Plant Stress

Grapevine naturally endures stresses like heat, drought, and hypoxia. A recent study showed very low oxygen levels inside grape berries, linked to ethanol content. Other studies have established the link between ethanol and tolerance to various stresses: heat stress, drought, and high salinity. The causes of such a tolerance are not well understood. In our study, three-week-old Gamay calli, Vitis vinifera, were characterised for their endogenous oxygen levels and endogenous ethanol concentration. Subsequently, a transcriptomic study of these cells was conducted, 6 and 24 hours after treatment with 1 mM ethanol. After 6 hours, ethanol addition led to 386 differentially expressed genes, with a notable upregulation of genes related to heat response, especially small Heat Shock Proteins (sHSPs). Further experiments showed that ethanol priming in grape cells or in Arabidopsis seedlings reduced pigment and electrolyte leakage under heat stress, respectively. This study supports the idea that ethanol priming helps protect plants against heat stress and provides a valuable RNA-seq dataset for further research into the underlying mechanisms, sHSPs playing a potentially crucial role in this adaptive response.

Fluctuating extreme weather events, coupled with rising average temperatures, can severely impact grapevine physiology and yield. While biostimulants have been gaining acceptance as a short-terms tools to enhance grapevine resilience, their adoption is hindered by inconsistent efficacy, partly driven by unpredictable plant stress levels. Over two contrasting seasons, we integrated physiological, transcriptomic, and metabolomic analyses to investigate how a plant-based biostimulant modulates the sensibility of Vitis vinifera under varying intensities of heat, drought, and their combination. This panel of water status, ranging from -0.02 to -1.6 MPa, revealed that the physiological response induced by the biostimulant treatment alleviates water stress within a field-relevant hydraulic window located between -0.4 and -1.2 MPa. Moreover, moderate but constitutive reduction of growth parameters in biostimulant plants, suggests a trade-off between vegetative development and abiotic stress responses. Accordingly, gene expression analysis revealed an interaction between water availability and the plant response to the biostimulant, which suggest an activation of priming mechanisms. Metabolic profiling supported these findings, highlighting the central role of phenylpropanoid pathway modulation, together with adjustments in ROS dynamics and stress-related hormone responses, particularly abscisic acid. Overall, this work emphasizes the need for integrating detailed plant water status and leaf gas exchange to accurately evaluate biostimulant performances under abiotic stress.

Drought stress causes stomatal behavior change in most plants. Water deficit condition caused by drought is one of the most significant abiotic factors reducing plant growth, development, reproductive efficiency, and photosynthesis, resulting in yield loss. Maize (Zea mays L.) holds a superior position among all the cereals due to its versatile use in the food, feed, and alcohol industries. A common demonstrative feature of a complex network of signaling pathways led by predominantly abscisic acid under drought conditions is stomatal aperture reduction or stomatal closure, which allows the plant to reduce water loss through the stomatal pore and to sustain a long time on water deficit condition. This study analyses the stomatal density, stomatal closure percentages, and guard cell aperture reduction using a microscopy-based rapid & simple method to compare guard cell response & morphological variations of three hybrid maize varieties viz. BHM (BARI hybrid maize)-7, BHM-9, and BHM-13 developed by Bangladesh Agricultural Research Institute (BARI). A drought treatment was applied to all varieties at two different vegetative stages, vegetative stage 3 (V3) and V5, until they reach V4 and V6, respectively. After drought exposure at the V4 stage, the percentage of closed stomata of BHM-7, BHM-9, and BHM-13 was 21%, 23%, and 33%, respectively. The reduction in the guard cell aperture ratio of BHM-7, BHM-9, and BHM-13 was 14.83%, 10.92%, and 33.85%, respectively. At the V6 stage, for the second set of plants, the closed stomata of BHM-7, BHM-9, and BHM-13 were 18%, 21%, and 34%, respectively. The rate of reduction in guard cell aperture ratio of BHM-7, BHM-9, and BHM-13 was 5.52%, 2.48%, and 38.75%, respectively. Therefore, BHM-13 showed maximum drought adaptation capacity compared to BHM-7 and BHM-9 due to the highest percentage of closed stomata and the highest percentage of reduction in aperture ratio.

