Ginkgo biloba L. leaf extracts and herbal infusions are used worldwide due to the health benefits that are attributed to its use, including anti-neoplastic, anti-aging, neuro-protection, antioxidant and others. The aim of this study was to evaluate the effect of an aqueous Ginkgo biloba extract on HepG2 cell viability, genotoxicity and DNA protection against paraquat-induced oxidative damage. Exposure to paraquat (PQ), over 24 h incubation at 1.0 and 1.5 µM, did not significantly reduce cell viability but induced concentration and time-dependent oxidative DNA damage. Ginkgo biloba leaf extract produced dose-dependent cytotoxicity (IC₅₀ = 540.8 ± 40.5 µg/mL at 24 h exposure), and short incubations (1 h) produced basal and oxidative DNA damage (>750 and 1500 µg/mL, respectively). However, lower concentrations (e.g., 75 µg/mL) of Ginkgo biloba leaf extract were not cytotoxic and reduced basal DNA damage, indicating a protective effect at incubations up to 4 h. On the other hand, longer incubations (24 h) induced oxidative DNA damage. Co-incubation of HepG2 cells for 4 h, with G. biloba leaf extract (75 µg/mL) and PQ (1.0 or 1.5 µM) significantly reduced PQ-induced oxidative DNA damage. In conclusion, the consumption of Ginkgo biloba leaf extract for long periods at high doses/concentrations is potentially toxic; however, low doses protect the cells against basal oxidative damage and against environmentally derived toxicants that induce oxidative DNA damage. Full article

Plant materials (i.e., leaves, fruits, and seeds) from 40 trees of Azadirachta indica A. Juss. were collected from six different locations across the Colombian Caribbean coast. Eighty-four ethanolic extracts were prepared and the total limonoid contents (TLiC) and the antifungal activity against Fusarium oxysporum conidia were measured. Their chemical profiles were also recorded via liquid chromatography-electrospray ionization interface-mass spectrometry (LC-ESI-MS) analysis and the top-ranked features were then annotated after supervised multivariate statistics. Inter-location chemical variability within sample set was assessed by sparse partial least squares discriminant analysis (sPLS-DA) and the chemical profiles and biological activity datasets were integrated through single-Y orthogonal partial least squares (OPLS) to identify antifungal bioactives in test extracts. The TLiC and antifungal activity (IC₅₀ values) of the A. indica-derived extracts were found to be ranging from 4.5 to 48.5 mg limonin equivalent per g dry extract and 0.08–44.8 μg/mL, respectively. The presence/abundance of particular limonoids between collected samples influenced the variability among locations. In addition, the integration of chemical and antifungal activity datasets showed five features as markers probably contributing to the bioactivity, annotated as compounds with an azadirone-like moiety. To validate the information provided by the single-Y OPLS model, a high performance liquid chromatography (HPLC)-based microfractionation was then carried out on an active extract. The combined plot of chromatographic profile and microfraction bioactivity also evidenced five signals possessing the highest antifungal activity. The most active limonoid was identified as nimonol 1. Hence, this untargeted metabolite profiling was considered as a convenient tool for identifying metabolites as inter-location markers as well as antifungals against Fusarium oxysporum. Full article

Copper (Cu) toxicity in plants may lead to iron (Fe), zinc (Zn) and manganese (Mn) deficiencies. Here, we investigated the effect of Si and Fe supply on the concentrations of micronutrients and metal-chelating amino acids nicotianamine (NA) and histidine (His) in leaves of cucumber plants exposed to Cu in excess. Cucumber (Cucumis sativus L.) was treated with 10 µM Cu, and additional 100 µM Fe or/and 1.5 mM Si for five days. High Cu and decreased Zn, Fe and Mn concentrations were found in Cu treatment. Additional Fe supply had a more pronounced effect in decreasing Cu accumulation and improving the molar ratio between micronutrients as compared to the Si supply. However, the simultaneous supply of Fe and Si was the most effective treatment in alleviation of Cu-induced deficiency of Fe, Zn and Mn. Additional Fe supply increased the His but not NA concentration, while Si supply significantly increased both NA and His whereby the NA:Cu and His:Cu molar ratios exceeded the control values indicating that Si recruits Cu-chelation to achieve Cu tolerance. In conclusion, Si-mediated alleviation of Cu toxicity was directed toward Cu tolerance while Fe-alleviative effect was due to a dramatic decrease in Cu accumulation. Full article

