Search Results (102)

Fibrillins (FBNs) are conserved plastid-associated proteins implicated in plant development and abiotic stress responses; however, their roles in maize remain unclear. In this study, through a genome-wide bioinformatic analysis, we identified 14 ZmFBN genes in the maize genome and characterized their phylogeny, chromosomal distribution, gene structure, conserved motifs, and promoter cis-elements. ZmFBN members were grouped into several subfamilies that all retain a conserved PAP_fibrillin domain, whereas the variation in exon–intron organization, motif composition, and regulatory elements suggests functional diversification. Expression profiling revealed pronounced tissue-preferential patterns, with many genes highly expressed in leaves and reproductive tissues, and distinct responses to drought, salt, heat, and cold stresses. qRT-PCR assays showed that ZmFBN8 and ZmFBN9 are strongly induced by both salt and PEG-simulated drought, ZmFBN2 and ZmFBN5 are predominantly drought-responsive, and ZmFBN11 is mainly activated by salt. Genome-wide association analysis further detected significant loci near ZmFBN1 and ZmFBN4, whose allelic variants are associated with the survival rate under drought and with key agronomic traits, including the tassel branch number, flowering time, ear diameter, and kernel length. These results demonstrate that ZmFBN genes make diversified contributions to maize growth, development, and stress adaptation and highlight several members as promising targets for functional studies and the molecular breeding of stress-tolerant maize. Moreover, selection pressure analysis indicated ZmFBN7 experienced relaxed purifying selection, and ZmFBN12 underwent positive selection, which drives the functional diversification of the ZmFBN family during maize evolution. Full article

The RING-type E3 ubiquitin ligase plays a significant role in plant responses and adaptations to abiotic stresses such as drought. However, few studies have explored the role of E3 ubiquitin ligases in potato drought stress, especially DRIP1. In this study, 172 StHCa genes were identified across the potato genome. These genes were unevenly distributed on twelve chromosomes and divided into six subclades (group I–VI). The molecular weight of potato HCa proteins ranges from 5445.38 to 143,293.69 Da. More than half of them are acidic proteins and most are unstable. There are 161 hydrophilic proteins, and the subcellular localization analysis indicated that they were mainly located in the nucleus. The co-linearity analysis of StHCa genes showed that 172 genes underwent 40 tandem duplications and 28 segmental duplication events. Potato and tomato share a recent common ancestor and exhibit highly similar evolutionary trajectories. Promoter sequence analysis of the StHCa family identified abundant cis-acting elements associated with light signal transduction, hormone responses, plant growth and development, and abiotic stress responses. These results suggest that the StHCa genes may play important regulatory roles in different environmental signals and developmental stages. Expression profiling revealed that StDRIP1 exhibited higher transcript levels in potato roots than in stems and leaves, and its expression was significantly induced by drought stress. Physiological phenotyping demonstrated that StDRIP1-overexpressing (OE) plants displayed reduced root growth compared with wild-type (WT) plants, with decreases in root length, total root area, total root volume, and root vitality. Under 20% PEG-6000-simulated drought stress, the root expression level of StDRIP1 was higher in OE lines than in WT plants. Furthermore, StDRIP1 overexpression suppressed the activities of antioxidant enzymes (POD, CAT, and SOD) and weakened their osmotic adjustment ability by reducing proline (Pro) accumulation. At the late stage of stress treatment (9 h), the SOD, POD, and CAT activities of OE plants were 5.0%, 19.9%, and 25.1% lower than those of WT plants, respectively. These physiological alterations exacerbated oxidative damage, as evidenced by increased malondialdehyde (MDA) content and elevated electrolyte leakage in OE plants. In summary, this study comprehensively characterized the StHCa gene family in potato, providing a valuable theoretical basis for elucidating the functional mechanism of StDRIP1 in modulating drought stress responses. Collectively, StDRIP1 acts as a negative regulator of potato drought tolerance through two primary mechanisms: (1) repressing root growth and weakening root vitality, thereby reducing the water absorption capacity of roots; and (2) diminishing antioxidant enzyme activities and impairing osmotic homeostasis, which further exacerbates oxidative damage under drought stress. Full article

