Plants — Open Access Journal

For centuries, humans have grown and used structures based on vascular tissues in plants. One could imagine that life would have developed differently without wood as a resource for building material, paper, heating energy, or fuel and without edible tubers as a food source. In this review, we will summarise the status of research on Arabidopsis thaliana vascular development and subsequently focus on how this knowledge has been applied and expanded in research on the wood of trees and storage organs of crop plants. We will conclude with an outlook on interesting open questions and exciting new research opportunities in this growing and important field. Full article

The capability of the soil bacterium Agrobacterium rhizogenes to reprogram plant development and induce adventitious hairy roots relies on the expression of a few root-inducing genes (rol A, B, C and D), which can be transferred from large virulence plasmids into the genome of susceptible plant cells. Contrary to rolA, B and C, which are present in all the virulent strains of A. rhizogenes and control hairy root formation by affecting auxin and cytokinin signalling, rolD appeared non-essential and not associated with plant hormones. Its role remained elusive until it was discovered that it codes for a proline synthesis enzyme. The finding that, in addition to its role in protein synthesis and stress adaptation, proline is also involved in hairy roots induction, disclosed a novel role for this amino acid in plant development. Indeed, from this initial finding, proline was shown to be critically involved in a number of developmental processes, such as floral transition, embryo development, pollen fertility and root elongation. In this review, we present a historical survey on the rol genes focusing on the role of rolD and proline in plant development. Full article

Root architecture and xylem phenotypic plasticity influence crop productivity by affecting water and nutrient uptake, especially under those environmental stress, which limit water supply or imply excessive water losses. Xylem maturation depends on coordinated events of cell wall lignification and developmental programmed cell death (PCD), which could both be triggered by developmental- and/or stress-driven hydrogen peroxide (H₂O₂) production. Here, the effect of wounding of the cotyledonary leaf on root protoxylem maturation was explored in Arabidopsis thaliana by analysis under Laser Scanning Confocal Microscope (LSCM). Leaf wounding induced early root protoxylem maturation within 3 days from the injury, as after this time protoxylem position was found closer to the tip. The effect of leaf wounding on protoxylem maturation was independent from root growth or meristem size, that did not change after wounding. A strong H₂O₂ accumulation was detected in root protoxylem 6 h after leaf wounding. Furthermore, the H₂O₂ trap N,N¹-dimethylthiourea (DMTU) reversed wound-induced early protoxylem maturation, confirming the need for H₂O₂ production in this signaling pathway. Full article

Quinoa (Chenopodium quinoa Willd.) is a genetically diverse Andean crop that has earned special attention worldwide due to its nutritional and health benefits and its ability to adapt to contrasting environments, including nutrient-poor and saline soils and drought stressed marginal agroecosystems. Drought and salinity are the abiotic stresses most studied in quinoa; however, studies of other important stress factors, such as heat, cold, heavy metals, and UV-B light irradiance, are severely limited. In the last few decades, the incidence of abiotic stress has been accentuated by the increase in unpredictable weather patterns. Furthermore, stresses habitually occur as combinations of two or more. The goals of this review are to: (1) provide an in-depth description of the existing knowledge of quinoa’s tolerance to different abiotic stressors; (2) summarize quinoa’s physiological responses to these stressors; and (3) describe novel advances in molecular tools that can aid our understanding of the mechanisms underlying quinoa’s abiotic stress tolerance. Full article

The antioxidant, antimicrobial, antiproliferative, and enzyme inhibitory properties of five extracts from aerial parts of Salvia pachyphylla Epling ex Munz were examined to assess the prospective of this plant as a source of natural products with therapeutic potential. These properties were analyzed by performing a set of standard assays. The extract obtained with dichloromethane showed the most variety of components, as they yielded promising results in all completed assays. Furthermore, the extract obtained with ethyl acetate exhibited the greatest antioxidant activity, as well as the best xanthine oxidase inhibitory activity. Remarkably, both extracts obtained with n-hexane or dichloromethane revealed significant antimicrobial activity against the Gram-positive bacteria; additionally, they showed greater antiproliferative activity against three representative cell lines of the most common types of cancers in women worldwide, and against a cell line that exemplifies cancers that typically develop drug resistance. Despite that, other extracts were less active, such as the methanolic or aqueous; their results are promising for the isolation and identification of novel bioactive molecules. Full article

