Search Results (3,256)

Salicylic acid (SA) is a key endogenous regulator involved in plant defense responses to biotic and abiotic stresses. The increasing resistance of pathogens to chemical plant protection products and growing environmental restrictions have intensified the search for alternative strategies to enhance plant health and stress tolerance. Among these strategies, the induction of natural defense mechanisms, in which SA plays a central signaling role, has gained particular attention. This review summarizes current knowledge on the role of SA in shaping plant resistance to environmental factors. The fundamental mechanisms of plant defense, including innate immunity, induced systemic resistance (ISR), and systemic acquired resistance (SAR), are discussed, with emphasis on the signaling function of SA and its interaction with other phytohormones, especially jasmonic acid and ethylene. The role of SA in regulating physiological processes associated with stress tolerance, such as antioxidant system activity, photosynthesis, plant growth, and senescence, is highlighted. The review of research results indicates that appropriately selected doses and timing of SA treatments can enhance resistance to selected pathogens and improve plant tolerance to adverse environmental conditions. However, treatment effectiveness depends on multiple factors, particularly SA concentration and plant–pathogen interactions. Salicylic acid is a promising component of integrated and sustainable plant protection strategies. Further research, especially under field conditions, is necessary to optimize its practical use and fully determine its potential in modern agriculture. Full article

Hydroxycinnamoyl-CoA shikimate/quinate hydroxycinnamoyl transferase, a key acyltransferase in the phenylpropanoid pathway and a canonical member of the BAHD acyltransferase family (BAHD), catalyzes the formation of pivotal intermediates in the biosynthesis of secondary metabolites such as lignin, chlorogenic acid, and flavonoids. These compounds serve indispensable protective functions in terrestrial plants, underpinning their adaptive responses to abiotic stresses such as drought, ultraviolet (UV) radiation, and oxidative damage. Although the role of HCT/HQT in the core phenylpropanoid pathway has been extensively characterized, its precise functional contributions to the flavonoid biosynthetic branch—particularly with respect to substrate selectivity, kinetic regulation, and metabolic channeling—remain incompletely understood. This review systematically analyzes the structural features, spatial conformation, catalytic mechanism, and substrate promiscuity of HCT/HQT to clarify its molecular determinants of activity and specificity. Furthermore, it highlights regulatory factors influencing HCT/HQT gene expression, such as transcription factors (MYB, bHLH, WRKY), phytohormones (GA₃, Eth, MeJA, 6-BA, MT), and abiotic/biotic stressors (temperature, blue light, nitric oxide, nano-selenium). Collectively, these insights illuminate how plants dynamically fine-tune phenylpropanoid metabolism in coordination with developmental programs and environmental challenges. This work provides a foundation for further research on HCT/HQT and supports efforts to develop improved crop varieties through targeted regulation of this central metabolic node. Full article

The damage caused by herbivores is generally measured as the amount of leaf tissue consumed, without accounting for the fate of the leftover tissue. As a result, the plant defense mechanisms that promote resistance to herbivore feeding by photosynthetically acclimating the rest of the plant to the feeding spot leaf area have not been well exploited. Plant-insect interactions are now becoming better defined with the development of visualization methods that permit spatial whole-leaf assessment of photosynthetic efficiency after herbivore attack. The purpose of our study was to evaluate the spatial heterogeneity of photosystem II (PSII) function at the whole-leaf level before and after herbivory by the Colorado potato beetles. Twenty minutes after Colorado potato beetle (Leptinotarsa decemlineata) feeding, the maximum efficiency of PSII photochemistry (Fv/Fm) decreased significantly, suggesting photoinhibition due to reduced efficiency of the oxygen-evolving complex (OEC). The decreased quantum yield of PSII photochemistry (Φ_PSII) after feeding, at the neighboring area of the feeding spot and at the rest of the leaf area, was attributed to the reduced efficiency of the open PSII reaction centers (Fv′/Fm′), since there was no change in the fraction of open PSII reaction centers (qp). Nevertheless, plant defense elicitation was activated by the photoprotective mechanism of non-photochemical quenching (NPQ) that reduced the singlet oxygen (¹O₂) formation in potato plants in the neighboring area of the feeding spot and at the rest of the leaf area. In addition, the increased production of hydrogen peroxide (H₂O₂) triggered by this increase suggests that it acted as a signaling molecule in the biotic stress defense response. Full article