The CSM-CROPGRO-Lentil model (DSSAT v4.8.5) was calibrated and validated for 43 ICARDA lentil genotypes across three growing seasons (2019–2022) under semi-arid rainfed conditions in southeastern Türkiye. Calibration against the 2019–2020 season yielded excellent performance for phenological traits (anthesis date nRMSE = 0.8%; maturity date nRMSE = 1.2%), thousand-seed weight (nRMSE = 1.6%), and good performance for grain yield (nRMSE = 19.3%; d = 0.935) and biological yield (nRMSE = 11.1%; d = 0.941). Phenological simulations remained robust (anthesis and maturity dates nRMSE = 6.8% and 1.6%), but grain and biological yield simulations failed (nRMSE = 43.0–74.7%) with opposing bias directions in both validation seasons. Spearman rank correlation collapsed to non-significant levels in both validation years (rho = −0.020 and +0.263), indicating a loss of genotype-ranking capacity, in which only three accessions (G37, G3695, and G21151) maintained simulation error below 40% across both drought seasons. Model bias was not significantly associated with PEG-derived drought tolerance classifications, based on composite stress tolerance index-based reclassification with balanced group sizes (n = 5 vs. n = 5; Mann–Whitney p ≥ 0.548), suggesting that limitations in species-level water stress response functions may have contributed to model failure, although the potential influence of interannual differences in soil hydraulic properties cannot be excluded. Late-maturing genotypes were simulated significantly more accurately than early and mid-maturing genotypes in 2021–2022 (Kruskal–Wallis p = 0.013), while large-seeded genotypes showed disproportionately greater underestimation in 2020–2021 (rho = −0.410, p = 0.006). These findings demonstrate that CROPGRO-Lentil reliably simulates phenological diversity under favorable conditions but requires genotype-specific drought stress parameterization and improved seed-filling dynamics to support genotype evaluation under increasingly variable semi-arid moisture regimes. Full article

Drought and water deficit have severely restricted melon (Cucumis melo L.) production in Xinjiang, and large-scale systematic evaluations of drought tolerance at the germination stage are still extremely limited. Physiological and biochemical indicators related to the germination stage, including osmotic adjustment substances and antioxidant enzyme activities, have not yet been incorporated into prediction models for the rapid identification of germplasm drought resistance. To address these research gaps, this study selected 60 accessions of local melon germplasm resources in Xinjiang and used polyethylene glycol (PEG) solutions at four different concentrations (0%, 10%, 20% and 30%) to simulate drought stress conditions. Drought tolerance was evaluated to develop a method for the rapid screening of drought-tolerant germplasms. The findings demonstrated that PEG stress significantly suppressed seed germination and had both stimulatory and inhibitory effects on radicle growth. With the increase in PEG concentration, germination indices consistently exhibited a downward trend. Under 10% PEG treatment, the variation among different germplasms was relatively small, while 30% PEG completely inhibited seed germination. Notably, 20% PEG fell within the semi-lethal concentration range for all tested germplasms and yielded the maximum coefficient of variation for germination rate, which could maximally differentiate the drought resistance differences among germplasms. Therefore, 20% PEG was determined to be the optimal screening concentration. Under 20% polyethylene glycol (PEG) stress, the degree of membrane lipid peroxidation (malondialdehyde, MDA), contents of osmotic regulators (proline, Pro; soluble protein, SP), and activities of antioxidant enzymes (superoxide dismutase, SOD; peroxidase, POD; catalase, CAT; ascorbate peroxidase, APX) in the radicles of melon germplasms were universally elevated. However, the variation ranges and trends of biochemical indices among different germplasms exhibited significant differences. The proline content of melon accessions with strong drought resistance increased, the malondialdehyde (a product of membrane damage) was low, and the enzyme activities increased significantly. The proline content of non-drought-tolerant melon accessions increased less, malondialdehyde accumulated in large amounts, and the activity of some protective enzymes decreased. Correlation analysis demonstrated that Pro exerted a synergistic effect in conjunction with antioxidant enzymes (SOD, CAT) to mitigate drought stress. Cluster analysis classified the germplasm into 14 high-tolerance types, 10 medium-tolerance types, and 9 low-tolerance types. Based on extreme germination phenotypes, 27 germplasms were identified as drought-sensitive types. A prediction model for drought tolerance was established via stepwise regression: D = −0.309 + 0.053 × Pro (proline content) + 0.319 × RL (radicle length) + 0.469 × MDA (malondialdehyde) + 0.137 × SOD (superoxide dismutase), with four core indicators (RL, MDA, Pro, SOD) identified. These findings provide a scientific basis and technical support for drought tolerance breeding, parental selection, and large-scale, precise, and rapid drought tolerance screening of melon germplasms in the arid regions of Xinjiang. Full article

