Premium
Wide Grain 7 increases grain width by enhancing H3K4me3 enrichment in the OsMADS1 promoter in rice ( Oryza sativa L.)
Author(s) -
Huang Yong,
Bai Xufeng,
Cheng Niannian,
Xiao Jinghua,
Li Xianghua,
Xing Yongzhong
Publication year - 2020
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/tpj.14646
Subject(s) - h3k4me3 , mutant , promoter , oryza sativa , biology , gene , microbiology and biotechnology , grain size , activator (genetics) , gene expression , genetics , materials science , metallurgy
Summary Grain size is a major determinant of grain weight, a key component of grain yield of rice. Here, we identified the grain size gene WIDE GRAIN 7 ( WG7 ) from a T‐DNA insertion mutant. The grain size of WG7 knockout mutants and WG7 overexpression lines indicated that WG7 is a positive regulator of grain size. WG7 encodes a cysteine‐tryptophan (CW) domain‐containing transcriptional activator. EMSAs and ChIP‐qPCR assay confirmed that WG7 directly bound to the promoter of OsMADS1 , a grain size gene, and thereby significantly activated its expression. Point mutations showed that the cis ‐element CATTTC motif in the promoter was the binding site of WG7. Compared with the wild‐type, deletion mutants of the cis ‐element motif exhibited lower expression of OsMADS1 and produced narrower grains, implicating the requirement of this motif for WG7 function. ChIP‐qPCR assays showed that WG7 enhanced histone H3K4me3 enrichment in the promoter of OsMADS1 . WG7 underwent directional selection due to the poor fertility of the non‐functional mutant. These findings demonstrated that WG7 upregulated OsMADS1 expression by directly binding to its promoter, enhanced histone H3K4me3 enrichment in the promoter and ultimately increased grain width. This study will enrich the knowledge concerning the regulatory network of grain size formation in rice.