Evolutionary analysis and functional characterization of SiBRI1 as a Brassinosteroid receptor gene in foxtail millet

BMC Plant Biology

Yanxiang Sun¹  Yiming Zhang¹  Sha Tang²  Xianmin Diao³  Zhiying Zhao⁴  Ruiju Wang⁴  Jiaqi Xu⁴  Wenqiang Tang⁴  Baowen Zhang⁴  Jingjing Yue⁴ 

[1] College of Life Sciences, Langfang Normal University, 065000, Langfang, China;Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, 100081, Beijing, China;Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, 100081, Beijing, China;Foxtail Millet Improvement Center of China, Institute of Millet Crops, Hebei Academy of Agricultural and Forestry Science, 050031, Shijiazhuang, China;Ministry of Education Key Laboratory of Molecular and Cellular Biology, Hebei Collaboration Innovation Center for Cell Signaling and Environmental Adaptation, Hebei Key Laboratory of Molecular and Cellular Biology, College of Life Sciences, Hebei Normal University, 050024, Shijiazhuang, Hebei, China;

关键词: Brassinosteroids;    BRI1;    Foxtail millet;    Phylogenetic analysis;   

DOI  :  10.1186/s12870-021-03081-8

来源: Springer

【 摘 要 】

Brassinosteroids (BRs) play important roles in plant growth and development. Although BR receptors have been intensively studied in Arabidopsis, those in foxtail millet remain largely unknown. Here, we show that the BR signaling function of BRASSINOSTEROID INSENSITIVE 1 (BRI1) is conserved between Arabidopsis and foxtail millet, a new model species for C4 and Panicoideae grasses. We identified four putative BR receptor genes in the foxtail millet genome: SiBRI1, SiBRI1-LIKE RECEPTOR KINASE 1 (SiBRL1), SiBRL2 and SiBRL3. Phylogenetic analysis was used to classify the BR receptors in dicots and monocots into three branches. Analysis of their expression patterns by quantitative real-time PCR (qRT-PCR) showed that these receptors were ubiquitously expressed in leaves, stems, dark-grown seedlings, roots and non-flowering spikelets. GFP fusion experiments verified that SiBRI1 localized to the cell membrane. We also explored the SiBRI1 function in Arabidopsis through complementation experiments. Ectopic overexpression of SiBRI1 in an Arabidopsis BR receptor loss-of-function mutant, bri1-116, mostly reversed the developmental defects of the mutant. When SiBRI1 was overexpressed in foxtail millet, the plants showed a drooping leaf phenotype and root development inhibition, lateral root initiation inhibition, and the expression of BR synthesis genes was inhibited. We further identified BRI1-interacting proteins by immunoprecipitation (IP)-mass spectrometry (MS). Our results not only demonstrate that SiBRI1 plays a conserved role in BR signaling in foxtail millet but also provide insight into the molecular mechanism of SiBRI1.

【 授权许可】

CC BY