Chemical regulators play an important role in alleviating abiotic stress during seed germination and early seedling establishment, providing a low-cost and effective solution for crop production under stress conditions. The seed germination stage is critical for crop establishment under drought stress. Proso millet (Panicum miliaceum L.) is relatively drought-tolerant during later growth stages but remains sensitive during seed germination and early seedling establishment. In this study, two P. miliaceum varieties (‘Yumi 2’ and ‘Yumi 5’) were used as materials. Seeds were soaked with 2,4-epibrassinolide (EBR) at concentrations of 0, 0.01, 0.1, 0.5, and 1 μmol·L⁻¹, and then germinated under polyethylene glycol (PEG-6000) solutions at 0%, 15%, and 20% (w/v) to simulate drought stress. Drought stress progressively reduced seed germination potential, germination percentage, germination index, and vigor index, while increasing mean germination time and decreasing germination synchrony. EBR soaking, particularly at 0.01 μmol·L⁻¹, consistently alleviated the above inhibitory effects. Under 20% PEG stress, 0.01 μmol·L⁻¹ EBR increased the germination potential of ‘Yumi 5’ to 82% and significantly improved the germination percentage of both varieties. Compared with the control, low concentrations of EBR (0.01 and 0.1 μmol·L⁻¹) increased the germination synchrony of ‘Yumi 2’ by up to 89.5% and 93.6%. Under 20% PEG stress, the germination synchrony of ‘Yumi 2’ treated with 0.01 μmol·L⁻¹ EBR was 54.7% higher than that of the control. EBR treatment increased α-amylase activity, with the highest activity observed at 0.01 μmol·L⁻¹ under non-stress conditions, and it maintained relatively high activity under drought stress, especially in ‘Yumi 5’. The two varieties exhibited genotype-dependent response differences: ‘Yumi 5’ responded to a wider range of EBR concentrations under drought stress, whereas ‘Yumi 2’ showed a selective response. Soaking seeds with 0.01 μmol·L⁻¹ EBR is a promising pre-sowing treatment strategy for improving seedling establishment of P. miliaceum under drought-prone conditions. In summary, this study provides a low-cost and easily applicable hormone soaking method that can be directly used to enhance the early drought tolerance of cereal crops. Furthermore, this strategy may offer practical guidance for improving seedling techniques in medicinal plants facing similar drought stress during propagation, thereby supporting sustainable agricultural production in water-deficient regions. Full article