Salinity severely limits eggplant productivity, yet the transcriptional bases of tolerance to prolonged salt exposure remain incompletely understood. Here, we analyzed long-term salinity responses in two contrasting eggplant (Solanum melongena L.) genotypes from the G2P-SOL core collection, focusing on genotype-dependent transcriptional regulation under chronic stress. Plants were exposed to 200 mM NaCl for 23 days at the reproductive stage, and transcriptome profiling was performed at the end of the stress period. Physiological assessment and high-throughput phenotyping confirmed a strong divergence in water status and plant architecture between genotypes under salinity, providing a reference framework for transcriptomic interpretation. RNA-seq analysis revealed marked genotype-specific differences in transcriptional responses. While both genotypes activated a conserved salt-stress program involving redox homeostasis, proteostasis and growth repression, the tolerant genotype displayed a substantially broader and more coordinated transcriptional reprogramming. This response involved large-scale modulation of pathways related to translation and RNA metabolism, hormone signaling crosstalk, membrane transport, cell wall remodeling and oxidative stress management, together with the selective repression of growth- and signaling-related functions. In contrast, the sensitive genotype showed a more limited response dominated by defense- and damage-associated transcripts. Overall, these results indicate that long-term salt tolerance in eggplant is associated with genotype-specific transcriptional reprogramming superimposed on a shared basal stress response. This work highlights regulatory pathways and candidate genes potentially relevant for breeding strategies targeting salt resilience.

The effects of moisture content (MC) and storage temperature (ST) on seed longevity have been modeled for many species. In contrast, our understanding on the combined effects of MC and ST on dormancy release (DR) in "dry" orthodox seeds is still insufficient to build robust predictive models. We used freshly harvested, dormant sunflower achenes to explore the effects of MC (4-10%) in combination with a wide range of ST (-18{degrees}C to +30{degrees}C) on DR dynamics, embryo responsiveness to abscisic acid (ABA) and deterioration indicators. Storage temperatures allowing full DR were inversely related to achene MC, ranging from >25{degrees}C for MC4% to sub-zero temperatures for MC10%, resembling a phase diagram. Rates of DR were plotted along a RH gradient. Combinations of MCxST optimal for DR were between ca. 40-60%RH. Increasing RH from 60 to 80% inhibited DR. Higher RH>80-85% promoted partial DR together with rapid ageing. We suggest that reactions promoting full DR are favored alongside a physical (glassy) transition and are not oxidative. We propose biophysical coordinates to guide future studies on the mechanisms involved in DR, but also to develop predictive models useful to define post-harvest conditions that maximize sunflower seed quality. Highlights{square} The effects of moisture content (MC) and storage temperature (ST) on dormancy release and deterioration were investigated in sunflower achenes using a factorial design. {square}Dormancy release was promoted by MCxST combinations in equilibrium with a RH between 40 and 60% and was delayed outside this range. {square}Storage temperatures optimal for dormancy release were inversely related to achene MC, ranging from >25{degrees}C for MC4% to sub-zero temperatures for MC10%, resembling a phase diagram. {square}Dormancy release and ageing are promoted within distinct, non-overlapping regions along the RH gradient supporting different types of reactions for each process.

