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E2 conjugases UBC1 and UBC2 regulate MYB42‐mediated SOS pathway in response to salt stress in Arabidopsis
Author(s) -
Sun Yuhui,
Zhao Jun,
Li Xinyue,
Li Yingzhang
Publication year - 2020
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.16538
Subject(s) - arabidopsis , chromatin immunoprecipitation , histone , ubiquitin , chromatin , microbiology and biotechnology , biology , mutant , histone h2b , phosphorylation , ubiquitin ligase , biochemistry , arabidopsis thaliana , chemistry , gene expression , gene , promoter
Summary Histone H2B monoubiquitination (H2Bub1) is recognized as a crucial eukaryotic regulatory mechanism that controls a range of cellular processes during both development and adaptation to environmental changes. In Arabidopsis , the E2 conjugated enzymes UBIQUITIN CARRIER PROTEINs (UBCs) ‐1 and ‐2 mediate ubiquitination of H2B. Here, we elucidated the functions of UBC1 and ‐2 in salt‐stress responses and revealed their downstream target genes. Real‐time quantitative PCR assays showed that UBC1 and ‐2 positively regulated the salt‐induced expression of MYB42 and Mitogen‐Activated Protein Kinase 4 (MPK4) . Chromatin immunoprecipitation assays revealed that H2Bub1 was enriched weakly on the chromatin of MYB42 and MPK4 in the ubc1,2 mutant. We further determined that UBC1/2‐mediated H2Bub1 enhanced the level of histone H3 tri‐methylated on K4 (H3K4me3) in the chromatin of MYB42 and MPK4 under salt‐stress conditions. MPK4 interacted with and phosphorylated MYB42. The MPK4‐mediated MYB42 phosphorylation enhanced the MYB42 protein stability and transcriptional activity under salt‐stress conditions. We further showed that MYB42 directly bound to the SALT OVERLY SENSITIVE 2 ( SOS2 ) promoter and mediated the rapid induction of its expression after a salt treatment. Our results indicate that UBC1 and ‐2 positively regulate salt‐stress responses by modulating MYB42‐mediated SOS2 expression.