Astragalus mongholicus is one of the original plant species of the medicinal herb Astragali Radix as recorded in the Chinese Pharmacopoeia, possessing significant medicinal value and being widely utilized worldwide. TCP transcription factors constitute a plant-specific transcription factor superfamily that plays essential regulatory roles in vegetative growth, organ development, and abiotic stress responses. However, the TCP gene family in A. mongholicus has not yet been systematically investigated, and its functional characteristics remain largely unknown. In this study, based on genome-wide data, a total of 25 AmTCP genes containing complete TCP domains were identified in A. mongholicus, and their protein properties, sequence alignment, gene structures, and phylogenetic relationships were systematically characterized using comprehensive bioinformatics tools. Promoter cis-element analysis revealed that the AmTCP promoter regions are enriched in cis-elements associated with hormones, light, and abiotic stresses (drought and salinity), suggesting their potential involvement in multiple signaling cascades. Furthermore, transcriptomic profiling combined with qRT-PCR validation demonstrated that AmTCP genes exhibit tissue-specific expression patterns and differential responses to salt stress and polyethylene glycol (PEG)-simulated drought stress. Notably, AmTCP3, AmTCP8, AmTCP11, AmTCP17, and AmTCP19 displayed tissue- and time-dependent alterations in expression under stress conditions, with AmTCP17 and AmTCP19 showing the most pronounced responsiveness. Collectively, our findings systematically elucidate the fundamental molecular characteristics of TCP transcription factors in A. mongholicus, providing a valuable reference for future investigations into the biological functions of this gene family during growth, development, and abiotic stress responses in this medicinal plant. Full article

Drought is one of the major abiotic stresses limiting soybean production, and its detrimental effects are jointly influenced by stress intensity, duration, and cultivation conditions. To investigate the morphological and physiological regulatory mechanisms by which mepiquat chloride (DPC) alleviates drought stress at the soybean seedling stage, this study used the drought-tolerant soybean cultivar Heinong 44 (H-44) and the drought-sensitive cultivar Heinong 65 (H-65) as experimental materials. Osmotic stress was simulated with 10% PEG-6000 at the V2 stage, and the effects of foliar application of different DPC concentrations (125–500 mg/L) on soybean morphology, biomass allocation, antioxidant systems, and osmotic adjustment capacity were systematically analyzed. The results showed that drought stress significantly inhibited the growth of both soybean cultivars and induced severe oxidative damage. Appropriate DPC concentrations moderately restricted shoot growth to reduce transpiration area while promoting root growth to enhance water acquisition capacity. The optimal DPC concentrations for alleviating drought stress were 200 mg/L for H-44 and 275 mg/L for H-65. Allometric growth analysis indicated that drought disrupted the original root–shoot growth pattern, whereas appropriate DPC concentrations significantly promoted dry matter accumulation in drought-stressed plants and improved root–shoot growth coordination. However, an excessive concentration of DPC (500 mg/L) caused an abnormal deviation in the growth trajectory. In addition, appropriate DPC concentrations synergistically enhanced the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX) in leaves and roots under drought conditions; promoted the accumulation of proline (Pro), soluble sugars (Ss), and soluble proteins (Sp); effectively reduced the contents of malondialdehyde (MDA) and hydrogen peroxide (H₂O₂); and protected cell membrane stability. In conclusion, DPC synergistically enhances drought resistance in soybean by reshaping the root–shoot allometric growth configuration and systematically activating physiological defense networks, providing a theoretical basis for chemically regulated cultivation of soybean under stress conditions. Full article

