Brassinosteroids Regulate the Differential Growth of Arabidopsis Hypocotyls through Auxin Signaling Components IAA19 and ARF7

作     者：Xiao-Yi Zhou Li Song Hong-Wei Xue 

作者机构：National Key Laboratory of Plant Molecular Genetics Institute of Plant Physiology and Ecology Shanghai Institutes for Biological Sciences Chinese Academy of Sciences 300 Fenglin Road 200032 Shanghai China 

出 版 物：《Molecular Plant》 (分子植物（英文版）)

年 卷 期：2013年第6卷第3期

页      面：887-904页

核心收录：

学科分类：0710[理学-生物学] 071001[理学-植物学] 07[理学] 09[农学] 0901[农学-作物学] 

基　　金：This study was supported by the National Science Foundation of China (Grant Nos: 91117009 and 90717001).Wethank Dr Kotaro T. Yamamoto (Hokkaido University) for the gifts of msg2-1 seeds  Dr Zhi-Yong Wang (Stanford University) for providing bzrl-D seeds and seeds of pBZRI::mBZR1-CFP transgenic plants  Prof. Hong-Quan Yang (Shanghai Jiao Tong University) for axr2-1 seeds  and Dr Jian-Ming Li (University of Michigan) for det2-1 seeds. No conflict of interest declared 

主　　题：brassinosteroids (BRs) auxin IAA19 ARF7 differential growth Arabidopsis. 

摘      要：Brassinosteroids （BRs） are an important class of phytohormones which regulates a wide range of physiological processes. Genetic and physiological studies have revealed that BR responses usually depend on an intact auxin signaling pathway. Here, we demonstrate that high BR concentration or enhanced BR signaling induce the differential growth of etiolated hypocotyls and result in the morphological changes, while auxin-resistant mutants, msg2 （dominant mutant of IAA19） and arf7, are insensitive to the BR effect and can partially suppress the phenotype of bzrl-D （dominant mutant of BZR1 with enhanced BR signaling）. Interestingly, BZR1 protein can directly bind to the promoter regions of both IAA19 and ARFT, indicating that IAA19 and ARF7 mediate the BR-induced differential growth by serving as direct targets of BZR1. Systemic microarray analysis revealed that a number of BR-responsive genes showed reduced BR response in msg2, confirming that BR employs auxin signaling components IAA19 and ARF7 to modulate the specific downstream processes. These results provide informative clues on the crosstalk of BR-auxin signaling and the mechanisms of BR-auxin effects in regulating differential growth.