WIDE AND THICK GRAIN 1, which encodes an otubain‐like protease with deubiquitination activity, influences grain size and shape in rice. (20th July 2017)

• Record Type: Journal Article
• Authors: Huang, Ke; Wang, Dekai; Duan, Penggen; Zhang, Baolan; Xu, Ran; Li, Na; Li, Yunhai
• Is Part Of: Plant journal. Volume 91:Number 5(2017)
• Page Start: 849
• Page End: 860
• Publication Date: 2017-07-20
• Subjects: rice -- WTG1 -- grain size and shape -- grain weight -- cell expansion; Plant molecular biology -- Periodicals; Plant cells and tissues -- Periodicals; Botany -- Periodicals; 580
• DOI: 10.1111/tpj.13613
• Languages: English
• ISSNs: 0960-7412

Abstract

Summary: Grain size and shape are two crucial traits that influence grain yield and grain appearance in rice. Although several factors that affect grain size have been described in rice, the molecular mechanisms underlying the determination of grain size and shape are still elusive. In this study we report that WIDE AND THICK GRAIN 1 (WTG1) functions as an important factor determining grain size and shape in rice. The wtg1‐1 mutant exhibits wide, thick, short and heavy grains and also shows an increased number of grains per panicle. WTG1 determines grain size and shape mainly by influencing cell expansion. WTG1 encodes an otubain‐like protease, which shares similarity with human OTUB1. Biochemical analyses indicate that WTG1 is a functional deubiquitinating enzyme, and the mutant protein (wtg1‐1) loses this deubiquitinating activity. WTG1 is expressed in developing grains and panicles, and the GFP–WTG1 fusion protein is present in the nucleus and cytoplasm. Overexpression of WTG1 results in narrow, thin, long grains due to narrow and long cells, further supporting the role of WTG1 in determining grain size and shape. Thus, our findings identify the otubain‐like protease WTG1 to be an important factor that determines grain size and shape, suggesting that WTG1 has the potential to improve grain size and shape in rice. Significance Statement: How seed size is determined is a fundamental question in plant developmental biology. However, the mechanisms underlying seed size and shape determination are largely elusive. Here we identify the otubain‐like protease WTG1 as an important factor that determines grain size and shape in rice, suggesting that it has the potential for improving seed size and shape in key crops.