Cucumber (Cucumis sativus L.) is an economically important vegetable crop worldwide, but its yield and quality improvement are often constrained by drought stress. To investigate the physiological and molecular mechanisms by which exogenous allantoin enhances drought tolerance in cucumber, cucumber seedlings were sprayed with 6 mM allantoin solution once (A1), three times (A3), or five times (A5), while control plants were sprayed with distilled water (CK1, CK3, CK5). Each treatment consisted of three biological replicates. After treatment, drought stress was simulated by irrigating with 20% polyethylene glycol 6000 (PEG-6000) solution. The results showed that the protective effect of exogenous allantoin against drought stress was cumulative. After five applications (A5), the net photosynthetic rate (Pn) and water-use efficiency (WUE) of the plants were significantly higher than those of the corresponding control (CK5) (p < 0.01). The detached leaf water loss rate progressively decreased with an increasing number of allantoin applications, while the total leaf wax content increased approximately 2-fold (p < 0.01). Measurements of wax content in different plant tissues indicated that allantoin mainly induced wax accumulation in aboveground organs (leaf, stem, and fruit epidermis), and this effect was validated in three commercial varieties. Integrated transcriptomic and metabolomic analyses revealed that the cucumber CsCER1 gene (encoding a very-long-chain aldehyde decarbonylase) is a core allantoin-responsive gene. After silencing CsCER1 using virus-induced gene silencing (VIGS), the allantoin-induced wax accumulation and drought tolerance were almost completely lost: the wilting severity and detached leaf water loss rate of the silenced plants were comparable to those of the empty vector control, and no significant increase in wax content was observed. This study reveals a novel mechanism by which exogenous allantoin enhances drought tolerance in cucumber through activating CsCER1-mediated cuticular wax synthesis, providing a theoretical basis for the chemical regulation of drought tolerance in cucurbit crops. Full article

This study used Poacynum hendersonii (Hook. f.) Woods. seedlings as experimental material. A soil drought group (gradual soil drying) and a PEG-simulated drought group (15% PEG-6000 treatment) were established. By combining physiological measurements, metabolomics, and transcriptomics, we investigated the physiological and molecular mechanisms of P. hendersonii in response to drought stress. The results showed that under drought stress, P. hendersonii alleviated oxidative damage by activating the antioxidant enzyme system (catalase, CAT; superoxide dismutase, SOD; peroxidase, POD), and enzyme activities recovered significantly after rehydration. In the osmotic stress group (PEG), hydrogen peroxide (H₂O₂) and malondialdehyde (MDA) contents increased significantly in the later stages, whereas membrane damage was milder in the soil drought group. Metabolomics analysis revealed significant enrichment of starch and sucrose metabolism pathways during early drought, shifting to unsaturated fatty acid biosynthesis and carbon metabolism in later stages. PEG-simulated drought specifically induced the accumulation of arachidonic acid, which may be associated with ferroptosis-like processes, although direct evidence is lacking. Transcriptomics analysis identified 23,623 differentially expressed genes (DEGs), with transcription factor families such as bHLH, MYB, and NAC playing key roles in drought response. Weighted Gene Co-expression Network Analysis (WGCNA) further revealed gene modules significantly correlated with physiological traits, indicating that enhanced respiratory metabolism (glycolysis, tricarboxylic acid (TCA) cycle) is an important strategy for P. hendersonii to adapt to drought. The study also found that while PEG-simulated drought could simulate the physiological effects of soil drought, significant differences existed in molecular pathways, particularly during later stress stages. This research provides a theoretical basis for elucidating the drought resistance mechanisms of P. hendersonii and offers potential targets for crop drought resistance breeding. Full article

This study investigated the vigor and molecular responses of soybean (Glycine max) seedlings belonging to cultivars from various maturity groups under simulated abiotic stress. Seeds and seedlings were subjected to varying concentrations of NaCl (150–300 mM) and PEG-6000 (20–30%), during long-term (12 days) and short-term (72 h) treatments, to evaluate the impact of salinity and drought on seedling viability and gene expression. Molecular analysis via qRT-PCR focused on the transcriptional profiles of the auxin transmembrane influx carrier LAX6, the vacuolar pyrophosphatase H⁺-PP-ase, and the stress protein kinase StrK2. The data indicated a dose-dependent correlation between stress intensity and developmental inhibition; increased concentrations of stress agents generally resulted in delayed germination and reduced survival rates. Certain soybean genotypes exhibited a robust transcriptional response, characterized by a several-fold increase in the expression of all studied genes following stress induction. These findings suggest that soybean abiotic stress responses may be influenced by a complex interaction between stress severity, exposure duration, genotype specificity and the maturity group. Full article

