Tian et al. report a link between classic brassinosteroid signaling and the mitogen-activated protein kinase pathway in regulation of rice architecture and seed size. Plant Cell https://doi.org/10.1093/plcell/koab137
By Xiaojie Tian, Mingliang He, Enyang Mei, Baowen Zhang, Jiaqi Tang, Min Xu, Jiali Liu, Xiufeng Li, Zhenyu Wang, Wenqiang Tang, Qingjie Guan and Qingyun Bu.
Background: Rice is an important food crop and feeds more than half of the world population. Rice architecture and seed size are closely related to yield. Plant hormone brassinosteroid signaling and the mitogen-activated protein kinase cascade are two major regulatory pathways that control rice architecture and seed size.
Question: To increase the rice yield and breed elite cultivars, it is necessary to identify the critical genes corresponding to architecture and seed size, and utilize them in breeding. Accordingly, we aimed to study the brassinosteroid and mitogen-activated protein kinase signaling pathways in detail, and characterize the major genes involved in the regulation of rice architecture and grain size.
Findings: We found that the transcription factor WRKY53 controls both leaf angle and seed size. GSK2 and BZR1 are two well-known components in rice brassinosteroid signaling. WRKY53 functions downstream of OsGSK2 and in parallel with OsBZR1, and serves as a novel component in brassinosteroid signaling. At the same time, OsWRKY53 is a direct substrate of the mitogen-activated protein kinase pathway. These results suggest that OsWRKY53 might control seed size and leaf angle via mediating the cross-talk between brassinosteroids and the mitogen-activated protein kinase pathway.
Next steps: Given that WRKY53 is a transcription factor, we plan to identify the downstream target genes of OsWRKY53, and further investigate the WRKY53-mediated regulatory network involved in rice architecture and seed size control.
Xiaojie Tian, Mingliang He, Enyang Mei, Baowen Zhang, Jiaqi Tang, Min Xu, Jiali Liu, Xiufeng Li, Zhenyu Wang, Wenqiang Tang, Qingjie Guan and Qingyun Bu. (2021). WRKY53 Integrates Classic Brassinosteroid Signaling and the Mitogen-Activated Protein Kinase Pathway to Regulate Rice Architecture and Seed Size. Plant Cell. https://doi.org/10.1093/plcell/koab137