Abscisic acid and jasmonic acid crosstalk regulates seedling salt tolerance in rice varieties with different salinity tolerances

Abstract The escalating issue of global soil salinization has significantly impacted the growth and productivity of rice ( Oryza sativa L). To investigate the mechanisms underlying rice seedlings’ response to salt stress, transcriptome analysis to examine gene expression changes in salt‐tolerant and salt‐sensitive rice varieties was conducted. Salt‐tolerant landrace rice, Faguodao, and salt‐sensitive cultivar rice, Nipponbare, were used in this study. Both were subjected to 125 mM NaCl treatment at the seedling stage, and transcriptome sequencing was employed to analyze stress‐responsive genes and regulatory networks. Differentially expressed genes in both rice varieties under salt stress were enriched in the abscisic acid (ABA) and jasmonic acid (JA) hormone signaling pathways. Key genes such as OsABIL1 (ABA signaling component) and OsJAZ11 (JA pathway repressor) were identified as pivotal regulators. OsABIL1 promoted ion homeostasis under salt stress, while OsJAZ11 suppression indicated JA signaling inhibition, highlighting ABA's dominance in salt tolerance. Exogenous ABA application significantly alleviated salt stress damage in both genotypes by modulating ion homeostasis, whereas exogenous JA suppressed ABA‐responsive gene expression (e.g., OsPYL4 and OsbZIP23), indicating an antagonistic interaction between the two hormones. Under salt stress, exogenous ABA effectively alleviates the damage in both salt‐tolerant and salt‐sensitive rice. In contrast, exogenous JA suppressed the expression of ABA‐related genes, diminishing ABA's alleviating effects and indicating an antagonistic interaction between ABA and JA in regulating rice salt tolerance. This study provides valuable insights into the intricate regulatory network of ABA and JA regulating salt tolerance in rice seedlings.