Dry direct seeding (DDS) is a water-saving and high-efficiency rice cultivation system. However, drought stress during DDS severely constrains seedling establishment. This study used the conventional rice variety Zhonghua 11 (ZH11) and the drought-tolerant hybrid Hanyou 73 to investigate the effects of exogenous silicon (Si) on seed germination and seedling growth under drought stress, and to explore the underlying mechanisms of Si-enhanced drought tolerance. Drought stress was imposed using PEG-6000 simulation and pot experiments with different soil relative water contents (60%, 45%, 25%, and 10%). Si treatment significantly alleviated simulated drought inhibition of seed germination, increasing germination percentage and index, improving seedling growth in both varieties. Under simulated DDS conditions, Si significantly improved plant height, biomass, and root development, while maintaining higher net photosynthetic rate, stomatal conductance, intercellular CO₂ concentration, transpiration rate, and chlorophyll content. Meanwhile, Si reduced oxidative damage by promoting proline accumulation, enhancing peroxidase (POD) and catalase (CAT) activities in both leaves and roots, reducing malondialdehyde (MDA) accumulation, and upregulating the expression of key drought-responsive genes (SNAC1, DREB1A, SKIPa, P5CS2). Furthermore, Si upregulated the expression of genes involved in abscisic acid (ABA) (ABA1, ABA2, MHZ5, ABI3) and jasmonic acid (JA) (AOS2, AOS3, JAR1, JAR2, MYC2, COI1a) biosynthesis and signaling. Compared with the wild-type, the ABA signaling mutant abi3 and the JA signaling mutant myc2 exhibited significantly attenuated improvement of plant growth by Si treatment. Collectively, Si enhances antioxidant capacity and osmotic adjustment, maintains photosynthetic function, and is associated with the activation of ABA and JA signaling pathways, which together alleviate the inhibition of rice seedling establishment under DDS-associated drought stress. Our findings provide a theoretical basis for the application of Si fertilizer in DDS rice production. Full article

Drought frequently threatens the yield and quality of Carya cathayensis Sarg. cultivated in mountainous regions. To search for effective drought-resistant regulators is of great significance for alleviating short-term seasonal drought in C. cathayensis during dry seasons, thereby stabilizing its yield and quality. Silicon dioxide nanoparticles (SiO₂ NPs) mitigate abiotic stress in plants. To give insight into the regulatory role of SiO₂ NPs in mitigating drought stress, polyethylene glycol 6000 (PEG-6000) was used to simulate varying degrees of drought conditions, and the growth phenotype, photosynthetic physiological characteristics, antioxidant defense system, and cellular ultrastructure of C. cathayensis leaves were analyzed to evaluate the impacts of foliar-applied exogenous SiO₂ NPs. The results indicated that, compared with severe drought, 200 mg/L SiO₂ NP application to plants under severe drought treatment significantly increased superoxide dismutase and peroxidase activities and chlorophyll and nitrogen contents, while malondialdehyde levels decreased. Furthermore, SiO₂ NP application notably enhanced the net photosynthetic rate, stomatal conductance, and electron transport efficiency. This effectively alleviated both stomatal and non-stomatal limitations, thereby mitigating drought-induced photosynthetic inhibition. Additionally, Transmission electron microscopy revealed that SiO₂ NPs effectively preserved the structural integrity of chloroplasts, mitochondria, and nuclei, reducing drought-induced ultrastructural damage. In conclusion, exogenous SiO₂ NPs enhance drought tolerance in C. cathayensis by synergistically modulating photosynthesis, antioxidant defense, and cellular structural stability. Full article

