OsWRKY39 regulates phenylpropanoid metabolic reprogramming to orchestrate rice immunity against Magnaporthe oryzae

Magnaporthe oryzae threatens global rice production, but master regulators coordinating immunity, metabolism, and growth remain elusive. Here, we identify OsWRKY39 as a central hub integrating blast resistance, phenylpropanoid metabolism, hormone homeostasis, and growth-defense trade-offs, distinct from OsWRKY45 (only activates diterpenoid phytoalexin biosynthesis). OsWRKY39 overexpression (OE) enhances blast resistance, while knockout (ko) lines are susceptible. DAP-seq/EMSA show OsWRKY39 directly targets W-box in promoters of OsPAL7, OsCKX2, OsJAZ9, and OsWRKY70. DLR assays reveal OsWRKY39 represses OsCKX2 and activates OsARF16 promoters. Transcriptomic/metabolomic analyses show OE plants reprogram phenylpropanoid metabolism to accumulate antimicrobial metabolites upon infection, whereas ko lines lose this control. OsWRKY39 elevates cytokinins (e.g., DHZR) to boost ATP/NADPH, suppresses excessive JA via OsJAZ9, and alleviates growth-resistance tradeoff via cytokinin-auxin crosstalk. BiFC confirms JA attenuates OsJAZ9-OsMYC2 interaction. Co-IP/phosphorylation assays show OsWRKY39 interacts with and is phosphorylated by OsMPK13. Our findings establish OsWRKY39 as a master regulator orchestrating rice immunity-metabolism-growth networks, minimizing growth costs and providing targets for high-yield, blast-resistant cereals.