Extreme weather events are one of the biggest dangers posed by climate breakdown. As the temperatures increase, droughts and desertification will render whole regions inhospitable to agriculture. At the same time, other regions might suffer significant crop losses due to floods. Usually, regional food shortages can be covered by surpluses from elsewhere on the planet. However, the climate breakdown could trigger sustained food supply disruptions globally. Therefore, it is necessary to develop more stress-resilient crop alternatives by both breeding new varieties and promoting underutilized crop species (orphan crops). The articles in this special issue cover responses of staple crops and orphan crops to abiotic stresses relevant under the climate breakdown, such as heat, water, high salinity, nitrogen, and heavy metal stresses. This information will certainly complement a toolkit that can help inform, support, and influence the design of measures to deal with the climate crisis. Full article

Artemisia absinthium and Psidium guajava are powerful sources of secondary metabolites, some of them with potential allelopathic activity. Both the species grow together in India with a weed (Parthenium hysterophorus) that is becoming extremely invasive. The aim of the present research was to test the allelopathic effect of A. absinthium and P. guajava aqueous leaf extracts on seed germination, seedling growth (shoot and root length), as well as some biochemical parameters (enzymatic and non-enzymatic antioxidants, photosynthetic pigments, osmolytes, and malondialdehyde by-products) of P. hysterophorus plants. Leaf extracts of both A. absinthium and P. guajava constrained the germination and seedling development (root and shoot length), affected pigment content (chlorophylls, carotenoids), stimulated the activity of antioxidant enzymes, and increased the level of malondialdehyde by-products of P. hysterophorus plants. Non-enzymatic antioxidants (glutathione and ascorbic acid) in P. hysterophorus leaves were, conversely, negatively affected by both leaf extracts tested in the present experiment. Although A. absinthium was more effective than P. guajava in impacting some biochemical parameters of P. hysterophorus leaves (including a higher EC50 for seed germination), P. guajava extract showed a higher EC50 in terms of root inhibition of P. hysterophorus seedlings. The present study provides the evidence that A. absinthium and P. guajava extract could be proficiently exploited as a botanical herbicide against P. hysterophorus. Full article

Carotenoids are C40 isoprenoids synthesized by plants, as well as some bacteria, fungi and algae, that have been reported to be responsible for a number of benefits conferred on human health. The inability of animals and humans to synthesize de novo these compounds is the reason why they must be introduced from dietary sources. In cereal grains, carotenoids are important phytochemicals responsible for the characteristic yellow colour of the endosperm, which confers nutritional and aesthetic quality to cereal-based products. Cereals are staple foods for a large portion of the world population, and the biofortification of cereal grains with carotenoids may represent a simple way to prevent many human diseases and disorders. Unfortunately, evidence exists that the storage and processing of cereal grains into food products may negatively impact their carotenoid content; so, this loss should be taken into consideration when analysing the potential health benefits of the cereal-based products. Focusing on the recent updates, this review summarizes the chemical composition of the carotenoids in the grains of staple cereals, including wheat, maize, rice and sorghum, the main factors that affect their carotenoid content during storage and processing and the most fruitful strategies used improve the grain carotenoid content and limit the carotenoid post-harvest losses. Full article

The photoperiod-insensitivity allele e1 is known to be essential for the extremely low photoperiod sensitivity of rice, and thereby enabled rice cultivation in high latitudes (42–53° north (N)). The E1 locus regulating photoperiod-sensitivity was identified on chromosome 7 using a cross between T65 and its near-isogenic line T65w. Sequence analyses confirmed that the E1 and the Ghd7 are the same locus, and haplotype analysis showed that the e1/ghd7-0a is a pioneer allele that enabled rice production in Hokkaido (42–45° N). Further, we detected two novel alleles, e1-ret/ghd7-0ret and E1-r/Ghd7-r, each harboring mutations in the promoter region. These mutant alleles alter the respective expression profiles, leading to marked alteration of flowering time. Moreover, e1-ret/ghd7-0ret, as well as e1/ghd7-0a, was found to have contributed to the establishment of Hokkaido varieties through the marked reduction effect on photoperiod sensitivity, whereas E1-r/Ghd7-r showed a higher expression than the E1/Ghd7 due to the nucleotide substitutions in the cis elements. The haplotype analysis showed that two photoperiod-insensitivity alleles e1/ghd7-0a and e1-ret/ghd7-0ret, originated independently from two sources. These results indicate that naturally occurring allelic variation at the E1/Ghd7 locus allowed expansion of the rice cultivation area through diversification and fine-tuning of flowering time. Full article