Henan Province, the foremost wheat-producing region in China, frequently experiences drought stress during the wheat seedling stage. Innovating the evaluation methods for drought resistance at this stage and identifying drought-resistant varieties are crucial for the effective utilization of germplasm. This study utilized 55 wheat varieties that have been bred and promoted in Henan Province in recent years as experimental materials. A 15% PEG-6000 solution was employed to simulate drought stress, and the primary morphological indicators of seedlings, relative chlorophyll content (SPAD), and various chlorophyll fluorescence parameters were assessed. The comprehensive drought resistance scores (D values) for each variety were determined by calculating the drought resistance coefficients for each index, employing principal component analysis, and conducting membership function analysis. Based on the cluster analysis of D values, 55 varieties were categorized into four groups: high drought resistance (10), medium drought resistance (28), low drought resistance (16), and drought-sensitive (1). Seven indicators—SPAD, fresh root weight, seedling height, fresh weight of the aboveground part, Fv/Fm, PItotal, and Mo—were selected as evaluation metrics for the drought resistance of wheat through stepwise regression analysis. The comprehensive evaluation system developed in this study, which is based on morphological and photosynthetic fluorescence characteristics, can swiftly and accurately assess the drought resistance of wheat seedlings. The key indicators identified for highly drought-resistant varieties may serve as valuable references for drought-resistant wheat breeding in Henan Province. Full article

Soybean is a critical oil and protein crop for both food and forage production; however, its growth and development are severely impacted by drought stress. Nevertheless, the molecular regulatory mechanisms underlying drought tolerance in soybean remain poorly understood. In this study, two soybean varieties, Jindou 21 (JD21, drought-tolerant) and Suinong 26 (SN26, drought-sensitive), were used as experimental materials and subjected to 15% PEG6000 to simulate drought stress. Roots and leaves were sampled at 0 h, 6 h, and 12 h after treatment to determine physiological indicators and conduct RNA-seq analysis. The results showed that JD21 exhibited a lower malondialdehyde (MDA) content but higher soluble sugar and proline contents than SN26. A total of 2603 and 3128 osmotic-stress-responsive genes were identified in the roots and leaves of SN26 and JD21, respectively. Additionally, 256 genes in the roots and 215 genes in the leaves showed consistent differential expression between the two varieties across the three treatment time points. KEGG enrichment analysis revealed that the differentially expressed genes were significantly enriched in pathways related to glutathione metabolism, arginine and proline metabolism, glycolysis/gluconeogenesis, and starch and sucrose metabolism. Within these pathways, the functions of GmGST, GmAMD1, GmADH1, GmENO, GmsacA, and GmSUS3 were validated through transgenic hairy root assays, demonstrating that these genes play positive regulatory roles in osmotic stress response. This study provides valuable data for elucidating plant PEG-induced osmotic-stress-response mechanisms and offers theoretical support for drought-resistant soybean breeding. Full article

Drought stress is a major limiting factor for canola production in arid and semi-arid regions, particularly during seed germination, seedling and flowering stages. In this study, we evaluated drought responses of doubled haploid (DH) lines derived from interspecific hybrids of B. napus × B. rapa and their parental cultivars under simulated (PEG-6000) and soil-based drought conditions. Drought stress significantly reduced germination, growth, and physiological performance in all genotypes; however, DH lines consistently exhibited superior tolerance. Under PEG-induced osmotic stress, DH lines maintained higher germination rates, root elongation, and relative water content compared with parental genotypes. During seedling and flowering stages drought, DH lines showed lower accumulation of hydrogen peroxide and malondialdehyde, alongside markedly higher antioxidant enzyme activities (CAT and POD) and improved photosynthetic efficiency (Fv/Fm). Gene expression analysis revealed strong induction of drought-responsive genes, including WRKY28, MYB, LTP, WSP, metallothionein, and protein kinase family genes, particularly in DH lines at prolonged stress exposure. Multivariate analyses (PCA and correlation) confirmed a close association between enhanced antioxidant capacity, transcriptional activation, and drought tolerance traits. Overall, our results demonstrate that homozygous doubled haploid lines derived from distant hybridization between B. napus and B. rapa exhibit enhanced drought tolerance at both early and reproductive stages. These genotypes represent valuable genetic resources for breeding drought-tolerance canola cultivars. Full article