Genetically modified (GM) plants have been commercially grown for 30 years, and their acceptance depends on a thorough risk assessment. Environmental Risk Assessment (ERA) evaluates potential impacts of releasing GM plants into the environment, whether through cultivation or import for food, feed, and processing. A key component is assessing potential gene flow to crop wild relatives or non-GM crops. For gene flow to significantly affect the environment, transferred genes must provide a selective advantage. Since most GM plants are engineered for herbicide tolerance, insect resistance, or stacked traits, evaluating such advantages is relatively straightforward. New genomic techniques (NGTs) can generate plants with a wider range of traits, including tolerance to biotic and abiotic stress. Although still considered GM in the EU, their genomic changes can complicate detection, identification, and ERA, especially when such traits may offer advantages under stress conditions. This scoping review focuses on gene flow in two crops: oilseed rape (canola) (Brassica napus L.) and potato (Solanum tuberosum L.). In canola, transgene movement can increase weediness, fitness, herbicide resistance, or genetic diversity in feral or related populations. Gene flow in potato is less studied, with concerns centered on contamination risks in the Andean diversity center. Limited data exist for NGT plants, though many are expected to resemble conventionally bred varieties, suggesting comparable environmental impacts. Full article

Apple (Malus domestica Borkh.) is the most widely cultivated deciduous fruit tree with the largest industrial scale and the highest economic value in China. Fruit surface glossiness and plant stress tolerance are two core traits that determine the economic benefits and sustainable development of the apple industry. The plant epidermal cuticle is not only the core material basis for determining fruit glossiness but also the first barrier for plants to resist abiotic and biotic stresses. Glycosylphosphatidylinositol-anchored lipid transfer proteins (LTPGs) are the core functional factors mediating trans-cell wall lipid transport in plants. At present, the functions and action mechanisms of LTPG family members that simultaneously regulate fruit appearance quality and stress tolerance in apple remain largely unclear. In this study, we took the MdLTPG17 gene as the research object, clarified its biological function of stress resistance under drought stress, and dissected the molecular mechanism by which it mediates fruit glossiness formation via regulating fruit cuticle thickening. The results of this study provide important genetic resources and a theoretical basis for molecular breeding of stress resistance and targeted improvement of fruit appearance quality in apple. Full article

Climate change has adversely affected grain production and quality of canola, the second-largest oilseed crop, which contributes 13–16% of total vegetable oil. Multiple biotic and abiotic stresses significantly limit canola production due to rapid climate change, and conventional breeding alone is insufficient to meet global demand. Therefore, several advanced biotechnologies have been developed to cope with this change. Among these, genetic modification, gene editing, and RNA interference are particularly significant for rapid cultivar development in a cost-effective, efficient, and convenient way. Recent findings in gene editing applications have revealed “prospective sites”, highlighting regions amenable to precise editing without compromising canola plant growth or development. Pan-genome analyses have further guided gene editing target selection, enabling the validation of key stress-resilience genes across diverse canola cultivars, while the CRISPR-epigenetic regulatory connection enables targeted control of gene expression and trait modulation. A hypothetical application of genomic selection is also suggested, which could complement gene editing to accelerate the development of superior cultivars. Accordingly, this review focuses on the latest studies of genetic modification, gene editing, and RNA interference to strengthen canola resilience under rapid climate change and discusses the major concerns. Taken together, these genome-editing strategies offer precise approaches for improving biotic and abiotic stress tolerance, although careful consideration of both off-target effects and regulatory compliance remains essential for their practical implementation in canola improvement. Full article

