Jasmonate ZIM-domain protein 2 orchestrates ABA/JA signaling and flavonoid biosynthesis to suppress cold tolerance in grapevine.

Cold stress tolerance in pepper: role of transcription factors in molecular signaling and adaptive responses

By elucidating the molecular mechanisms underlying cold stress responses, it offers key perspectives for the breeding of climate-tolerant pepper varieties to ensure sustainable agricultural production.

OsMYBAS1 Coordinates ABA/JA Signaling and ROS Homeostasis for Seedling Cold Tolerance of Rice (Oryza sativa L.).

Seedling cold stress is a major abiotic constraint to rice production, and mining elite cold-tolerant genes from wild rice represents a pivotal strategy to enhance cold tolerance in cultivated rice (Oryza sativa L.). Dongxiang wild rice (DXWR, Oryza rufipogon Griff.) is a valuable genetic resource with robust cold tolerance. However, the underlying molecular regulatory mechanisms remain poorly characterized, and the identification of its elite cold-tolerant genes is still limited. In this study, by integrating high-density gene chip, comparative transcriptomic and functional correlation analyses, we identified OsMYBAS1, an R2R3-MYB transcription factor, as a key regulator conferring cold tolerance of DXWR. The Osmybas1 mutants exhibited drastically reduced survival rate under cold stress, accompanied by excessive reactive oxygen species (ROS) accumulation and significant decreases in antioxidant enzyme activity. Comparative transcriptome analysis of the mutants identified 545 cold-induced differentially expressed genes. Functional enrichment analysis indicated that pathways involved in hormone metabolism and signaling were among the most significantly enriched categories, highlighting their key roles in the cold response. Further detection revealed that endogenous abscisic acid (ABA) and jasmonic acid (JA) levels were markedly down-regulated in Osmybas1 mutants after cold treatment, while exogenous ABA or methyl jasmonate (MeJA) application rescued the cold-sensitive phenotype and reversed the abnormal expression of cold-responsive genes. This study suggested that OsMYBAS1 positively regulated seedling cold tolerance by mediating the coordinated modulation of ABA/JA signaling and ROS homeostasis. These findings elucidated an important molecular mechanism underlying DXWR cold tolerance and provided a novel gene target and theoretical foundation for cold-tolerant rice molecular breeding.

Functional Divergence of DREB Transcription Factors in Crop Abiotic Stress Tolerance: A Mini-Review

Regulation Mechanism of JA Signaling on the Expansin Gene SlEXPA8 Affecting Sugar Metabolism in Tomato

Carbohydrates are crucial for plant growth and serve as fundamental energy sources, regulated by multiple factors. In tomato, development is closely linked to hormone‐mediated sugar metabolism. Although jasmonic acid (JA) is known to function in signaling and growth regulation, its specific role in sugar metabolism remains unclear. This study demonstrated that JA signaling negatively regulates tomato seedling growth. Exogenous application of the JA activator MeJA suppressed growth, whereas the JA inhibitor DIECA and the JA synthesis mutant spr2 promoted it. Further analysis revealed that JA impaired growth by inhibiting photosynthesis—reducing photosynthetic pigment content and efficiency. MeJA treatment increased fructose and glucose levels but decreased sucrose and starch. These changes resulted from downregulated sucrose synthase (SlSS, SlSPS) activity and expression, alongside upregulated acid invertase (SlAI, SlNI) activity and SlTIV1 expression. Thus, JA restricted tomato seedling growth by suppressing photosynthesis and promoting soluble sugar accumulation. Transcriptome analysis identified SlEXPA8, a JA‐responsive expansin gene. JA signaling downregulated SlEXPA8 expression; silencing SlEXPA8 impaired photosynthesis, reduced activities of sucrose‐metabolizing enzymes, and lowered sucrose and starch levels, inhibiting seedling growth. Overexpression of SlEXPA8, however, enhanced growth. EMSA, ChIP, GUS, and LUC assays confirmed that SlMYC2 directly bound the SlEXPA8 promoter and regulated its transcription. These findings uncovered a mechanism by which JA signaling modulated sugar metabolism via expansin proteins, offering insights for targeted genetic improvement of tomato seedling vigor.

Flavonoid Biosynthesis Mediated by GmF3Hs Contributes to Drought Tolerance in Soybean.

Flavonoids are central to abiotic stress responses, yet the specific signaling roles and evolutionary dynamics of flavonoid biosynthetic intermediates in crop drought adaptation remain elusive. Here, we demonstrate that dihydrokaempferol (DHK) and dihydroquercetin (DHQ), specific intermediate products of the soybean flavanone 3-hydroxylases GmF3H1/2, function as potent signaling molecules that mitigate drought stress. Exogenous DHK/DHQ promoted ABA-dependent stomatal closure and enhanced drought tolerance across diverse dicot species including soybean and tobacco, highlighting a broadly conserved stress-mitigating signaling mechanism. CRISPR/Cas9-generated gmf3hs double mutants exhibited severe drought hypersensitivity due to compromised redox homeostasis and defective stomatal regulation, which could be specifically functionally rescued by DHK/DHQ application. Furthermore, the loss of GmF3H triggered a distinct reproductive trade-off under stress, leading to increased pod initiation but severe filling defects. Multi-omics network analysis revealed extensive rewiring of broader stress-responsive pathways and identified upstream transcription factors, among which GmPHL11 directly binds to and activates the GmF3H1 promoter, and overexpression of GmPHL11 promoted DHK accumulation and enhanced drought stress tolerance in soybean hairy roots. Finally, population genomic analyses demonstrated that the GmF3H1H1 haplotype, which confers superior enzymatic activity and robust root growth under drought stress, might underwent positive selection during soybean domestication. Collectively, our findings redefine the role of GmF3H-derived specific intermediates as potent signaling molecules, providing comprehensive mechanistic and evolutionary insights into flavonoid-mediated drought resilience, developmental trade-offs, and molecular breeding in crops.

GmSNAT1 enhances cold tolerance in soybean by promoting melatonin biosynthesis and interacting with GmPSYR1.

It is demonstrated that cold adaptation in soybeans is synergistically enhanced by GmSNAT1 via a multidimensional axis encompassing melatonin synthesis, signal transduction, and physiological protection, thereby providing a novel molecular target for breeding cold-tolerant crops.