Hu Yong, Zhou Xin, Zhang Bo, Li Shuangle, Fan Xiaowei, Zhao Hu, Zhang Jia, Liu Haiyang, He Qin, Li Qiuping, Ayaad Mohammed, You Aiqing, Xing Yongzhong
Hubei Key Laboratory of Food Crop Germplasm and Genetic Improvement, Food Crops Research Institute, Hubei Academy of Agricultural Sciences, Wuhan, 430064, China.
National Key Laboratory of Crop Genetic Improvement and National Center of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan, 430070, China.
Rice (N Y). 2021 Feb 25;14(1):20. doi: 10.1186/s12284-021-00464-1.
Heading date is an important agronomic trait of rice (Oryza sativa L.) and is regulated by numerous genes, some of which exhibit functional divergence in a genetic background-dependent manner. Here, we identified a late heading date 7 (lhd7) mutant that flowered later than wild-type Zhonghua 11 (ZH11) under natural long-day (NLD) conditions. Map-based cloning facilitated by the MutMap strategy revealed that LHD7 was on the same locus as OsPRR37 but exhibited a novel function as a promoter of heading date. A single-nucleotide mutation of G-to-A in the coding region caused a substitution of aspartic acid for glycine at site 159 within the pseudo-receiver (PR) domain of OsPRR37. Transcriptional analysis revealed that OsPRR37 suppressed Ghd7 expression in both ZH11 background under NLD conditions and the Zhenshan 97 background under natural short-day conditions. Consistently, the expression of Ehd1, Hd3a and RFT1 was enhanced by OsPRR37 in the ZH11 background. Genetic analysis indicated that the promotion of heading date and reduction in grain yield by OsPRR37 were partially dependent on Ghd7. Further investigation showed that the alternative function of OsPRR37 required an intact Ghd7-related regulatory pathway involving not only its upstream regulators OsGI and PhyB but also its interacting partner Hd1. Our study revealed the distinct role of OsPRR37 in the ZH11 background, which provides a more comprehensive understanding of OsPRR37 function and enriches the theoretical bases for improvement of rice heading date in the future.
抽穗期是水稻（Oryza sativa L.）重要的农艺性状，受众多基因调控，其中一些基因在遗传背景依赖的方式下表现出功能差异。在此，我们鉴定了一个晚抽穗期7（lhd7）突变体，在自然长日照（NLD）条件下，其抽穗时间比野生型中花11（ZH11）晚。通过MutMap策略进行的图位克隆表明，LHD7与OsPRR37位于同一基因座，但作为抽穗期的促进因子发挥新功能。编码区G到A的单核苷酸突变导致OsPRR37伪受体（PR）结构域第159位的甘氨酸被天冬氨酸取代。转录分析表明，在NLD条件下的ZH11背景以及自然短日照条件下的珍汕97背景中，OsPRR37均抑制Ghd7表达。同样，在ZH11背景中，OsPRR37增强了Ehd1、Hd3a和RFT1的表达。遗传分析表明，OsPRR37对抽穗期的促进作用和对产量的降低作用部分依赖于Ghd7。进一步研究表明，OsPRR37的替代功能需要完整的Ghd7相关调控途径，该途径不仅涉及其上游调控因子OsGI和PhyB，还涉及其相互作用伙伴Hd1。我们的研究揭示了OsPRR37在ZH11背景中的独特作用，这为更全面理解OsPRR37功能提供了依据，并丰富了未来改良水稻抽穗期的理论基础。