Global freshwater scarcity is a pressing environmental challenge, particularly in Egypt, which depends entirely on the Nile River and its tributaries. Rapid population growth, domestic wastes, agricultural runoff, and rapid industrial expansion exert highly anthropogenic stress on aquatic ecosystems, including Bahr Yusuf and Ibrahimia Canals in Upper Egypt. This study aimed to evaluate the ecological health and sustainability status of the two canals using an integrated multi-metric framework combining physicochemical variables, microbiological indicators, and community structures of zooplankton and benthic fauna. Multivariate statistical analyses (PCA, CCA), and ecological indices, including the water quality index (WQI), microbial assessment index (MAI), Rotifer-Based Index (TSI_Rot) and Hilsenhoff Biotic Index, were applied to determine pollution gradients. The results revealed that Bahr Yusuf suffers from higher pollution levels than the Ibrahimia Canal. Canonical correspondence analysis (CCA) showed that nutrient enrichment and elevated organic load are responsible for over 72% of the variance in zooplankton and benthic invertebrate assemblage in both water bodies. The dominance of pollution-tolerant species, Philodina roseola and B. calyciflorus of zooplankton and Limnodrilus udekemianus, Chironomidae larvae, Melanoides tuberculate and Cleopatra bulimoides of benthic taxa, further indicates a direct increase in organic loading and nutrient enrichment from agricultural and domestic sources. According to the Integrated Water Quality–Biotic Health Index (IWQ-BHI), the downstream stations of Bahr Yusuf are critical risk zones, with scores below 50.0, while the upstream stations of Ibrahimia Canal fell within the “good” category, with scores exceeding 70.0. Overall, both waterbodies are approaching a critical threshold of ecological instability and require urgent, integrated and sustainable management to restore and preserve these vital freshwater ecosystems. Full article

Grapevine growth and physiological performance are strongly influenced by biotic and abiotic stresses occurring during the growing season. Plant stimulants are increasingly applied in viticulture as management tools aimed at supporting plant physiological processes and improving plant performance under variable environmental conditions; however, cultivar-specific responses to different application strategies remain insufficiently characterized. The aim of this study was to evaluate the effects of foliar plant stimulant application strategies differing in application frequency and phenological timing on selected physiological and canopy-related indicators in Slovak grapevine cultivars (Vitis vinifera L.) under field conditions. The assessed parameters included leaf chlorophyll a and b contents, chlorophyll a/b ratio, leaf area index (LAI), vegetation indices (NDVI and PRI), cluster weight, and basic must composition. Grapevines were subjected to three treatment variants: a control without plant stimulant application, a variant with two foliar applications, and a variant with three foliar applications of commercial biostimulants (Tecamin Max, Tecamin Flower, and Tecamin Brix) performed at key phenological stages during the growing season. Plant stimulant applications were associated with variations in leaf chlorophyll content and LAI values, particularly under repeated application strategies. NDVI and PRI complemented leaf-level measurements by capturing cultivar-dependent differences in canopy condition and photosynthetic regulation throughout the season. Responses of cluster weight and must composition to plant stimulant application were moderate and varied among cultivars, indicating cultivar-specific responses. Although no consistent increase in cluster yield was observed, treated variants showed higher sugar content and lower titratable acidity in several cultivars, indicating differences in grape composition and ripening-related traits. Overall, the results indicate that foliar plant stimulant application strategies can influence physiological and canopy-level grapevine traits in a cultivar-dependent manner. The combined use of leaf-level, canopy-level, and spectral indicators provides a practical framework for evaluating plant stimulant strategies under field conditions and supports their application in sustainable viticulture. Full article

Spider mites (Oligonychus trichardti) are emerging as a major constraint to Urochloa forage productivity in East Africa; however, knowledge of genotypic variation and tolerance remains limited. Herein, 55 Urochloa genotypes were evaluated under field-infested and non-infested conditions across two seasons using an alpha-lattice design. Agronomic and physiological traits, including plant height (PH), tiller number (TN), the Normalized Difference Vegetation Index (NDVI), total dry weight (TDW), and mite damage indices (visual severity index (VSI) and stress tolerance index (STI)) were assessed. Infestation reduced biomass by 22.4% on average, with reductions of up to 45% in susceptible genotypes. Significant genotypic variation was detected for PH, TN, TDW, and VSI. Heritability estimates under mite infestation were moderate to high for all traits except TDW, suggesting that direct selection of these traits could be effective in breeding programs aimed at improving mite resistance. VSI showed a strong negative correlation with NDVI (r = −0.63), supporting its value as a phenotyping indicator of spider mite response. Additive main effects and multiplicative interaction (AMMI) analysis revealed significant genotype × environment interactions for TDW. The AMMI biplot identified Xaraes, ILRI_13369, and ILRI_14787 as high-yielding and stable genotypes, while the AMMI Stability Value (ASV) and the Weighted Average of Absolute Scores from the Best Linear Unbiased Prediction (WAASB) identified CIAT_16122, CIAT_664, ILRI_14801, ILRI_14787, and ILRI_13266 as the most stable and broadly adapted across environments. STI further highlighted ILRI_13751 (2.71) and ILRI_13531 (2.58) as highly tolerant under stress. Overall, the study reveals substantial exploitable genetic diversity and identifies stable, high-yielding, and mite-tolerant genotypes suitable for breeding to improve Urochloa productivity in East Africa. Full article