Low temperature stress causes significant damage to the strawberry plant. During cold stress, plants undergo morphological and physiological changes often regulated at the genetic and/or epigenetic levels. Some strawberry cultivars are more cold-hardy than others. Using the diploid woodland strawberry as a model, we analyzed the effects of cold acclimation on methylome and transcriptome dynamics in the crowns and leaves of three ecotypes with contrasting cold tolerance. Alta, which was the most cold-tolerant ecotype, exhibited the highest genetic and epigenetic plasticity in response to cold. CHH-context methylation dominated the differentially methylated regions (DMRs) with more hypomethylation in crowns and hypermethylation in leaves. CG methylation was enriched in gene bodies, while non-CG methylation was prevalent in upstream and downstream regions. Our study revealed that less than a quarter of differentially methylated genes (DMGs) showed changes in transcript accumulation levels. This finding indicates that universal cold response in Fragaria vesca, as reflected by gene expression, cannot be mechanistically attributed to DNA methylation. The majority of differentially expressed differentially methylated genes (DEDMGs) were ecotype- and tissue-specific. Enrichment analysis revealed that these genes were involved in pathways related to stress tolerance, such as carbohydrate metabolism, lipid metabolism, ATP hydrolysis, and cellular detoxification. Each ecotype responded to cold through mobilization of its own set of differentially expressed genes (DEGs), DMGs, and DEDMGs, and variation in expression and methylation patterns exhibited by Alta, FDP817, and NCGR1363 suggest that cold signaling processes and survival depend on the tissue, ecotype, and geographical origin of the plants exposed to cold stress. Therefore, this study highlights the potential of both genetic markers and epialleles as molecular markers for the development of cold-tolerant octoploid strawberry cultivars that are better suited for propagation in Nordic climates.

BackgroundAlginate oligosaccharides (AOS) are emerging biostimulants known to modulate plant defense and growth hormones. However, the influence of AOS chain length--defined by degree of polymerization (DP)--on multiple phytohormones in wheat under pathogen stress has not been systematically evaluated. MethodsWheat seedlings (cv. Bobwhite) were pretreated 24 h before inoculation with Botrytis cinerea using AOS fractions of DP 2-9 (100 mg L-{superscript 1}). Leaves were harvested 48 h post-inoculation, and seven hormones--jasmonic acid (JA), salicylic acid (SA), indole-3-acetic acid (IAA), cytokinins (CTK), abscisic acid (ABA), ethylene (ET), and gibberellins (GA)--were quantified by LC-MS/MS (JA, SA, IAA, CTK, ABA, GA) or GC-FID (ET). Data represent mean fold-changes (n = 5 biological replicates) relative to untreated controls, with significance assessed by two-tailed t-tests (p < 0.05). ResultsAOS effects were highly DP-dependent. JA peaked at DP 4 (2.50-fold; p = 3.12 x 10-) then declined at higher DPs. SA induction was greatest at DP 3 (3.20-fold; p = 8.90 x 10-). IAA and GA both maximized at DP 5 (2.30-fold; p = 5.67 x 10- and 2.34-fold; p = 7.24 x 10-, respectively). CTK and ABA each showed highest accumulation at DP 6 (2.40-fold; p = 4.12 x 10- and 3.00-fold; p = 2.34 x 10-). In contrast, ET was most strongly suppressed by DP 7 (0.416-fold; p = 5.54 x 10-). All DP treatments differed significantly from control (p < 0.05). ConclusionsThe degree of polymerization critically governs AOS-mediated modulation of phytohormones in wheat under B. cinerea stress. Mid-range oligomers (DP 4-6) optimally enhance defense-related hormones (JA, SA, ABA, CTK), while slightly longer chains (DP 7) most effectively suppress ET. These insights enable the tailored selection of AOS fractions to bolster disease resistance and growth in cereal crops.