High temperatures and drought are common stresses limiting crop growth and productivity in subtropical regions where citrus are produced. In addition to impacts on physiological processes such as transpiration, photosynthesis, and respiration, excessive solar radiation can also reduce fruit productivity by inducing physiological disorders such as sunburn. This study evaluated the effects of radiation reflectants and anti-transpirants on leaf physiology, and fruit sunburn in grapefruit trees (Citrus x paradisi Macfs. cv. Rio Red) in south Texas during the 2016 and 2017 growing seasons. Two calcium-based reflectants, and a methene/pinolene-based anti-transpirant were foliar applied to fruit-bearing trees. Reflectants reduced fruit and leaf temperatures by 0.2°C and 0.21°C, respectively, while the anti-transpirant treatments increased fruit and leaf temperature by approximately 0.83°C and 0.2°C relative to the controls. Stomatal conductance decreased by 1.3% and 3.3%, respectively, in response to the reflectant treatments, while anti-transpirant treatments resulted in decreased stomatal conductance (8.3%) relative to the controls. More sunburned fruit were found in anti-transpirant treated trees in both years (6% and 8.2% for 2016 and 2017) and the reflectant treatments reduced sunburn incidence by 4.9% and 1.8% in those years. These observations indicate that reflectant applications could be a viable strategy to mitigate heat/radiation stress and sunburn in grapefruit. Full article

The total contents and qualitative compositions of alkaloids in seeds of 10 Old World lupin species (73 accessions) were surveyed using gas chromatography. The obtained results, combined with those for three lupin crops, Lupinus angustifolius, Lupinus albus, and Lupinus luteus, provide the most complete and up-to-date overview of alkaloid profiles of 13 lupin species originating from the Mediterranean Basin. The qualitative alkaloid compositions served as useful supplementary tools of species discrimination. On the basis of the most abundant major alkaloids, lupanine, lupinine, and multiflorine, the Old World lupin species were divided into four groups. Those containing lupanine (L. angustifolius, L. albus, and Lupinus mariae-josephi), containing lupinine (Lupinus luteus, Lupinus hispanicus, and Lupinus × hispanicoluteus), containing lupinine and multiflorine (Lupinus atlanticus, Lupinus palaestinus, Lupinus anatolicus, Lupinus digitatus, Lupinus pilosus, and Lupinus cosentinii), and containing multiflorine (Lupinus micranthus). Within a given group, certain species can be, in most cases, further distinguished by the presence of other major alkaloids. The discrimination of species based on the total alkaloid content was found to be less reliable because of the significant intra-species variations, as well as the influences of environmental factors on the seed alkaloid content. Full article

The genus Lilium L. is widely distributed in the cold and temperate regions of the Northern Hemisphere and is one of the most valuable plant groups in the world. Regarding the classification of the genus Lilium, Comber’s sectional classification, based on the natural characteristics, has been primarily used to recognize species and circumscribe the sections within the genus. Although molecular phylogenetic approaches have been attempted using different markers to elucidate their phylogenetic relationships, there still are unresolved clades within the genus. In this study, we constructed the species tree for the genus using 28 Lilium species plastomes, including three currently determined species (L. candidum, L. formosanum, and L. leichtlinii var. maximowiczii). We also sought to verify Comber’s classification and to evaluate all loci for phylogenetic molecular markers. Based on the results, the genus was divided into two major lineages, group A and B, consisting of eastern Asia + Europe species and Hengduan Mountains + North America species, respectively. Sectional relationships revealed that the ancestor Martagon diverged from Sinomartagon species and that Pseudolirium and Leucolirion are polyphyletic. Out of all loci in that Lilium plastome, ycf1, trnF-ndhJ, and trnT-psbD regions are suggested as evaluated markers with high coincidence with the species tree. We also discussed the biogeographical diversification and long-distance dispersal event of the genus. Full article

p-Coumaric acid (p-CA) belongs to a family of natural esters of hydroxycinnamic acid compounds that have been shown to modulate plant growth and metabolism. In this study, we investigated the effect of exogenous p-CA on plant growth, reactive oxygen species (ROS)-induced oxidative damage, photosynthetic metabolism, osmolyte content and changes in superoxide dismutase (SOD) enzymatic activity. Exogenous p-CA improved Salvia hispanica (chia) growth by significantly enhancing shoot length, fresh and dry weights coupled with augmented levels of total chlorophyll and carotenoid contents. Furthermore, p-CA also triggered an induction in proline, glycine betaine (GB) and superoxide (O₂^∙−) levels while no changes were observed for hydrogen peroxide (H₂O₂) and downstream malondialdehyde (MDA) content. Also, no change in SOD activity was observed in the p-CA treatment relative to the control. Therefore, the results suggest that exogenous p-CA improves chia seedling growth possibly via activation of a ROS-signalling pathway involving O₂^∙− under the control of proline accumulation. Full article

