Chinese Scientists Find a New Regulatory Module Controlling Grain Size and Yield in Rice

Rice is the most widely consumed staple food for a large part of the world’s human population, especially in Asia. Rice grain size is an important determinant of grain yield, but the molecular mechanisms that control rice grain size remain largely unknown. Thus, identification of grain size regulators will help us understand the relevant molecular mechanisms and will also help improve grain yield by facilitating the breeding of new elite rice varieties.

 

The group of Prof. LI Yunhai from the Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, collaborated with Prof. ZHU Xudong from China National Rice Research Institute and Prof. WANG Junmin from Zhejiang Academy of Agricultural Sciences, identified a new semi-dominant quantitative trait loci (QTL) for gain size and weight (GS2) in rice, which encodes the transcription factor OsGRF4 (GROWTH-REGULATING FACTOR 4) and is regulated by OsmiR396.

 

They found that a 2-bp substitution mutation (TC→AA) in GS2 from the large grain variety (GS2^AA) perturbs OsmiR396-directed regulation of GS2. The GS2^AA allele increased grain size and yield in rice. They further found that the transcription factor GS2 works with the transcription co-activators OsGIF1/2/3 to control grain size and yield.

 

Thus, they discovered a novel molecular mechanism of the OsmiR396-GS2/OsGRF4-OsGIFs regulatory module in grain size and yield control. This regulatory module could be used to engineer large grains size and high grain yield in rice and may help facilitate the molecular breeding of elite rice varieties.

 

This work entitled “Regulation of OsGRF4 by OsmiR396 controls grain size and yield in rice” has been published online in Nature Plants (doi: 10.1038/nplants.2015.203) with DUAN Penggen and ZHANG Baolan from LI Yunhai’s group, NI Shen from ZHU Xudong’s group and WANG Junmin from Zhejiang Acedemy of Agricultural Sciences as the co-first authors.

 

This research is financially supported by National Basic Research Program of China, National Natural Science Foundation of China, Ministry of Agriculture of China and Chinese Academy of Sciences.

 

 

Figure. The OsmiR396-GS2/GRF4-OsGIFs regulatory module controls grain size and yield in rice. (Image by IGDB)

 

AUTHOR CONTACT:

LI Yunhai

Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.

E-mail: yhli@genetics.ac.cn