Several studies assessed the potential of salts and plant extracts as sustainable, eco-friendly phytosanitary products in plant protection. Here, we examined the efficacy of Generally Recognized as Safe (GRAS) salts sodium benzoate (SBE) and sodium bicarbonate (SBI) used alone or in combination with a twig extract from eastern hemlock (EH) against the bacterial pathogen Pseudomonas syringae pv. tomato DC3000 (Pst DC3000). The antimicrobial activity of the three products, and their ability to bolster host plant natural defenses, were assessed using the Arabidopsis-Pst DC3000 pathosystem as a model. RT-qPCR and leaf staining assays on a transgenic Arabidopsis line engineered to express reporter protein {beta}-glucuronidase under the control of pathogen-inducible promoter PR1 showed both GRAS salts and the EH extract to trigger the expression of salicylic acid (SA)-inducible genes. Salt- and EH extract-treated plants exhibited callose deposits in leaf tissue, further pointing to the induction of the SA signaling pathway and suggesting the establishment of a physical barrier in the leaf apoplast upon treatment. Direct toxicity measurements and a bacterial infection assay in growth chamber showed both GRAS salts and the EH extract to inhibit Pst DC3000 growth and Arabidopsis leaf colonization. Toxicity assays also revealed complementary, additive effects between the two salts and the EH extract in their detrimental effect against the pathogen, as evidenced by reduced minimum inhibitory concentrations when used in combination. Interestingly, SBE and SBI strongly delayed leaf senescence following infection, either alone or combined with the EH extract. Together, these findings confirm the potential of SBE, SBI and the EH twig extract as both toxic compounds against Pst DC3000 and natural defense stimulators in Arabidopsis. They also highlight the potential of GRAS salt and plant extract combinations as a sustainable alternative to chemical pesticides in plant pathogen management.

During drought, numerous compounds accumulate in plant tissues, but their physiological roles remain unclear - they may function as osmolytes, osmoprotectants, or merely arise as by-products of stress-induced metabolic shifts. We developed an experimental approach to link accumulation patterns with specific functions, using Scots pine (Pinus sylvestris L.) saplings subjected to water deprivation and subsequent rewatering as a model system. We monitored changes in relative water content (RWC) and osmotic adjustment dynamics, employed untargeted primary metabolite profiling for preliminary screening of compounds correlated with water status, and performed quantitative GC-MS and LC-MS analyses of selected metabolites. Major inorganic cations (K, Ca{superscript 2}, Mg{superscript 2}) were also quantified to assess their potential roles. Our results revealed that tryptophan, valine, and lysine - though generally present in low abundance - exhibited selective accumulation under severely reduced RWC ([&le;] 70%), suggesting their involvement as osmoprotectants. Major organic acids, particularly shikimic acid, showed trends consistent with osmotic adjustment. Notably, neither sucrose nor inorganic cations appeared to function as primary osmolytes in this context. The proposed approach offers a viable strategy for identifying compounds involved in plant adaptation to water deficit, with potential applications in breeding programs aimed at improving drought tolerance. HighlightsAn approach to identify osmolytes and osmoprotectants was implemented Accumulation of Trp, Val and Lys was consistent with their role in osmoprotection Osmotic adjustment relied predominantly on organic acids than on inorganic ions Monosaccharides but not sucrose correlates with changes in needle water status

X-ray fluorescence spectroscopy (XRF) is a powerful technique for the in vivo assessment of plant tissues. However, the potential X-ray exposure damages might affect the structure and elemental composition of living plant tissues leading to artefacts in the recorded data. Herein, we exposed soybean (Glycine max (L.) Merrill) leaves to several X-ray doses through a polychromatic benchtop microprobe X-ray fluorescence spectrometer, modulating the photon flux by adjusting either the beam size, focus, or exposure time. The structure, ultrastructure and physiological responses of the irradiated plant tissues were investigated through light and transmission electron microscopy (TEM). Depending on the dose, the X-ray exposure induced decreased K and X-ray scattering intensities, and increased Ca, P, and Mn signals on soybean leaves. Anatomical analysis indicated necrosis of the epidermal and mesophyll cells on the irradiated spots, where TEM images revealed the collapse of cytoplasm and cell-wall breaking. Furthermore, the histochemical analysis detected the production of reactive oxygen species, as well as inhibition of chlorophyll autofluorescence in these areas. Under certain X-ray exposure conditions, e.g., high photon flux and exposure time, XRF measurements may affect the soybean leaves structures, elemental composition, and cellular ultrastructure, and induce programmed cell death. These results shed light on the characterization of the radiation damage, and thus, help to assess the X-ray radiation limits and strategies for in vivo for XRF analysis. HighlightBy exposing soybean leaves to several X-ray doses, we show that the characteristic X-ray induced elemental changes stem from plants physiological signalling or responses rather than only sample dehydration.

