J Integr Plant Biol. ›› 2020, Vol. 62 ›› Issue (8): 1093-1111.DOI: 10.1111/jipb.12915

Special Issue: Hormone signaling

• Cell and Developmental Biology • Previous Articles     Next Articles

Brassinosteroids regulate outer ovule integument growth in part via the control of INNER NO OUTER by BRASSINOZOLE-RESISTANT family transcription factors

Dandan Jia1, Lian‐Ge Chen1, Guimin Yin1, Xiaorui Yang2, Zhihua Gao1, Yi Guo1, Yu Sun1 and Wenqiang Tang1*   

  1. 1Ministry of Education Key Laboratory of Molecular and Cellular Biology, Hebei Collaboration Innovation Center for Cell Signaling, Hebei Key Laboratory of Molecular and Cellular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang 050024, China
    2College of Bioscience & Bioengineering, Hebei University of Science and Technology, Shijiazhuang 050018, China

    *Correspondence: Wenqiang Tang (tangwq@mail.hebtu.edu.cn)
  • Received:2020-01-17 Accepted:2020-01-27 Online:2020-02-03 Published:2020-08-01


Brassinosteroids (BRs) play important roles in regulating plant reproductive processes. BR signaling or BR biosynthesis null mutants do not produce seeds under natural conditions, but the molecular mechanism underlying this infertility is poorly understood. In this study, we report that outer integument growth and embryo sac development were impaired in the ovules of the Arabidopsis thaliana BR receptor null mutant bri1‐116 . Gene expression and RNA‐seq analyses showed that the expression of INNER NO OUTER (INO ), an essential regulator of outer integument growth, was significantly reduced in the bri1‐116 mutant. Increased INO expression due to overexpression or increased transcriptional activity of BRASSINAZOLE‐RESISTANT 1 (BZR1) in the mutant alleviated the outer integument growth defect in bri1‐116 ovules, suggesting that BRs regulate outer integument growth partially via BZR1‐mediated transcriptional regulation of INO . Meanwhile, INO expression in bzr‐h , a null mutant for all BZR1 family genes, was barely detectable; and the outer integument of bzr‐h ovules had much more severe growth defects than those of the bri1‐116 mutant. Together, our findings establish a new role for BRs in regulating ovule development and suggest that BZR1 family transcription factors might regulate outer integument growth through both BRI1‐dependent and BRI1‐independent pathways.

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