In rural areas of Latin America, Hyptis infusions are very popular. Hyptis obtusiflora extends from Mexico throughout Central America to Bolivia and Peru. It has added value in Ecuador where it has been used by different ethnic groups. We aimed to learn about the traditional knowledge of ancient Kichwa cultures about this plant, and to contrast this knowledge with the published information organized in occidental databases. We proposed to use traditional knowledge as a source of innovation for social development. Our specific objectives were to catalogue the uses of H. obtusiflora in the community, to prospect on the bibliography on a possible chemical justification for its medicinal use, to propose new products for development, and to give arguments for biodiversity conservation. An ethnobotanical survey was made and a Prisma 2009 Flow Diagram was then followed for scientific validation. We rescued data that are novel contributions for the ethnobotany at the national level. The catalogued main activity of anti-inflammation can be related to the terpene composition and the inhibition of xanthine oxidase. This opens the possibility of researching the extract of this plant as an alternative to allopurinol or uricosuric drugs. This is a concrete example of an argument for biodiversity conservation. Full article

In the past years, the diversity of Capsicum has been mainly investigated through genetics and genomics approaches, fewer efforts have been made in the field of plant phenomics. Assessment of crop traits with high-throughput methodologies could enhance the knowledge of the plant phenome, giving at the same time a key contribution to the understanding of the function of many genes. In this study, a wide germplasm collection of 307 accessions retrieved from 48 world regions, and belonging to nine Capsicum species was characterized for 54 plant, leaf, flower and fruit traits. Conventional descriptors and semi-automated tools based on image analysis and colour coordinate detection were used. Significant differences were found among accessions, between species and between sweet and spicy cultivated types, revealing a large diversity. The results highlighted how the domestication process and the continued selection have increased the variability of fruit shape and colour. Hierarchical clustering based on conventional and fruit morphological descriptors reflected the separation of species on the basis of their phylogenetic relationships. These observations suggested that the flow between distinct gene pools could have contributed to determine the similarity of the species on the basis of morphological plant and fruit parameters. The approach used represents the first high-throughput phenotyping effort in Capsicum spp. aimed at broadening the knowledge of the diversity of domesticated and wild peppers. The data could help to select best the candidates for breeding and provide new insight into the understanding of the genetic base of the fruit shape of pepper. Full article

To detect the presence of neighboring vegetation, shade-avoiding plants have evolved the ability to perceive and integrate multiple signals. Among them, changes in light quality and quantity are central to elicit and regulate the shade avoidance response. Here, we describe recent progresses in the comprehension of the signaling mechanisms underlying the shade avoidance response, focusing on Arabidopsis, because most of our knowledge derives from studies conducted on this model plant. Shade avoidance is an adaptive response that results in phenotypes with a high relative fitness in individual plants growing within dense vegetation. However, it affects the growth, development, and yield of crops, and the design of new strategies aimed at attenuating shade avoidance at defined developmental stages and/or in specific organs in high-density crop plantings is a major challenge for the future. For this reason, in this review, we also report on recent advances in the molecular description of the shade avoidance response in crops, such as maize and tomato, and discuss their similarities and differences with Arabidopsis. Full article

Although wheat is a staple food for most of the human population, some of its components trigger adverse reactions. Among wheat components, the alpha-amylase/trypsin inhibitors (ATI) are important triggers of several allergies and activators of innate immunity. ATI are a group of exogenous protease inhibitors and include several polypeptides. The three ATI polypeptides named CM3, CM16 and 0.28 are considered major allergens, and might also play a role in other common wheat-related pathologies, such as Non Celiac Wheat Sensitivity and even Celiac Disease. On this basis, we pointed to obtain high amounts of them in purity and to evaluate their allergenicity potential. We thus isolated the mRNA corresponding to the three ATI genes CM3, CM16 and 0.28 from 28 days post-anthesis wheat kernels and the corresponding cDNAs were used for heterologous expression in Pichia pastoris. The three purified proteins were tested in degranulation assay against human sera of patients with food allergy to wheat. A large range of degranulation values was observed for each protein according to the sera tested. All of the three purified proteins CM3, CM16 and 0.28 were active as allergens because they were able to induce basophils degranulation on wheat allergic patients’ sera, with the highest values of β-hexosaminidase release observed for CM3 protein. Full article

Abiotic stress remains one of the major challenges in managing and preventing crop loss. Photosystem II (PSII), being the most susceptible component of the photosynthetic machinery, has been studied in great detail over many years. However, much of the emphasis has been placed on intrinsic proteins, particularly with respect to their involvement in the repair of PSII-associated damage. PSII extrinsic proteins include PsbO, PsbP, PsbQ, and PsbR in higher plants, and these are required for oxygen evolution under physiological conditions. Changes in extrinsic protein expression have been reported to either drastically change PSII efficiency or change the PSII repair system. This review discusses the functional role of these proteins in plants and indicates potential areas of further study concerning these proteins. Full article