Alfalfa (Medicago sativa L.) is frequently constrained by drought and salinity during cultivation and production. This study aimed to investigate the differential response characteristics and underlying physiological and ecological mechanisms of alfalfa during the germination stage under drought stress, bicarbonate stress, and their combined effects. Twelve alfalfa varieties were subjected to germination tests using PEG-6000 to simulate drought stress (0-20%) and NaHCO{square} to simulate bicarbonate stress (0-30 mM). Based on the semi-inhibitory concentrations and phenotypic indices observed under single-stress conditions, a combined stress treatment was designed. The subordinate function method was employed to comprehensively evaluate the variations in stress responses among the twelve alfalfa varieties during the germination stage. Additionally, this study explored the physiological and ecological response mechanisms of drought-tolerant, salt-tolerant, and drought-salt-sensitive varieties. Among the 12 alfalfa varieties, WL363HQ has the strongest drought and salt tolerance, while WL319HQ is the most sensitive to drought and salt stress. Based on this, the varieties can be classified into drought-tolerant, salt-tolerant, and sensitive categories. At low concentrations, the drought-salt combination shows antagonism (salt alleviates drought inhibition); at high concentrations, it turns into synergy, and the inhibitory effect is amplified.WL363HQ adapts to the combined stress by maintaining stable SOD activity and gradually accumulating soluble sugar; WL319HQ shows sensitivity due to fluctuating SOD, membrane lipid peroxidation, and uncontrolled soluble sugar.

Though relatively little is understood of adaptation, physiological and metabolic changes of Stevia rebaudiana under exposure to salinity stress, it is hypothesized that exogenous application of potassium (K+) could elevates the salinity tolerance through ions homeostasis. Thus, an experiment was conducted with twenty treatment combinations comprising four salinity levels (irrigation with normal water as control and three level of NaCl at 40, 80 and 120 mM) and five different concentrations of KNO3 (0.0, 2.5, 5.0, 7.5, and 10.0 g L-1). Dry leaf yield was not negatively affected with mild salinity (40 mM). However, the detrimental effects were observed at moderate and higher salinity levels (80 and 120 mM). The uptakes of K+, Ca2+, and N were significantly reduced at higher salinity level, whereas accumulations of Na+ and Cl- ions in plant tissues were substantially increased. Proline content in leaf was also increased significantly (P[&le;]0.05) in response to salt stress. Among the foliar application, KNO3 at 5.0 gL-1 registered significantly (P[&le;]0.05) higher dry leaf yield compared with control. Exogenous application of K+ under moderate salinity stress maintained ion balance in cytosol, particularly K: Na. Thus, the salinity tolerance of stevia can be elevated to some extent through exogenous application of K+.\n\nHighlightThe detrimental effects of moderate and higher salinity levels on growth and dry leaf yield of stevia were observed. However, tolerance level can be elevated through exogenous application of KNO3.