Eucalyptus spp. are the most important timber and pulpwood species in southern China. This tree species is frequently and severely damaged by the leaf-eating pest Buzura suppressaria, which significantly impairs photosynthesis and hinders the healthy and sustainable development of the Eucalyptus industry. To investigate the defensive responses of Eucalyptus urophylla × Eucalyptus grandis to pest (B. suppressaria)-feeding and leaf-clipping stress, this study measured the temporal changes in defense enzyme activities and defense compounds in Eucalyptus under conditions of pest-feeding and leaf-clipping stresses, aiming to provide a theoretical basis for resistance breeding in Eucalyptus. The results show that pest-feeding and leaf-clipping stress groups significantly affected the peroxidase (POD), polyphenol oxidase (PPO), and phenylalanine ammonia-lyase (PAL) activities in Eucalyptus leaves. Within a short period after stress (3 h), POD activity was significantly reached 444.83 U by leaf-clipping stress, whereas it was significantly inhibited (34.83 U) by pest-feeding stress. PPO activity was significantly enhanced to 95.25 U under pest-feeding stress within 3 h, while leaf clipping induced a lower level of PPO activity (58.75 U). PAL activity was significantly induced to 474.38 U by leaf-clipping stress at 3 h, whereas pest-feeding stress resulted in a moderate increase to 238.00 U. Both pest-feeding and leaf-clipping stresses had significant effects on the contents of defense compounds in Eucalyptus leaves. Within a short period (3 h), both leaf-clipping and pest-feeding stresses significantly induced the accumulation of salicylic acid (0.226 μg/g and 0.326 μg/g, respectively), jasmonic acid (0.239 μg/g and 0.278 μg/g, respectively), and tannin (0.581 μg/g and 0.657 μg/g, respectively). The POD activity and salicylic acid content were identified as the primary factors in Eucalyptus responses to pest-feeding and leaf-clipping stresses. In conclusion, biotic (pest-feeding) and abiotic (leaf-clipping) stresses can induce higher activities of related defense enzymes while also promoting the synthesis of greater quantities of defensive chemical compounds, thereby enhancing the resilience to biotic and abiotic stresses in Eucalyptus. This study provides important practical guidance for insect-resistant Eucalyptus breeding and implementing integrated pest management strategies. Full article

Puccinia graminis f. sp. tritici (Pgt) is responsible for stem rust in wheat, a disease with worldwide occurrence. Ethylene response factors (ERFs), a group of transcription factors (TFs) responsive to ethylene, are essential for managing stress signaling under biotic and abiotic challenges. However, our understanding of ERF TFs’ function in wheat (Triticum aestivum L.) resistance against the obligate biotrophic Puccinia graminis f. sp. tritici remains limited. In this work, we report our findings of the TaERF109 gene, which is transcriptionally up-regulated by ethylene or Pgt infection. TaERF109 is localized in the nucleus of rice protoplasts. Results obtained using the yeast one-hybrid (Y1H) assay support the conclusion that TaERF109 interacts with the AGCCGCC sequence (GCC-box). Transient knockdown of TaERF109 via virus-induced gene silencing (VIGS) increased wheat susceptibility to Pgt, accompanied by the down-regulation of three pathogenesis-related (PR) genes, TaPR1, TaPR2, and TaPR10, as confirmed via real-time quantitative PCR. In contrast, the Agrobacterium-mediated overexpression of TaERF109 potentiated resistance of transgenic wheat against Pgt. Overall, these results expand the current understanding of the TaERF109 gene’s function in wheat resistance to Pgt. Full article

