Fine mapping and candidate gene analysis of qGSN5, a novel quantitative trait locus coordinating grain size and grain number in rice

Autor: Mengya Jin, Peng Qin, Zhengyan Xu, Shijie Zhan, Ting Li, Xiaoling Hu, Yuping Wang, Min Yuan, Shigui Li, Peng Gao, Hua Yuan, Wencheng Song, Weilan Chen, Bin Tu, Xiaobo Zhu, Bingtian Ma
Rok vydání: 2021
Předmět:
Zdroj: Theoretical and Applied Genetics. 135:51-64
ISSN: 1432-2242
0040-5752
DOI: 10.1007/s00122-021-03951-7
Popis: KEY MESSAGE: qGSN5, a novel quantitative trait locus coordinating grain size and grain number in rice, was fine-mapped to an 85.60-kb region. GS3 may be a suppressor of qGSN5. Grain size and grain number are two factors that directly determine rice grain yield; however, the underlying genetic mechanisms are complicated and remain largely unclear. In this study, a chromosome segment substitution line (CSSL), CSSL28, which showed increased grain size and decreased grain number per panicle, was identified in a set of CSSLs derived from a cross between 93-11 (recipient) and Nipponbare (donor). Four substitution segments were identified in CSSL28, and the substitution segment located on chromosome 5 was responsible for the phenotypes of CSSL28. Thus, we defined this quantitative trait locus (QTL) as grain size and grain number 5 (qGSN5). Cytological and quantitative PCR analysis showed that qGSN5 regulates the development of the spikelet hull by affecting cell proliferation. Genetic analysis showed that qGSN5 is a semi-dominant locus regulating grain size and grain number. Through map-based cloning and overlapping substitution segment analysis, qGSN5 was finally delimited to an 85.60-kb region. Based on sequence and quantitative PCR analysis, Os05g47510, which encodes a P-type pentatricopeptide repeat protein, is the most likely candidate gene for qGSN5. Pyramiding analysis showed that the effect of qGSN5 was significantly lower in the presence of a functional GS3 gene, indicating that GS3 may be a suppressor of qGSN5. In addition, we found that qGSN5 could improve the grain shape of hybrid rice. Together, our results lay the foundation for cloning a novel QTL coordinating grain size and grain number in rice and provide a good genetic material for long-grain hybrid rice breeding.
Databáze: OpenAIRE
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