Salt tolerant is strongly related to potassium (K+) retention in plant tissues under salt stress conditions. However, it is unclear for different Echinacea species. So, mechanistic basis of four Echinacea species (i.e. Echinacea purpurea, Echinacea angustifolia, Echinacea pallida, and Echinacea sanguinea) to salinity stress tolerance, and K+ retention were assessed in the present study. Non-invasive microelectrode ion flux measuring, DHAR and MDHAR activities, and pharmacological measurements were performed based on the standard methods. Ion flux measurements revealed higher K+ efflux in E. pallida and E. sanguinea species compared to the E. purpurea and E. angustifolia species in the elongation zone. Higher salinity-induced H+ efflux was found in the elongation zone than mature zone. However, E. angustifolia and E. purpurea had more Ca2+ influx compared to E. pallida and E. sanguinea species. Net K+ efflux decreased (> 90%) in the presence of TEA and GdCl3. Increasing of Ca2+ uptake and K+ loss in four Echinacea species roots were found in the presence of 0.3 mM Cu/Ascorbate (Cu/Asc). The significant role of H+-ATPase in H+ efflux was demonstrated by Sodium orthovanadate. Ultimately, the physiological properties of Echinacea species have a critical role in salinity-resistant/sensitive differences. Future scientific understanding of Echinacea species physiognomies may be necessary for better understanding of the plant behavior to salinity stress. One-sentence summaryHigher K+ efflux in E. pallida and E. sanguinea species as a result of NaCl and ROS act as a metabolic switch to save energy for adaptations and repairs in salinity stress conditions.

Increasing frequency of drought under climate change threatens crop production and intensifies pest pressures, yet the interactive effects of drought and herbivory on plant metabolism and ecological outcomes remain incompletely understood. We subjected sugar beet (Beta vulgaris) plants to moderate and high drought, alone or with infestation by the beet leaf miner (Pegomya cunicularia), and analyzed plant physiology, central metabolites, and volatile organic compound (VOC) emissions. Drought alone reduced growth and photosynthetic efficiency, while combined stress led to accentuated metabolic reprogramming, including increased amino acids and organic acids, and a concurrent suppression and alteration of VOC emissions, especially in plants affected by high drought and leaf mining. The resulting changes in VOC blends reduced plant attractiveness to ovipositing females, leading to fewer eggs laid on severely stressed plants. Contrastingly, moderate drought generated a nutrient-rich environment: larvae feeding on these plants exhibited the highest growth rates, larger pupae and adults, and increased feeding damage. High drought strongly limited both plant water content and larval development. These findings reveal a stress-dependent tradeoff between enhanced leaf nutritional quality and reduced host detectability, underscoring the importance of integrating multi-stress plant biology for future pest management and crop resilience. HighlightCombined drought and herbivory in sugar beet plant triggered stress-intensity-dependent trade-offs between leaf nutritional quality and volatile emissions, affecting beet leaf miner performance and oviposition--highlighting how multi-stress interactions shape plant-insect dynamics. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=111 SRC="FIGDIR/small/708914v1_ufig1.gif" ALT="Figure 1"> View larger version (28K): org.highwire.dtl.DTLVardef@1d92105org.highwire.dtl.DTLVardef@70693org.highwire.dtl.DTLVardef@140dc82org.highwire.dtl.DTLVardef@14cf411_HPS_FORMAT_FIGEXP M_FIG Graphical Abstract C_FIG

Methylglyoxal (MGO), toxic byproduct of glycolysis, acts as a signaling molecule at low levels, but its over-accumulation during drought stress disrupts redox balance and accelerates cell death. Contrarily, melatonin maintains redox balance, particularly during stress. The redox status and MGO level might differ in drought-sensitive and drought-tolerant varieties, so shall the melatonins effect. The study evaluated the effect of melatonin-priming on MGO detoxification and autophagy during polyethylene glycol (PEG)-induced drought stress during seed germination in drought-sensitive (L-799) and drought-tolerant (Suraj) varieties of upland cotton. Melatonin-priming increased endogenous melatonin content, reduced MGO accumulation and advanced glycation end-products (AGEs), and downregulated the expression of MGO biosynthesis genes in L-799 under stress. The expression and activities of glyoxalases and non-glyoxalases were upregulated, showing melatonins effectiveness in MGO detoxification. Additionally, priming upregulated the expression of TPI1, PGK5, and PK1 and downregulated HK3 expression, allowing better conversion of glucose to pyruvate, leading to reduced MGO in L-799. The downregulation of necrosis-related genes with reduced cell death in L-799 shows the potential of priming in maintaining cell viability under stress. Furthermore, upregulated expression of SnRK1.1, SnRK2.6 genes and KIN10 protein levels, with enhanced autophagy markers (ATGs, MDC-stained bodies, lipidated-ATG8), confirmed improved autophagy in melatonin-primed L-799 under stress. Despite lowered ABA, melatonin-mediated MGO homeostasis likely activated MAPK6, inducing autophagy independent of ABA in stressed plants. Conversely, Suraj, with higher endogenous melatonin and inherent stress tolerance, showed limited response to priming. Thus, the study illustrates melatonins role in regulating MGO homeostasis and autophagy under drought stress in cotton.

