Jasmonates regulate drought resistance by controlling the secondary metabolism in wheat seedlings

Drought severely restricts wheat growth and yield. Clarifying its drought-response regulatory network is critical for the drought-resistant cultivar improvement. In this study, the specific drought-resistant cultivar YH1818 (Yunhan 1818) was chosen for drought simulation to explore the regulatory mechanism in drought stress. Application of exogenous jasmonates could significantly alleviate the damage caused by drought stress in wheat. PEG induced obvious accumulation of proline, soluble sugar, and malondialdehyde (MDA) content, whereas MeJA application markedly reduced both osmotic regulators and MDA content, together with the reduction of O₂⁻ and H2O2, suggesting the alleviated plant damage. Transcriptome analysis presented the high dynamic response to jasmonates and drought conditions in wheat seedlings, especially in root tissue. Besides JA related processes and secondary metabolism were enriched by KEGG analysis, much more pathways were obtained in root tissue, particularly the biosynthesis and metabolism of multiple amino acids. Activation of JA biosynthesis and JA-mediated signaling pathways might act as the key factors for enhancing drought resistance in YH1818. Secondary metabolism including phenylpropanoid biosynthesis and terpenoids biosynthesis controlled by jasmonates might take part in drought response. Moreover, we found diterpenoids biosynthesis showed high relationship with gibberellin (GA) and abscisic acid (ABA) biosynthesis, might contribute to drought resistance in YH1818. WGCNA was applied to construct the co-expression networks and identify hub genes in regulating wheat drought resistance, laying a foundation for dissecting drought-resistance mechanisms and breeding improvement. Exogenous jasmonates significantly alleviated drought damage in YH1818. JA related process might contribute to drought resistance in YH1818 wheat cultivar. Root-focused transcriptomic patterns reveled a strong response to drought stress in root tissues, together with multiple specific pathways were enriched. The core candidate hub genes identified by WGCNA further provide a molecular basis for wheat drought-resistant cultivar improvement.