Vegetables in Brassica are some of the world’s most commonly cultivated plants and have a wide range of consumable plant organs. Improvement of this group of vegetables is limited at the species level due to limited genetic variability. Interspecies hybridization could be a powerful alternate tool for broadening the genetic variability of target traits. Embryo rescue technique is necessarily practiced in interspecies hybridization for protecting embryos from premature abortion. However, its success depends on the age of ovaries, shape of embryos, and the effect of female genotype. In this study, we carried out a wide range of interspecies crossing for introgressing target traits (orange/yellow color in cabbage and anthocyanin in Chinese cabbage) and optimizing the appropriate age of ovaries, the shape of embryo, and the suitable genotypes of such crosses. We observed that 15 DAP (days after pollination) was the best for embryo rescue in the diploid-diploid (Brassica rapa × B. oleracea) crosses, while 20 DAP was optimum for amphidiploid-diploid (B. napus/B. juncea × B. rapa) crosses. Cotyledonary shape of embryos and genotypes of amphidiploid species were the best for successful plant regeneration in interspecies crosses. We successfully selected plants with desired orange/yellow inner leaves for cabbage and higher anthocyanin in Chinese cabbage. The results of this study have the potential to be applied for the efficient production of interspecific hybrids and to develop Brassica vegetables with new traits, which could have potential for the enrichment of the human diet. Full article

Flavonoids represent a wide group of plant secondary metabolites implicated in many physiological roles, from the attraction of pollinators to the protection against biotic or abiotic stresses. Flavonoids are synthetized in a number of horticultural crops that are important components of our daily diet. In the last decades, the consumption of vegetables rich in antioxidants has been strongly promoted from the perspective of prevention/protection against chronic diseases. Therefore, due to their nutritional importance, several attempts have been made to enhance flavonoid levels in species of agronomic interest. In this review, we focus on the flavonoid biodiversity among the major horticultural species, which is responsible of differences among closely related species and influences the qualitative/quantitative composition. We also review the role of flavonoids in the nutritional quality of plant products, contributing to their organoleptic and nutritional properties, and the main strategies of biofortification to increase their content. Full article

Mango (Mangifera indica L.), the sixth most important fruit crop worldwide, is likely at risk under a climate change scenario of accelerated soil organic matter mineralization and constrained plant nutrient supplies such as zinc (Zn) and boron (B). We identified the optimum nutrient formulation and application method to possibly rectify nutrient deficits in mango plants grown in one of the warmest and driest regions—Multan, Pakistan. We evaluated the yield and physiological (quality) responses of 20-year-old mango trees to seven treatments of foliar and soil applications of Zn and B. Combined soil application of B and Zn resulted in optimum increases in leaf mineral B and Zn and fruit-set, retention, yield, pulp recovery and total soluble solids at ripening (p = 0.021), while reducing titratable acidity and early fruit shedding (p = 0.034). Additionally, this treatment improved fruit quality (taste, flavour, texture, aroma, acceptability; p ≤ 0.05). Yield was found to be correlated with retention percentage (P ≤ 0.001; R² = 0.91), which was in turn related to fruit-set number panicle⁻¹ (P = 0.039; R² = 0.61). Therefore, we suggest that combined soil application of B and Zn mitigates leaf mineral deficiencies and improves the yield and quality of mango more efficiently than other individual or combined foliar or soil treatments used in this study. Full article

In present research, differences in the number of seeds per berry (NSB), berry fresh weight (BW), days to ripening from flowering (DRF), and the duration of a slow growth phase (DS II) among pollen sources were investigated in highbush blueberry (Vaccinium corymbosum). NSB, as well as BW and DRF, were significantly different among the pollen sources. Analysis of covariance (ANCOVA) with NSB as the covariate showed significant interaction between the NSB and pollen sources on BW and DRF when self-pollination was included. However, ANCOVA without self-pollination showed no significant effect of the pollen source on BW and DRF. On the other hand, DS II was negatively correlated with NSB, and no significant interaction between NSB and pollen sources was found, even though self-pollination was included. Although the relationship between NSB and DS II appeared not to be statistically influenced by the different pollen sources, there seemed to be some difference between self- and cross-pollination. DS II shortened as the NSB increased, which may have led to a decrease in DRF. Full article