O_LIIncreasing frequency, intensity, and duration of heat waves (HWs) threaten agricultural production globally by constraining physiological function and fruit production. Supplemental irrigation mitigates heat stress in grapevine and other woody perennial crops, yet water scarcity necessitates optimized irrigation strategies during extreme heat. C_LIO_LIWe conducted a three-year field trial in a commercial Cabernet Sauvignon vineyard, applying differential irrigation only before and during naturally occurring HWs: baseline (50% ET), moderate (90-120% ET), and high (120-180% ET). We monitored water potentials, leaf gas exchange, canopy temperature, yield, and berry composition. C_LIO_LIBaseline irrigation consistently reduced net photosynthesis, stomatal conductance, and leaf cooling capacity during HWs. Moderate supplemental irrigation maintained gas exchange, transpiration, and leaf temperature, mitigating yield losses. Excessive irrigation beyond moderate levels provided no additional physiological benefit and decreased crop water use efficiency and berry quality. C_LIO_LIOur results demonstrate that targeted, event-based irrigation sustains grapevine physiological performance and fruit production under extreme heat, whereas both insufficient and excessive water negatively affect carbon assimilation, stomatal regulation, and crop productivity. These findings emphasize the importance of aligning water management with heat event timing to preserve vine function, optimize water use, and maintain yield and fruit quality in water-limited regions. C_LI

Drought stress poses a significant threat to agricultural productivity, particularly in regions with limited water availability. This study delves into the drought response in a multiparental interspecific tomato MAGIC population (ToMAGIC), developed by intercrossing Solanum pimpinellifolium (SP) and S. lycopersicum var. cerasiforme (SLC). A core collection of 139 recombinant lines, selected for their genetic diversity, was evaluated under both control and water stress conditions over two consecutive years. Phenotypic data were collected for 25 traits, including vegetative growth, flowering, fruit production, and physiological traits, providing a comprehensive assessment of drought response. Genome-wide association studies (GWAS) identified 15 significant genomic regions associated with drought response across eight chromosomes, highlighting key loci related to growth, earliness, fruit set, and physiological traits such as stomatal conductance and proline accumulation. Transgressive lines, such as S5_T_600 and S5_T_601, which exhibit enhanced drought resilience compared to the parental lines, were identified through genomic assisted selection, highlighting their potential as valuable breeding materials. The study emphasizes the importance of the ToMAGIC population in uncovering the polygenic nature of drought response. These findings offer valuable insights for developing drought-resilient tomato cultivars supporting agricultural sustainability in water-limited environments.

Regulation of sodium homeostasis is crucial for plant response to salinity conditions. Here we report on the genetic and physiological characterization of two tomato allelic mutants, sodium gatherer1-2 (sga1-2), which exhibit pronounced chlorosis and hyperhydration under salt stress. Mapping-by-sequencing revealed that mutant phenotype resulted from mutations in the SlRbohG gene, and CRISPR/Cas9 knockouts of this gene gave phenocopies of the sga1-2 mutants. Physiological analyses showed that sga1-2 salt hypersensitivity is linked to an increase of Na+ and water transport from roots to shoots, which explains their extreme chlorosis and hyperhydration under salinity conditions. At the molecular level, SlPIP2;12 gene, an aquaporin down-regulated in the WT under salt stress, was overexpressed in the sga1-2 mutants, which could enhance water transport to the shoot. Also, sga1-2 mutants exhibited a significant reduction in the expression of key sodium transporters, thus modifying the normal distribution of Na+ in tomato plant tissues. Furthermore, treatment of WT plants with the NADPH oxidase inhibitor DPI prevented H2O2 production in response to salinity, resulting in elevated Na+ accumulation in the shoot and reduced expression of the SlHKT1;2 gene in root. Altogether, our results show that SlRbohG plays a central role in salt tolerance through ROS-mediated signaling. HIGHLIGHTLoss of function of tomato SlRbohG gene leads hypersensibility to salt stress due to increased Na+ and water transport from root to shoot.