The current study was conducted to explore the potential for phytoremediation in different varieties of jute grown under toxic concentrations of copper (Cu). For this purpose, a Petri dish experiment was conducted under controlled conditions using four varieties of jute, i.e., HongTieGuXuan, C-3, GuBaChangaJia, and ShangHuoMa, grown in double filter paper under 50 µmol L⁻¹ of artificially spiked copper (Cu) using CuSO₄.H₂O. The results of the present study revealed that jute varieties C-3 and HongTieGuXuan were able to survive under high concentrations of Cu without a significant decrease in plant height, plant fresh and dry weights, total chlorophyll content, or seed germination, while varieties GuBaChangaJia and ShangHuoMa exhibited a significant reduction in their growth and biomass. Furthermore, high concentrations of Cu in the medium resulted in lipid peroxidation. This could be due to the oxidative damage induced in the roots and leaves of the jute varieties, which might be a result of by hydrogen peroxide (H₂O₂) and electrolyte leakage. Reactive oxygen species (ROS) generated due to Cu toxicity can be overcome by the increasing activity of antioxidants, and it was also noted that GuBaChangaJia and ShangHuoMa exhibited high Cu stress, while C-3 and HongTieGuXuan showed some resistance to Cu toxicity. Contrastingly, Cu accumulation and uptake was higher in C-3 and HongTieGuXuan, while a little Cu was accumulated in the roots and leaves of GuBaChangaJia and ShangHuoMa. On the basis of these findings, it can be suggested that C-3 and HongTieGuXuan have the potential to cope with Cu stress and can be considered Cu-resistant varieties, while GuBaChangaJia and ShangHuoMa are considered Cu-sensitive varieties. Moreover, C-3 and HongTieGuXuan have the potential to revoke large amounts of Cu, and can be cultivated as phytoremediation tools in Cu-contaminated soil. Full article

The enemy-release hypothesis is one of the most popular but also most discussed hypotheses to explain invasion success. However, there is a lack of explicit, experimental tests of predictions of the enemy-release hypothesis (ERH), particularly regarding the effects of above- and belowground herbivory. Long-term studies investigating the relative effect of herbivores on invasive vs. native plant species within a community are still lacking. Here, we report on a long-term field experiment in an old-field community, invaded by Solidago canadensis s. l., with exclusion of above- and belowground insect herbivores. We monitored population dynamics of the invader and changes in the diversity and functioning of the plant community across eight years. Above- and belowground insects favoured the establishment of the invasive plant species and thereby increased biomass and decreased diversity of the plant community. Effects of invertebrate herbivores on population dynamics of S. canadensis appeared after six years and increased over time, suggesting that long-term studies are needed to understand invasion dynamics and consequences for plant community structure. We suggest that the release from co-evolved trophic linkages is of importance not only for the effect of invasive species on ecosystems, but also for the functioning of novel species assemblages arising from climate change. Full article

Thioredoxin (Trx) f and NADPH-dependent Trx reductase C (NTRC) have both been proposed as major redox regulators of starch metabolism in chloroplasts. However, little is known regarding the specific role of each protein in this complex mechanism. To shed light on this point, tobacco plants that were genetically engineered to overexpress the NTRC protein from the chloroplast genome were obtained and compared to previously generated Trx f-overexpressing transplastomic plants. Likewise, we investigated the impact of NTRC and Trx f deficiency on starch metabolism by generating Nicotiana benthamiana plants that were silenced for each gene. Our results demonstrated that NTRC overexpression induced enhanced starch accumulation in tobacco leaves, as occurred with Trx f. However, only Trx f silencing leads to a significant decrease in the leaf starch content. Quantitative analysis of enzyme activities related to starch synthesis and degradation were determined in all of the genotypes. Zymographic analyses were additionally performed to compare the amylolytic enzyme profiles of both transplastomic tobacco plants. Our findings indicated that NTRC overexpression promotes the accumulation of transitory leaf starch as a consequence of a diminished starch turnover during the dark period, which seems to be related to a significant reductive activation of ADP-glucose pyrophosphorylase and/or a deactivation of a putative debranching enzyme. On the other hand, increased starch content in Trx f-overexpressing plants was connected to an increase in the capacity of soluble starch synthases during the light period. Taken together, these results suggest that NTRC and the ferredoxin/Trx system play distinct roles in starch turnover. Full article

Plants respond to abiotic stresses by activating a specific genetic program that supports survival by developing robust adaptive mechanisms. This leads to accelerated senescence and reduced growth, resulting in negative agro-economic impacts on crop productivity. Cytokinins (CKs) customarily regulate various biological processes in plants, including growth and development. In recent years, cytokinins have been implicated in adaptations to osmotic stresses with improved plant growth and yield. Endogenous CK content under osmotic stresses can be enhanced either by transforming plants with a bacterial isopentenyl transferase (IPT) gene under the control of a stress inducible promoter or by exogenous application of synthetic CKs. CKs counteract osmotic stress-induced premature senescence by redistributing soluble sugars and inhibiting the expression of senescence-associated genes. Elevated CK contents under osmotic stress antagonize abscisic acid (ABA) signaling and ABA mediated responses, delay leaf senescence, reduce reactive oxygen species (ROS) damage and lipid peroxidation, improve plant growth, and ameliorate osmotic stress adaptability in plants. Full article