Novel Key Component Helps Illustrate Molecular Mechanism of Brassinosteroids Signaling

Phytohormone brassinosteroids (BRs) play important roles in regulating plant development. Studies have demonstrated, by manipulating level or sensitivity, BR can display crucial roles in regulating rice architecture and contain the enormous potential to improve rice yields. The components of BR signaling have been widely studied in Arabidopsis. Membrane-located receptor BRI1 (BR Insensitive1, a receptor-like kinase) perceives BR signal, whose activity is stimulated by BR-induced BRI1-BAK1 (BRI1-Associated Kinase1) hetero-dimerization or negatively regulated by BRI1 internalization modification with ubiquitination. So far, however, only a few components involved in rice BR signaling have been identified; and further investigations will help to illustrate the functional mechanism of BR in monocots and contribute the molecular breeding of rice architecture.

Prof. XUE Hongwei and his colleagues at CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology (SIPPE), Chinese Academy of Sciences (CAS), identify elt1-D, a gain-of-function rice mutant presenting reduced height and significantly increased tiller number and leaf inclination. Genetic analysis shows that the elt1-D phenotype results from the enhanced BR signaling. Although being well conserved with enzymatically active serine/threonine kinases, the ELT1 intercellular domain does not present kinase activity. Further analysis reveals that tissue-specific ELT1 stimulates BR signaling by suppressing endocytosis-mediated degradation of BRI1 through interaction. These results identify ELT1 as a novel key component of BR signaling, and help to illustrate the molecular mechanism of BR functions in determining distinct agricultural traits of crops. The novel findings will also facilitate functions and relevant mechanisms studies of RLKs, which lack kinase activity in various physiological processes.

The study entitled “Receptor-like protein ELT1 promotes brassinosteroid signaling through interacting with and suppressing the endocytosis-mediated degradation of receptor BRI1” has been published online in Cell Research on May 12, 2017.

The study was supported by Ministry of Science and Technology of China, the Chinese Academy of Sciences, the National Natural Science Foundation of China.

Article website: http://www.nature.com/cr/journal/vaop/ncurrent/full/cr201769a.html

Author Contact:
Dr. XUE Hongwei, Principal Investigator
CAS Center for Excellence in Molecular Plant Sciences
Shanghai Institute of Plant Physiology and Ecology (SIPPE)
Chinese Academy of Science (CAS)
Phone: (86) 21- 54924059
Fax: (86) 21- 54924015
Email: hwxue@sibs.ac.cn