Indica rice, being a tropical crop, is highly sensitive to cold temperature. Cold stress affects vegetative growth, photosynthetic efficiency, along with reproductive features. Genetic resource screening in diverse landraces is an approach for identifying cold-tolerant traits. Here, we have characterised a boro germplasm, CB1, with an efficient germination rate and growth vigour when treated at chilling temperatures. CB1 seedlings show a higher survival rate compared to IR36 when subjected to prolonged chilling stress. Biochemical analyses indicated efficient ROS modulation, higher chlorophyll content, enhanced photosystem II efficiency and unique stomatal traits, leading to higher relative water content in CB1 plants during stress and recovery. Transcriptome analysis supported upregulation of chlorophyll biosynthesis, photosystem, & light harvesting complex and ROS scavenger genes in CB1 seedlings. Interestingly, high D1 protein turnover in CB1 promotes damage-repair of PSII for efficient photosynthesis. Furthermore, key transcription factors for stomatal development and expression of photosynthetic genes were upregulated in CB1 during stress recovery. Notably, higher expression of OsGLK1 and enrichment of GLK1 targets were observed in CB1 plants during chilling stress and recovery. Taken together, our results suggested that CB1 plants exhibit cold tolerance by modulating photosynthesis efficiency and stomatal behavior for better adaptability and survival against chilling temperature. HIGHLIGHTSThe efficient photosynthetic recovery, active ROS scavenging system and maintenance of water content through regulating stomatal traits, enhance the survival of indica germplasm CB1 against chilling stress.

Rice (Oryza sativa) is highly sensitive to salinity, yet the metabolic mechanisms underlying salt tolerance remains incompletely understood. In this study, we performed leaf tissue-specific untargeted metabolomic profiling of the salt-tolerant introgression line JN100 (JN), its donor parent Nona Bokra (NB), and its recurrent parent Jupiter (JU) to characterize metabolic responses to salt stress. Comparative analysis identified differentially accumulated metabolites (DAMs) spanning diverse chemical classes, including amino acids, sugars and carbohydrates, lipids, organic acids, cofactors, electron carriers, and nucleotides. Under salt stress (SS), 201 DAMs (89 upregulated and 112 downregulated) were detected in JN relative to JU. Notably, metabolites such as allantoin, glycitin, nicotinamide ribotide, D-arabinono-1,4-lactone, violanthin, L-methionine S-oxide, ribitol, lysine, rutin, glutamine, pantothenic acid, and quinic acid, showed significant differential accumulation. Pathway enrichment analysis revealed significant enrichment of arginine biosynthesis, purine metabolism, and alanine, aspartate, and glutamate metabolism, indicating extensive reprogramming of nitrogen and energy-associated metabolic pathways under salinity stress. Integration of transcriptomic and metabolomic datasets from the SS experiments further identified ten differentially expressed genes (DEGs) associated with the metabolite network in the JN vs. JU comparison. Among these, OsDHQDT/SDH, OsFd-GOGAT, phenylalanyl-tRNA synthetase, OsP5CS1, OsP5CS2, and a pyridoxal phosphate-dependent transferase were linked to metabolites involved in shikimate, amino acid, and proline metabolism. Collectively, these results demonstrate that salinity tolerance in rice is associated with coordinated transcriptional and metabolic reprogramming that supports oxidative stress mitigation and adaptive stress responses.