CLUSTERED PRIMARY BRANCH 1, a new allele of DWARF11, controls panicle architecture and seed size in rice |
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Authors: | Yongzhen Wu Yongcai Fu Shuangshuang Zhao Ping Gu Zuofeng Zhu Chuanqing Sun Lubin Tan |
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Affiliation: | 1. Department of Plant Genetics and Breeding, National Center for Evaluation of Agricultural Wild Plants (Rice), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, China;2. State Key Laboratory of Plant Physiology and Biochemistry, China Agricultural University, Beijing, China |
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Abstract: | Panicle architecture and seed size are important agronomic traits that directly determine grain yield in rice (Oryza sativa L.). Although a number of key genes controlling panicle architecture and seed size have been cloned and characterized in recent years, their genetic and molecular mechanisms remain unclear. In this study, we identified a mutant that produced panicles with fascicled primary branching and reduced seeds in size. We isolated the underlying CLUSTERED PRIMARY BRANCH 1 (CPB1) gene, a new allele of DWARF11 (D11) encoding a cytochrome P450 protein involved in brassinosteroid (BR) biosynthesis pathway. Genetic transformation experiments confirmed that a His360Leu amino acid substitution residing in the highly conserved region of CPB1/D11 was responsible for the panicle architecture and seed size changes in the cpb1 mutants. Overexpression of CPB1/D11 under the background of cpb1 mutant not only rescued normal panicle architecture and plant height, but also had a larger leaf angle and seed size than the controls. Furthermore, the CPB1/D11 transgenic plants driven by panicle‐specific promoters can enlarge seed size and enhance grain yield without affecting other favourable agronomic traits. These results demonstrated that the specific mutation in CPB1/D11 influenced development of panicle architecture and seed size, and manipulation of CPB1/D11 expression using the panicle‐specific promoter could be used to increase seed size, leading to grain yield improvement in rice. |
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Keywords: |
Oryza sativa
brassinosteroid panicle architecture seed size transgenic plants |
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