J Integr Plant Biol. ›› 2020, Vol. 62 ›› Issue (6): 793-811.DOI: 10.1111/jipb.12914

Special Issue: Hormone signaling

• Cell and Developmental Biology • Previous Articles     Next Articles

Oryza sativa mediator subunit OsMED25 interacts with OsBZR1 to regulate brassinosteroid signaling and plant architecture in rice

Yuekun Ren1,2†, Xiaojie Tian1†, Shuyu Li3, Enyang Mei1,2, Mingliang He1,2, Jiaqi Tang1,2, Min Xu1,2, Xiufeng Li1, Zhenyu Wang1, Chuanyou Li3,4 and Qingyun Bu1,4*   

  1. 1Northeast Institute of Geography and Agroecology, Key Laboratory of Soybean Molecular Design Breeding, Chinese Academy of Sciences, Harbin 150081, China
    2University of Chinese Academy of Sciences, Beijing 100049, China
    3State Key Laboratory of Plant Genomics and National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
    4The Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing 100101, China

    These authors contributed equally to this work.
    *Corresponding author:
    Email: Qingyun Bu (buqingyun@iga.ac.cn)
  • Received:2020-01-07 Accepted:2020-01-26 Online:2020-01-28 Published:2020-06-01


Brassinosteroids (BRs) are plant‐specific steroid hormones which regulate plant growth, development, and adaptation. Transcriptional regulation plays key roles in plant hormone signaling. A mediator can serve as a bridge between gene‐specific transcription factors and the RNA polymerase machinery, functioning as an essential component in regulating the transcriptional process. However, whether a mediator is involved in BR signaling is unknown. Here, we discovered that Oryza sativa mediator subunit 25 (OsMED25) is an important regulator of rice BR signaling. Phenotypic analyses showed that the OsMED25‐RNAi and osmed25 mutant presented erect leaves, as observed in BR‐deficient mutants. In addition, the OsMED25‐RNAi and osmed25 mutant exhibited decreased BR sensitivity. Genetic analysis indicated that OsMED25‐RNAi could suppress the enhanced BR signaling phenotype of Osbzr1‐D . Further biochemical analysis showed that OsMED25 interacts with OsBZR1 in vivo , and OsMED25 is enriched on the promoter of OsBZR1 target genes. RNA sequencing analysis indicated that OsMED25 affects the expression of approximately 45% of OsBZR1‐regulated genes and mainly functions as a corepressor of OsBZR1. Together, these findings revealed that OsMED25 regulates rice BR signaling by interacting with OsBZR1 and modulating the expression of OsBZR1 target genes, thus expanding our understanding of the roles of mediators in plant hormone signaling.

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