Two modern rose varieties, Floribunda and Hybrid Tea, were used to analyze and identify metabolic changes after foliar application with benzyladenine (BA). Volatile organic compounds (VOCs) as metabolites were detected. Two pairs of doses of BA, at 11.16 and 17.87 mg/cm², and 7.17 and 12.26 mg/cm² were applied to the foliage of Hybrid Tea and Floribunda, respectively. Sampling time was optimized and treatment duration was 4 weeks. After treatment, the volatiles from the treated and untreated control roses were extracted using headspace solid-phase microextraction (HS-SPME) technology by three-phase fiber 50/30 µm divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS) and analyzed by gas chromatography (GC) coupled with a flame ionization detector (FID), and with mass spectrometry (GC-MS).The results showed that BA and its dose rate led to metabolic changes of treated roses in comparison with untreated controls. The number of VOCs extracted and detected from leaves, stem, rhizosphere and whole plants from the two rose varieties at doses rate of 17.87 and 12.26 mg/cm² were 43, 65, 40 and 68 compounds for each plant material, respectively, for both rose varieties. Whilst the VOCs extracted and detected from both rose varieties for leaves, stem, rhizosphere and whole plants were 38, 61, 34 and 66 compounds for each plant material, respectively. The results demonstrate that some volatiles, such as 4-Heptyn-2-ol, Phenyl methyl ether and 3-Methyl-apopinene, increased with increasing doses of BA; these compounds are aroma chemicals with a very powerful smell. This study shows that BA treatments can have a significant effect on metabolite changes in different rose tissues. This method could be applied to other floriculture plants. Full article

Essential nutrients and metals have been quantified in stems of many tree species to understand the role of stems as storage and source organs. Little is known about stored stem resources of cycad tree species. Cycas micronesica tissue was collected from apical and basal axial regions of stems; and pith, vascular, and cortex tissues were separated into three radial regions. Leaves were also sampled to provide a comparison to stems. Minerals and metals were quantified in all tissues. Minerals and metals varied greatly among the six stem sections. Phosphorus varied more among the three radial sections than the other macronutrients, and zinc and nickel varied more than the other micronutrients. Stem carbon was less than and stem calcium was greater than expected, based on what is currently known tree stem concentrations in the literature. Elemental concentrations were generally greater than those previously reported for coniferous gymnosperm trees. Moreover, the stem concentrations were high in relation to leaf concentrations, when compared to published angiosperm and conifer data. The results indicated that the addition of more cycad species to the literature will improve our understanding of gymnosperm versus angiosperm stem nutrient relations, and that the non-woody cycad stem contains copious essential plant nutrients that can be mobilized and deployed to sinks when needed. Full article

Immunolocalization studies to visualize the distribution of proteins on meiotic chromosomes have become an integral part of studies on meiosis in the model organism Arabidopsis thaliana. These techniques have been used to visualize a wide range of meiotic proteins involved in different aspects of meiosis, including sister chromatid cohesion, recombination, synapsis, and chromosome segregation. However, the analysis of meiotic spindle structure by immunofluorescence is of outstanding importance in plant reproductive biology and is very challenging. In the following report, we describe the complete and easy protocol for the localization of proteins to the male meiotic spindle and male meiotic chromosomes. The protocol is fast, improved, and robust without the use of any harsh enzymes. Full article

Sea fennel (Crithmum maritimum L.), a perennial halophyte typical of coastal habits, is well known for several food and non-food uses. This review presents both the characteristics and ethnobotany as well as the findings, technical advances and potential of sea fennel research with the aim to improve and disseminate knowledge regarding the value and potentials of this halophyte. Current knowledge suggest that sea fennel shows good potential as an emerging crop, being a refined food and also an interesting source of human health compounds and crop protection products. Moreover, sea fennel may be proposed as an alternative and sustainable cash crop also in the context of a saline agriculture regime. On the other hand, some aspects of sea fennel require further understanding; therefore, new research and development activities should be carried out before full commercial exploitation. Full article

Dracaena cinnabari Balf. f. (Dracaenaceae) is an important plant endemic to Soqotra Island, Yemen. Dragon’s blood (Dam Alakhwin) is the resin that exudes from the plant stem. The ethnobotanical survey was carried out by semi-structured questionnaires and open interviews to document the ethnobotanical data of the plant. According to the collected ethnobotanical data, the resin of D. cinnabari is widely used in the traditional folk medicine in Soqotra for treatment of dermal, dental, eye and gastrointestinal diseases in humans. The resin samples found on the local Yemeni markets were partly or totally substituted by different adulterants. Organoleptic properties, solubility and extractive value were demonstrated as preliminary methods to identify the authentic pure Soqotri resin as well as the adulterants. In addition, the resin extracts and its solution in methanol were investigated for their in vitro antifungal activities against six human pathogenic fungal strains by the agar diffusion method, for antioxidant activities using the DPPH assay and for cytotoxic activity using the neutral red uptake assay. The crude authentic resin dissolves completely in methanol. In comparison with different resin extracts, the methanolic solution of the whole resin showed the strongest biological activities. It showed strong antifungal activity, especially against Microsporum gypseum and Trichophyton mentagrophytes besides antioxidant activities and toxicity against FL-cells. These findings confirm and explain the traditional uses of the resin for the treatment of skin diseases and mouth fungal infections. Full article