Stressful effects on agriculture are of paramount importance in the 21st century. Water deficiency is considered a major constraint in crop succession, particularly for maize. Therefore, this study aimed to investigate the potential roles of brassinolide (BL) and silicon (Si) in mitigating biotic (incidence of pests and diseases) and abiotic stresses (naturally occurring water deficit) in maize grown after soybean harvest. The field experiments were conducted over two growing seasons on a Rhodic Haplustox in the Cerrado, Goiás, Brazil. A randomized complete block design was employed in a 5 × 2 factorial arrangement, with five BL doses (0.000, 0.050, 0.100, 0.150, and 0.200 mg L⁻¹) and two Si treatments (absence and presence), each with four replicates. BL was applied immediately when the soil moisture in the 0–0.20 m layer reached 16.25%, corresponding to the crop’s critical water threshold. This specific phenological point corresponded to the R₂ stage in the first off-season and the V₁₀ stage in the second off-season. Si applications were performed at the V₃ and V₈ stages. BL application enhanced growth, as well as physiological and metabolic performance by increasing protein synthesis and sugar content, thereby maintaining relative water content, sustaining antioxidant enzyme activity, and reducing lipid peroxidation under water-deficit conditions. The BL doses that achieved the highest yields were 0.149 mg L⁻¹ (R₂ stage) in the first off-season and 0.134 mg L⁻¹ (V₁₀ stage) in the second off-season. Si application effectively reduced pest damage and disease severity while improving plant water status. However, in the second off-season, a significant BL × Si interaction was limited to carotenoids, pheophytinization index, and disease severity. These results indicate that the combined use of BL and Si provides a promising strategy to enhance maize resilience by integrating BL-mediated yield promotion with Si-driven physical and biotic protection under adverse environmental conditions. Full article

This review investigates the multifaceted roles of nitrogen-fixing and phosphate-mobilizing bacteria in natural ecosystems, with a particular focus on their contributions to plant growth and sustainable soil management. These microbial communities contribute substantially to nutrient cycling by converting atmospheric nitrogen into plant-available forms and mobilizing insoluble phosphorus in soil, thereby enhancing soil fertility and promoting sustainable plant productivity. This review synthesizes current knowledge on the mechanisms underlying biological nitrogen fixation, phosphate solubilization and mineralization, and the production of plant growth–promoting metabolites. Particular attention is given to plant–microbe interactions and their role in improving nutrient availability, regulating plant physiological processes, and enhancing tolerance to abiotic stresses such as salinity, drought, and heavy metal contamination. The findings underscore the ecological importance of these plant-associated microbial communities and highlight their potential applications in biofertilizer and biostimulant development for sustainable agriculture and reduced dependence on synthetic fertilizers. Full article

Medicago ruthenica L., a superior forage crop within the genus Medicago (Fabaceae), is endowed with remarkable stress tolerance and an abundance of bioactive compounds, conferring significant ecological and forage value. Existing reviews primarily focus on a single research direction, and the most recent findings are dated, failing to cover breakthroughs at the molecular level. This paper systematically synthesizes the latest research progress in five key areas: genetic diversity and genomic studies, biotic stress responses, abiotic stress tolerance mechanisms (drought, salinity, and low temperature, etc.), utilization (including genetic breeding, ecological restoration, and forage development), and future research prospects. This review addresses critical gaps in existing literature, particularly regarding advances in genomic sequencing, biotic stresses, and research on stress-associated microorganisms. Research indicates that M. ruthenica exhibits extensive genetic diversity, and its genome contains numerous positive selection signals associated with stress resistance. It can tolerate multiple abiotic and biotic stresses through morphoplasticity, physiological metabolic regulation, and transcriptional regulation. Furthermore, its symbiosis with microorganisms such as rhizobia significantly enhances its stress tolerance. M. ruthenica demonstrates outstanding application potential in degraded grassland restoration and high-quality forage production. Future research should focus on mining stress-resistant genes, optimizing molecular breeding techniques, and integrating artificial intelligence into breeding practices. That will facilitate its transformation from a regional endemic resource to a commercially viable functional species, thereby providing robust support for ecological security and the sustainable development of grassland-based livestock husbandry in cold and arid regions. Full article