State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Institute of Virology and Biotechnology, Zhejiang Academy of Agricultural Sciences, Hangzhou, China.
College of Life Sciences, Zhejiang Sci-Tech University, Hangzhou, China.
Plant Cell Environ. 2021 Oct;44(10):3432-3444. doi: 10.1111/pce.14078. Epub 2021 Aug 19.
Phosphate (Pi) and MYC2-mediated jasmonate (JA) pathway play critical roles in plant growth and development. In particular, crosstalk between JA and Pi starvation signalling has been reported to mediate insect herbivory resistance in dicot plants. However, its roles and mechanism in monocot-bacterial defense systems remain obscure. Here, we report that Pi starvation in rice activates the OsMYC2 signalling and enhances resistance to Xanthomonas oryzae pv. oryzae (Xoo) infection. The direct regulation of OsPHR2 on the OsMYC2 promoter was confirmed by yeast one-hybrid, electrophoretic mobility shift, dual-luciferase and chromatin immunoprecipitation assays. Molecular analyses and infection studies using OsPHR2-Ov1 and phr2 mutants further demonstrated that OsPHR2 enhances antibacterial resistance via transcriptional regulation of OsMYC2 expression, indicating a positive role of OsPHR2-OsMYC2 crosstalk in modulating the OsMYC2 signalling and Xoo infection. Genetic analysis and infection assays using myc2 mutants revealed that Pi starvation-induced OsMYC2 signalling activation and consequent Xoo resistance depends on the regulation of OsMYC2. Together, these results reveal a clear interlink between Pi starvation- and OsMYC2- signalling in monocot plants, and provide new insight into how plants balance growth and defence by integrating nutrient deficiency and phytohormone signalling. We highlighted a molecular link connecting OsMYC2-mediated JA pathway and phosphate starvation signalling in monocot plant. We demonstrated that phosphate starvation promoted OsMYC2 signalling to enhance rice defence to bacterial blight via transcriptional regulation of OsPHR2 on OsMYC2.
磷（Pi）和 MYC2 介导的茉莉酸（JA）途径在植物生长和发育中发挥着关键作用。特别是，已经报道了 JA 和 Pi 饥饿信号之间的串扰在双子叶植物中调节昆虫取食抗性。然而，其在单子叶-细菌防御系统中的作用和机制仍不清楚。在这里，我们报告说，水稻中的 Pi 饥饿会激活 OsMYC2 信号，并增强对稻黄单胞菌 pv 的抗性。oryzae (Xoo) 感染。酵母单杂交、电泳迁移率变动、双荧光素酶和染色质免疫沉淀测定证实了 OsPHR2 对 OsMYC2 启动子的直接调控。分子分析和使用 OsPHR2-Ov1 和 phr2 突变体的感染研究进一步表明，OsPHR2 通过转录调控 OsMYC2 表达增强了抗菌抗性，表明 OsPHR2-OsMYC2 串扰在调节 OsMYC2 信号和 Xoo 感染中发挥了积极作用。使用 myc2 突变体的遗传分析和感染试验表明，Pi 饥饿诱导的 OsMYC2 信号激活和随后的 Xoo 抗性依赖于 OsMYC2 的调节。总之，这些结果揭示了单子叶植物中 Pi 饥饿和 OsMYC2 信号之间的明确联系，并提供了新的见解，即植物如何通过整合营养缺乏和植物激素信号来平衡生长和防御。我们强调了连接单子叶植物中 OsMYC2 介导的 JA 途径和磷酸盐饥饿信号的分子联系。我们证明，磷酸盐饥饿通过转录调控 OsPHR2 对 OsMYC2 的调控，促进 OsMYC2 信号增强水稻对细菌性条斑病的防御。
