On February 16, 2022, Prof. He Yuqing, together with his team, published a paper online in The Plant Cell, titled “Natural variation in WHITE-CORE RATE 1 regulates redox homeostasis in rice endosperm to affect grain quality”. This paper reveals the natural variation in WCR1 and the molecular mechanism of how redox homeostasis in rice endosperm affects chalkiness formation.
A: WCR1 map-based cloning; B: Near-isogenic plant type and grain chalkiness phenotype; C: Regulatory model of WCR1 involved in chalkiness formation.
Grain chalkiness reduces the quality of rice ( Oryza sativa ) and is a highly undesirable trait for breeding and marketing. However, the underlying molecular cause of chalkiness remains largely unknown. Here, the F-box gene WCR1 ( WHITE-CORE RATE 1 ) was cloned, which negatively regulates grain chalkiness and improves grain quality in rice. A functional A/G variation in the promoter region of WCR1 generates the alleles WCR1A and WCR1G , which originated from tropical japonica ( TrJ ) and wild rice O. rufipogon, respectively. OsDOF17 is a transcriptional activator that binds to the AAAAG cis-element in the WCR1A promoter. WCR1 positively affects the transcription of the metallothionein gene MT2b and interacts with MT2b to inhibit its 26S proteasome-mediated degradation, leading to decreased reactive oxygen species production and delayed programmed cell death in rice endosperm. This, in turn, leads to reduced chalkiness. The findings uncover a molecular mechanism underlying rice chalkiness and identify the promising natural variant WCR1A , with application potential for rice breeding.
WCR1 is another important discovery of the team after the cloning of Chalk5 (Li et al, Nature Genetics, 2014). Wu Bian, a PhD student at HZAU’s National Key Laboratory of Crop Genetic Improvement, is the first author of this paper, and Prof. He Yuqing is the corresponding author. In addition, Prof. Yao Jialing and Prof. Zhou Zhuqing participated in the research. This research was co-funded by the National Key Research and Development Program and the National Natural Science Foundation of China.
Source: http://news.hzau.edu.cn/2022/0220/62628.shtml
Translated by: Duan Jun, Tang Fangyi, Yang Jian, Bi Cheng
Supervised by: Zhang Juan
