.org/10.3390/plants11141877 - 19 Jul 2022
Cited by 9 | Viewed by 2691
Abstract
The use of silver nanoparticles (Ag NPs) on plants is accompanied by the occurrence of Ag+ ions, so the research of the effects of both on plants should be related. Therefore, in our study, the effects of Ag NPs suspension (containing Ag [...] Read more.
The use of silver nanoparticles (Ag NPs) on plants is accompanied by the occurrence of Ag+ ions, so the research of the effects of both on plants should be related. Therefore, in our study, the effects of Ag NPs suspension (containing Ag0 at 20 mg/L) and AgNO3 solutions (with the concentration of Ag+ ions at 20 and 50 mg/L) on the seed germination and early seedling growth (4 days) of pea (Pisum sativum L.) were compared. Both Ag NPs and AgNO3 did not decrease seed germination, and even stimulated seedling growth. In seedlings developing in the Ag NPs suspension, an increase in monosaccharides, homoserine and malate was noted. In the next experiment, the effect of short-term seed imbibition (8 h) in AgNO3 at elevated concentrations, ranging from 100 to 1000 mg/L, on the further seed germination, seedling growth (in absence of AgNO3) and their polar metabolic profiles were evaluated. The seed imbibition in AgNO3 solutions at 500 and 1000 mg/L reduced seed germination, inhibited seedlings’ growth and caused morphological deformations (twisting and folding of root). The above phytotoxic effects were accompanied by changes in amino acids and soluble carbohydrates profiles, in both sprouts and cotyledons. In deformed sprouts, the content of homoserine and asparagine (major amino acids) decreased, while alanine, glutamic acid, glutamine, proline, GABA (γ-aminobutyric acid) and sucrose increased. The increase in sucrose coincided with a decrease in glucose and fructose. Sprouts, but not cotyledons, also accumulated malic acid and phosphoric acid. Additionally, cotyledons developed from seeds imbibed with AgNO3 contained raffinose and stachyose, which were not detectable in sprouts and cotyledons of control seedlings. The obtained results suggest the possible disturbances in the mobilization of primary (oligosaccharides) and presumably major storage materials (starch, proteins) as well as in the primary metabolism of developing seedlings. Full article
(This article belongs to the Special Issue Physiological and Molecular Mechanisms of Plant Response to Metal Stress)
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11 pages, 835 KiB  
Article
Rhizospheric Actinomycetes Revealed Antifungal and Plant-Growth-Promoting Activities under Controlled Environment
by Hazem S. Elshafie and Ippolito Camele
Plants 2022, 11(14), 1872; https://doi.org/10.3390/plants11141872 - 18 Jul 2022
Cited by 16 | Viewed by 2640
Abstract
Actinomycetes has large habitats and can be isolated from terrestrial soil, rhizospheres of plant roots, and marine sediments. Actinomycetes produce several bioactive secondary metabolites with antibacterial, antifungal, and antiviral properties. In this study, some Actinomycetes strains were isolated from the rhizosphere zone of [...] Read more.
Actinomycetes has large habitats and can be isolated from terrestrial soil, rhizospheres of plant roots, and marine sediments. Actinomycetes produce several bioactive secondary metabolites with antibacterial, antifungal, and antiviral properties. In this study, some Actinomycetes strains were isolated from the rhizosphere zone of four different plant species: rosemary, acacia, strawberry, and olive. The antagonistic activity of all isolates was screened in vitro against Escherichia coli and Bacillus megaterium. Isolates with the strongest bioactivity potential were selected and molecularly identified as Streptomyces sp., Streptomyces atratus, and Arthrobacter humicola. The growth-promoting activity of the selected Actinomycetes isolates was in vivo evaluated on tomato plants and for disease control against Sclerotinia sclerotiorum. The results demonstrated that all bacterized plants with the studied Actinomycetes isolates were able to promote the tomato seedlings’ growth, showing high values of ecophysiological parameters. In particular, the bacterized seedlings with Streptomyces sp. and A. humicola showed low disease incidence of S. sclerotiorum infection (0.3% and 0.2%, respectively), whereas those bacterized with S. atratus showed a moderate disease incidence (7.6%) compared with the positive control (36.8%). In addition, the ability of the studied Actinomycetes to produce extracellular hydrolytic enzymes was verified. The results showed that A. humicola was able to produce chitinase, glucanase, and protease, whereas Streptomyces sp. and S. atratus produced amylase and pectinase at high and moderate levels, respectively. This study highlights the value of the studied isolates in providing bioactive metabolites and extracellular hydrolytic enzymes, indicating their potential application as fungal-biocontrol agents. Full article
(This article belongs to the Special Issue Biocontrol of Plant Diseases: Antagonist Microorganisms, Biostimulants, Induced Resistance (IR))
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35 pages, 6064 KiB  
Review
Fertilizers and Fertilization Strategies Mitigating Soil Factors Constraining Efficiency of Nitrogen in Plant Production
by Przemysław Barłóg, Witold Grzebisz and Remigiusz Łukowiak
Plants 2022, 11(14), 1855; https://doi.org/10.3390/plants11141855 - 15 Jul 2022
Cited by 31 | Viewed by 5219
Abstract
Fertilizer Use Efficiency (FUE) is a measure of the potential of an applied fertilizer to increase its impact on the uptake and utilization of nitrogen (N) present in the soil/plant system. The productivity of N depends on the supply of those nutrients in [...] Read more.
