title: BZR1 Positively Regulates Freezing Tolerance via CBF-Dependent and CBF-Independent Pathways in Arabidopsis.
abstract: Cold stress is a major environmental factor that adversely affects plant growth and development. The C-repeat binding factor/DRE binding factor 1 (CBF/DREB1) transcriptional regulatory cascade has been shown to play important roles in plant response to cold. Here we demonstrate that two key components of brassinosteroid (BR) signaling modulate freezing tolerance of Arabidopsis plants. The loss-of-function mutant of the GSK3-like kinases involved in BR signaling, bin2-3 bil1 bil2, showed increased freezing tolerance, whereas overexpression of BIN2 resulted in hypersensitivity to freezing stress under both non-acclimated and acclimated conditions. By contrast, gain-of-function mutants of the transcription factors BZR1 and BES1 displayed enhanced freezing tolerance, and consistently cold treatment could induce the accumulation of dephosphorylated BZR1. Biochemical and genetic analyses showed that BZR1 acts upstream of CBF1 and CBF2 to directly regulate their expression. Moreover, we found that BZR1 also regulated other COR genes uncoupled with CBFs, such as WKRY6, PYL6, SOC1, JMT, and SAG21, to modulate plant response to cold stress. Consistently, wrky6 mutants showed decreased freezing tolerance. Taken together, our results indicate that BZR1 positively modulates plant freezing tolerance through CBF-dependent and CBF-independent pathways.
authors.affiliation: State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Li
authors.affiliation: State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China.
authors.forename: Keyi
authors.initials: K
authors.lastname: Ye
authors.affiliation: State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China.
authors.forename: Yiting
authors.initials: Y
authors.lastname: Shi
authors.affiliation: State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China.
authors.forename: Jinkui
authors.initials: J
authors.lastname: Cheng
authors.affiliation: State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China.
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China. Electronic address: yangshuhua@cau.edu.cn.
authors.forename: Shuhua
authors.initials: S
authors.lastname: Yang
mesh_terms: D017360:Arabidopsis / Q000378:metabolism* / Q000502:physiology; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins; D005615:Freezing; D018506:Gene Expression Regulation, Plant / Q000235:genetics / Q000502:physiology; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D011494:Protein Kinases; D014157:Transcription Factors; C454444:BZR1 protein, Arabidopsis; C114578:DREB1A protein, Arabidopsis; C448985:At4g18710 protein, Arabidopsis
keywords: Arabidopsis; BIN2; BZR1; CBF; freezing tolerance