Natural variation in WHITE-CORE RATE 1 regulates redox homeostasis in rice endosperm to affect grain quality

第一作者：Bian Wu

第一单位：华中农业大学

第一通讯：Yuqing He

 Abstarct 

背景回顾：Grain chalkiness reduces the quality of rice (Oryza sativa) and is a highly undesirable trait for breeding and marketing. 

籽粒垩白会降低稻米的品质，是育种和经销时极不理想的性状。

提出问题：However, the underlying molecular cause of chalkiness remains largely unknown. 

然而，稻米垩白的潜在分子机制尚不清楚。

主要发现：Here, we cloned the F-box gene WCR1 (WHITE-CORE RATE 1), which negatively regulates grain chalkiness and improves grain quality in rice. 

本文中，作者克隆到了一个F-box基因WCR1，该基因对稻米垩白有负调节作用，并能够改善稻米品质。

结果1-两个等位基因：A functional A/G variation in the promoter region of WCR1 generates the alleles WCR1^A and WCR1^G, which originated from tropical japonica (TrJ) and wild rice O. rufipogon, respectively. 

WCR1启动子区域的功能性A/G变异产生了两个等位基因，即WCR1A和WCR1G，分别来源于热带粳稻（TrJ）和野生稻（O. rufipogon）。

结果2-WCR1上游：OsDOF17 is a transcriptional activator that binds to the AAAAG cis-element in the WCR1A promoter. 

OsDOF17是一种转录激活因子，能够结合到WCR1A启动子的AAAAG顺式元件。

结果3-WCR1下游：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. 

WCR1能够正向调控金属硫蛋白编码基因MT2b的转录，并与MT2b相互作用以抑制其被26S蛋白酶体介导的降解，从而降低了水稻胚乳中的活性氧物质和延迟了细胞的程序性死亡。转而，这会导致稻米的白垩程度降低。

结论：Our findings uncover a molecular mechanism underlying rice chalkiness and identify the promising natural variant WCR1A, with application potential for rice breeding.

本文的研究结果揭示了水稻垩白的分子机制，并鉴定了一个有希望被用来改善稻米品质自然变体WCR1A，具有应用于水稻育种的巨大潜力。

** 何予卿 **

doi: https://doi.org/10.1093/plcell/koac057

Journal: The Plant Cell​

Published date: February 16, 2022