OsPHR2 modulates phosphate starvation-induced jasmonic acid response and resistance to Xanthomonas oryzae pv. oryzae

Abstract

Phosphate (Pi) and jasmonic acid (JA) play critical roles in plant growth and development. In particular, crosstalk between JA and Pi starvation signaling 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 JA signaling 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 JA response and antibacterial resistance via transcriptional regulation of OsMYC2 expression, indicating a positive role of OsPHR2-OsMYC2 crosstalk in modulating the JA response and Xoo infection. Genetic analysis and infection assays using myc2 mutants revealed that Pi starvation-induced JA signaling activation and consequent Xoo resistance depends on the regulation of OsMYC2. Together, these results reveal a clear interlink between Pi starvation signaling and the JA signaling in monocot plants, and provide new insight into how plants balance growth and defense by integrating nutrient deficiency and phytohormone signaling.

OsGLP3‐7 positively regulates rice immune response by activating hydrogen peroxide, jasmonic acid, and phytoalexin metabolic pathways

“…Moreover, osmyc2 plants (Shi et al, 2021 ), which are defective in JA signalling, were used for blast and bacterial blight resistance analysis. As expected, the osmyc2 plants exhibited decreased resistance to leaf blast and bacterial blight compared to the wild‐type Nipponbare plants (Figure S11 ), consistent with the observations reported by two recent studies (Kong et al, 2021 ; Qiu et al, 2022 ). These results together indicate that the JA signalling pathway plays an important role in rice disease resistance conferred by OsGLP3‐7 .…”

The Mutation of Rice MEDIATOR25, OsMED25, Induces Rice Bacterial Blight Resistance through Altering Jasmonate- and Auxin-Signaling

“…RERJ1 interacts with OsMYC2 and positively regulates production of linalool by upregulating linalool synthase [19]. OsMYC2 is also activated under phosphate starvation conditions, resulting in the induction of resistance to Xoo in rice [22]. The OsMYC2 activity is suppressed by a complex that consists of rice JASMONATE ZIM (JAZ)-domain proteins (OsJAZs) and rice NOVEL INTERACTOR OF JAZ1 (OsNINJA1) [17,23].…”