Phenotypic analysis and molecular characterization of an allelic mutant of the D61 gene in rice
Yanan Gao,
Guangquan Wang,
Shoujiang Yuan,
Yanling Qin,
Jinfeng Zhao,
Yanpei Zhang,
Wenhui Zhang,
Xueyong Li
Affiliations
Yanan Gao
College of Life Sciences, Liaocheng University, Liaocheng, Shandong 252059, China; National Key Facility for Crop Gene Resource and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing 100081, China
Guangquan Wang
College of Life Sciences, Liaocheng University, Liaocheng, Shandong 252059, China
Shoujiang Yuan
Shandong Rice Research Institute, Jinan 250100, China
Yanling Qin
National Key Facility for Crop Gene Resource and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing 100081, China
Jinfeng Zhao
National Key Facility for Crop Gene Resource and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing 100081, China
Yanpei Zhang
National Key Facility for Crop Gene Resource and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing 100081, China;College of Agriculture, Shandong Agricultural University, Tai'an, Shandong 271018, China
Wenhui Zhang
College of Life Sciences, Liaocheng University, Liaocheng, Shandong 252059, China
Xueyong Li
National Key Facility for Crop Gene Resource and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing 100081, China
Brassinosteroids (BRs) are a class of plant-specific steroidal hormones that play important roles in multiple biological processes. In this paper, a classic rice mutant gsor300084, showing erect leaves and semi-dwarf stature, was characterized. Morphological analysis in darkness showed that the mesocotyl of the gsor300084 mutant did not elongate when grown in darkness. Coleoptile elongation and root growth were less affected by the exogenous application of brassinolide (BL), the most active form of BR, in gsor300084 than in the wild-type rice variety Matsumae. Lamina joint bending analysis also showed that gsor300084 was less sensitive to exogenous BL than Matsumae. These results suggested that the gsor300084 mutant is defective in BR sensitivity. Map-based cloning indicated that gsor300084 is a novel allelic mutant of the DWARF61 (D61) gene, which encodes the putative BR receptor OsBRI1. A single-base mutation appears in the LRR domain of OsBRI1, changing the 444th amino acid from tryptophan (W) to arginine (R). Subcellular localization analysis suggested that both the wild-type and mutant OsBRI1 protein are localized at the cytoplasmic membrane. Structure modeling revealed that the W444R substitution may affect the perception of BRs by the LRR domain.
