The divergence of brassinosteroid sensitivity between rice subspecies involves natural variation conferring altered internal auto‐binding of OsBSK2. Issue 8 (28th July 2022)

• Record Type: Journal Article
• Authors: Yin, Wenchao; Li, Lulu; Yu, Zhikun; Zhang, Fan; Liu, Dapu; Wu, Hongkai; Niu, Mei; Meng, Wenjing; Zhang, Xiaoxing; Dong, Nana; Yang, Yanzhao; Liu, Jihong; Liu, Yongqiang; Zhang, Guoxia; Xu, Jianlong; Wang, Shimei; Chu, Chengcai; Qian, Qian; Tong, Hongning
• Is Part Of: Journal of integrative plant biology. Volume 64:Issue 8(2022)
• Page Start: 1614
• Page End: 1630
• Publication Date: 2022-07-28
• Subjects: brassinosteroid -- divergence -- grain shape -- natural variation -- rice; Plants -- Periodicals; Plants -- China -- Periodicals; Electronic journals; 580.5
• DOI: 10.1111/jipb.13322
• Languages: English
• ISSNs: 1672-9072

Abstract

ABSTRACT: Japonica / geng and indica / xian are two major rice ( Oryza sativa ) subspecies with multiple divergent traits, but how these traits are related and interact within each subspecies remains elusive. Brassinosteroids (BRs) are a class of steroid phytohormones that modulate many important agronomic traits in rice. Here, using different physiological assays, we revealed that japonica rice exhibits an overall lower BR sensitivity than indica . Extensive screening of BR signaling genes led to the identification of a set of genes distributed throughout the primary BR signaling pathway with divergent polymorphisms. Among these, we demonstrate that the C38/T variant in BR Signaling Kinase2 ( OsBSK2 ), causing the amino acid change P13L, plays a central role in mediating differential BR signaling in japonica and indica rice. OsBSK2 L13 in indica plays a greater role in BR signaling than OsBSK2 P13 in japonica by affecting the auto‐binding and protein accumulation of OsBSK2. Finally, we determined that OsBSK2 is involved in a number of divergent traits in japonica relative to indica rice, including grain shape, tiller number, cold adaptation, and nitrogen‐use efficiency. Our study suggests that the natural variation in OsBSK2 plays a key role in the divergence of BR signaling, which underlies multiple divergent traits between japonica and indica . Abstract : Rice consists of two major subspecies, indica/xian and japonica/geng . Japonica varieties exhibit lower sensitivities to brassinosteroid phytohormones than indica due to the variations in brassinosteroid signaling genes including OsBSK2, which contributes to the co‐divergence of multiple agronomic traits such as grain shape, cold sensitivity, and nitrogen utilization.