Fertilizer Use Efficiency (FUE) is a measure of the potential of an applied fertilizer to increase its impact on the uptake and utilization of nitrogen (N) present in the soil/plant system. The productivity of N depends on the supply of those nutrients in a well-defined stage of yield formation that are decisive for its uptake and utilization. Traditionally, plant nutritional status is evaluated by using chemical methods. However, nowadays, to correct fertilizer doses, the absorption and reflection of solar radiation is used. Fertilization efficiency can be increased not only by adjusting the fertilizer dose to the plant’s requirements, but also by removing all of the soil factors that constrain nutrient uptake and their transport from soil to root surface. Among them, soil compaction and pH are relatively easy to correct. The goal of new the formulas of N fertilizers is to increase the availability of N by synchronization of its release with the plant demand. The aim of non-nitrogenous fertilizers is to increase the availability of nutrients that control the effectiveness of N present in the soil/plant system. A wide range of actions is required to reduce the amount of N which can pollute ecosystems adjacent to fields. Full article
(This article belongs to the Special Issue Improving Fertilizer Use Efficiency–Methods and Strategies for the Future)
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20 pages, 1335 KiB  
Review
Management of Post-Harvest Anthracnose: Current Approaches and Future Perspectives
by Alice Ciofini, Francesca Negrini, Riccardo Baroncelli and Elena Baraldi
Plants 2022, 11(14), 1856; https://doi.org/10.3390/plants11141856 - 15 Jul 2022
Cited by 23 | Viewed by 4709
Abstract
Anthracnose is a severe disease caused by Colletotrichum spp. on several crop species. Fungal infections can occur both in the field and at the post-harvest stage causing severe lesions on fruits and economic losses. Physical treatments and synthetic fungicides have traditionally been the [...] Read more.
Anthracnose is a severe disease caused by Colletotrichum spp. on several crop species. Fungal infections can occur both in the field and at the post-harvest stage causing severe lesions on fruits and economic losses. Physical treatments and synthetic fungicides have traditionally been the preferred means to control anthracnose adverse effects; however, the urgent need to decrease the use of toxic chemicals led to the investigation of innovative and sustainable protection techniques. Evidence for the efficacy of biological agents and vegetal derivates has been reported; however, their introduction into actual crop protection strategies requires the solutions of several critical issues. Biotechnology-based approaches have also been explored, revealing the opportunity to develop innovative and safe methods for anthracnose management through genome editing and RNA interference technologies. Nevertheless, besides the number of advantages related to their use, e.g., the putative absence of adverse effects due to their high specificity, a number of aspects remain to be clarified to enable their introduction into Integrated Pest Management (IPM) protocols against Colletotrichum spp. disease. Full article
(This article belongs to the Special Issue Interactions between Colletotrichum Species and Plants Ⅱ)
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11 pages, 289 KiB  
Article
Salicylic Acid Improves Growth and Physiological Attributes and Salt Tolerance Differentially in Two Bread Wheat Cultivars
by Neila Abdi, Angeline Van Biljon, Chrisna Steyn and Maryke Tine Labuschagne
Plants 2022, 11(14), 1853; https://doi.org/10.3390/plants11141853 - 15 Jul 2022
Cited by 15 | Viewed by 1856
Abstract
Abiotic constraints such as salinity stress reduce cereal production. Salicylic acid is an elicitor of abiotic stress tolerance in plants. The aim of this study was to investigate the effects of salicylic acid on two bread wheat cultivars (SST806 and PAN3497) grown under [...] Read more.
Abiotic constraints such as salinity stress reduce cereal production. Salicylic acid is an elicitor of abiotic stress tolerance in plants. The aim of this study was to investigate the effects of salicylic acid on two bread wheat cultivars (SST806 and PAN3497) grown under salt stress (100 and 200 mM NaCl) in the presence and absence of 0.5 mM salicylic acid. The highest salt concentration (200 mM), in both PAN3497 and SST806, increased the days to germination and reduced the coleoptile and radicle dry weights. The shoot dry weight was reduced by 75 and 39%, root dry weight by 73 and 37%, spike number of both by 50%, spike weight by 73 and 54%, grain number by 62 and 15%, grain weight per spike by 80 and 45%, and 1000 grain weight by 9 and 29% for 200 and 100 mM NaCl, respectively. Salicylic acid in combination with 100 mM and 200 mM NaCl increased the shoot, root, and yield attributes. Salicylic acid increased the grain protein content, especially at 200 mM NaCl, and the increase was higher in SST806 than PAN3497. The macro-mineral concentration was markedly increased by an increase of NaCl. This was further increased by salicylic acid treatment for both SST806 and PAN3497. Regarding micro-minerals, Na was increased more than the other minerals in both cultivars. Mn, Zn, Fe, and Cu were increased under 100 mM and 200 Mm of salt, and salicylic acid application increased these elements further in both cultivars. These results suggested that salicylic acid application improved the salt tolerance of these two bread wheat cultivars. Full article
(This article belongs to the Topic Plant Responses and Tolerance to Salinity Stress)
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