关键词: 水稻, 乙烯, 矮杆, 图位克隆, 盐胁迫应答

Abstract: Plant height confers important effects on crop yield in rice, which is regulated by many aspects in the growth and development process. Ethylene is one of important factors for regulating plant growth and stress response. In this research, we identified a mutant D814 from the mutants insensitive to ethylene in roots growth. D814 mutants showed the dwarf phenotype, decreased effective tilling numbers and reduced 1000-grain weight. Map-based cloning indicated that D814 located in 1 cM range on chromosome 1, in which there contained six genes contributed to dwarf phenotype in the previous researches. Sequencing analyses demonstrated that OsBRI1（LOC_Os01g52050） has a point mutation at 1 837 bp downstream of ATG, in which the G is changed to T. There were two homologous genes of OsBRI1 in rice, OsBRL1 and OsBRL3, of which the sequences have no mutation in D814 mutants. A reported mutant of OsBRI1, gsor300084, also showed decreased sensitivity to ethylene in root. Due to the function of OsBRI1 was a receptor in brassinosteroid (BR) signal pathway, we found the expressions of BR-response genes were affected in D814, which indicated that D814 was an allele mutant of OsBRI1. Moreover, our analyses showed that D814 affected the expression levels of ethylene signaling-related genes and displayed increased salt tolerance. Thus our research provided a novel research material for exploring the molecular mechanism of ethylene regulating rice growth and stress tolerance, and laid a foundation for investigating the interplay of ethylene and brassinosteroid in growth and development.

Key words: rice, ethylene, dwarf, map-based cloning, salt stress response