Recently, Prof. Zhang Jian and Prof. Huang Shiwen’s teams from China National Rice Research Institute (CNRRI), CAAS published their research work entitled “SAPK10-mediated phosphorylation on WRKY72 releases its suppression on jasmonic acid biosynthesis and bacterial blight resistance” on iScience, a new interdisciplinary journal from Cell Press. This work revealed a novel mechanism of rice defense against bacterial blight through a SAPK10-WRKY72-AOS1 module.

Bacterial blight caused by the infection of Xanthomonas oryzae pv. Oryzae (Xoo) is a devastating disease that severely challenges the rice yield. WRKY transcription factor family is extensively involved in rice defense to biotic invasion, but the defense mechanisms vary from one another. This study revealed that WRKY72, a member of the WRKY family directly binds to the W-box in the promoter of JA biosynthesis gene AOS1, and represses its transcription via inducing DNA hypermethylation on the target site, which finally led to lower endogenous JA level and higher Xoo susceptibility. Further studies demonstrated that ABA-inducible SnRK2 type kinase SAPK10 phosphorylates WRKY72 at Thr 129. The SAPK10-mediated phosphorylation impairs the DNA binding ability of WRKY72, and releases its suppression on AOS1 and JA biosynthesis. The work highlighted a module of how pathogen stimuli lead to plant susceptibility, as well as a potential pathway for ABA-JA interplay with post-translational modification and epigenetic regulation mechanism involved.

This study was supported by National Natural Science Foundation of China (grant number: 31601288, 31701395 and 31871229), Key R&D Project of Zhejiang Province (2019C02018), Agricultural Sciences and Technologies Innovation Program of Chinese Academy of Agricultural Sciences to Rice Reproductive Developmental Biology Group and Chinese High-yielding Rice Transgenic Program (Grant No. 2016ZX08001004-001). More details are available on below link: https://onlinelibrary.wiley.com/doi/pdf/10.1111/pbi.13048.