OsMAPK6 phosphorylates a zinc finger protein OsLIC to promote downstream OsWRKY30 for rice resistance to bacterial blight and leaf streak

Abstract

Rice OsLIC encoding a CCCH zinc finger transcription factor plays an important role in immunity. However, the immune signaling pathways that OsLIC‐involved and the underlying mechanisms that OsLIC‐conferred resistance against pathogens are largely unclear. Here, we show that OsLIC, as a substrate for OsMAPK6, negatively regulates resistance to Xanthomonas oryzae pv. oryzae (Xoo) and X. oryzae pv. oryzicola (Xoc) by directly suppressing OsWRKY30 transcription. Biochemical assays showed that OsLIC bound to OsWRKY30 promoter and suppressed its transcription. Genetic assays confirmed that the osilc knockout mutants and OsWRKY30‐overexpressing plants exhibited enhanced resistance to Xoo and Xoc, knocking out OsWRKY30 in the oslic mutants attenuated the resistance against bacterial pathogens. OsMAPK6 physically interacted with and phosphorylated OsLIC leading to decreased OsLIC DNA‐binding activity, therefore, overexpression of OsLIC partially suppressed OsMAPK6‐mediated rice resistance. In addition, both OsMAPK6‐phosphorylated activation of OsLIC and phosphorylation‐mimic OsLIC5D had reduced DNA‐binding activity towards OsWRKY30 promoter, thereby promoting OsWRKY30 transcription. Collectively, these results reveal that OsMAPK6‐mediated phosphorylation of OsLIC positively regulates rice resistance to Xoo and Xoc by modulating OsWRKY30 transcription, suggesting that OsMAPK6‐OsLIC‐OsWRKY30 module is an immune signaling pathway in response to the bacterial pathogens.

Mechanism Analysis of OsZF8-Mediated Regulation of Rice Resistance to Sheath Blight

“…MdBBX7/MdCOL9 can be directly ubiquitinated and degraded by E3 ubiquitin ligase MIEL1, which reduces apple tolerance to drought stress [ 37 ]. CCCH-type zinc finger protein OsLIC, as a substrate of OsMAPK6, can be activated by phosphorylation of OsMAPK6 to regulate rice resistance to Xoo and Xoc [ 38 ]. AtZAT6 positively modulates expression levels of stress-related genes by directly binding to the promoter region of pathogen-related genes like PR1 and PR5 [ 39 ].…”

A B‐box transcription factor OsBBX17 regulates saline‐alkaline tolerance through the MAPK cascade pathway in rice

“…In rice, phosphorylation of OsWRKY31 by OsMPK3, OsMPK4, and OsMPK6 enhances resistance to Magnaporthe oryzae (S. Wang et al ., 2023). OsMAPK6 phosphorylates a zinc finger protein OsLIC to promote downstream OsWRKY30 resistance to bacterial blight and leaf streak (L. H. Wang et al ., 2022). BBXs through post‐translational modifications to mediate plant stress responses have also been reported.…”

Hypothetical protein FoDbp40 influences the growth and virulence of Fusarium oxysporum by regulating the expression of isocitrate lyase

“…Homologs in other fungi such as Aspergillus fumigatus and Torrubiella hemipterigena are annotated as CCCH zinc finger DNA binding proteins. Although CCCH zinc finger proteins were known as RNA-binding proteins ( Fu and Blackshear, 2017 ), Recent studies showed that CCCH zinc finger proteins also bind to DNA and modulate transcription ( Zou et al, 2018 ; Wang et al, 2022 ). Therefore, we speculate that FoDbp40 may have the ability to bind target DNA and function in transcriptional regulation.…”

“…CCCH zinc finger proteins are known as RNA-binding proteins and associated with post-transcriptional regulation of mRNA ( Fu and Blackshear, 2017 ). In addition to its role in RNA metabolism, recent studies demonstrated that CCCH zinc finger proteins also modulate transcription ( Zou et al, 2018 ; Wang et al, 2022 ). A RNA-binding CCCH zinc finger protein Zc3h10 was also proved to activate UCP1 promoter by binding to a distal upstream region ( Yi et al, 2019 ).…”