Open AccessMutation of RGG 2 , which encodes a type B heterotrimeric G protein γ subunit, increases grain size and yield production in rice
Author(s) -
Miao Jun,
Yang Zefeng,
Zhang Dongping,
Wang Yuzhu,
Xu Mengbin,
Zhou Lihui,
Wang Jun,
Wu Shujun,
Yao Youli,
Du Xi,
Gu Fangfei,
Gong Zhiyun,
Gu Minghong,
Liang Guohua,
Zhou Yong
Publication year - 2019
Publication title -
plant biotechnology journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.525
H-Index - 115
eISSN - 1467-7652
pISSN - 1467-7644
DOI - 10.1111/pbi.13005
Subject(s) - heterotrimeric g protein , biology , mutant , crispr , protein subunit , oryza sativa , plant stem , gene , yield (engineering) , microbiology and biotechnology , botany , genetics , g protein , signal transduction , materials science , metallurgy
Summary Heterotrimeric G proteins, which consist of G α , G β and G γ subunits, function as molecular switches that regulate a wide range of developmental processes in plants. In this study, we characterised the function of rice RGG 2 , which encodes a type B G γ subunit, in regulating grain size and yield production. The expression levels of RGG 2 were significantly higher than those of other rice G γ ‐encoding genes in all tissues tested, suggesting that RGG 2 plays essential roles in rice growth and development. By regulating cell expansion, overexpression of RGG2 in Nipponbare ( NIP ) led to reduced plant height and decreased grain size. By contrast, two mutants generated by the clustered, regularly interspaced, short palindromic repeat ( CRISPR )/CRISPR‐associated protein 9 (Cas9) system in the Zhenshan 97 ( ZS 97) background, zrgg2‐1 and zrgg2‐2 , exhibited enhanced growth, including elongated internodes, increased 1000‐grain weight and plant biomass and enhanced grain yield per plant (+11.8% and 16.0%, respectively). These results demonstrate that RGG 2 acts as a negative regulator of plant growth and organ size in rice. By measuring the length of the second leaf sheath after gibberellin ( GA 3 ) treatment and the GA ‐induced α‐amylase activity of seeds, we found that RGG 2 is also involved in GA signalling. In summary, we propose that RGG 2 may regulate grain and organ size via the GA pathway and that manipulation of RGG 2 may provide a novel strategy for rice grain yield enhancement.