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...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 GSK3-1ike kinases involved in BR signaling, bin2-3 bill 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, SOCl, 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.展开更多
Growth inhibition and cold-acclimation strategies help plants withstand cold stress,which adversely affects growth and survival.PHYTOCHROME B(phyB)regulates plant growth through perceiving both light and ambient tempe...Growth inhibition and cold-acclimation strategies help plants withstand cold stress,which adversely affects growth and survival.PHYTOCHROME B(phyB)regulates plant growth through perceiving both light and ambient temperature signals.However,the mechanism by which phyB mediates the plant response to cold stress remains elusive.Here,we show that the key transcription factors mediating cold acclimation,C-REPEAT BINDING FACTORs(CBFs),interact with PHYTOCHROME-INTERACTING FACTOR 3(PIF3)under cold stress,thus attenuating the mutually assured destruction of PIF3–phyB.Cold-stabilized phyB acts downstream of CBFs to positively regulate freezing tolerance by modulating the expression of stress-responsive and growth-related genes.Consistent with this,phyB mutants exhibited a freezing-sensitive phenotype,whereas phyB-overexpression transgenic plants displayed enhanced freezing tolerance.Further analysis showed that the PIF1,PIF4,and PIF5 proteins,all of which negatively regulate plant freezing tolerance,were destabilized by cold stress in a phytochrome-dependent manner.Collectively,our study reveals that CBFs–PIF3–phyB serves as an important regulatory module for modulating plant response to cold stress.展开更多
文摘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 GSK3-1ike kinases involved in BR signaling, bin2-3 bill 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, SOCl, 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.
基金This work was supported by grants from the Ministry of Agriculture of China,China(2016ZX08009003-002)the National Natural Science Foundation of China,China(31872658,31921001)Discipline Program of Beijing Outstanding University,China.
文摘Growth inhibition and cold-acclimation strategies help plants withstand cold stress,which adversely affects growth and survival.PHYTOCHROME B(phyB)regulates plant growth through perceiving both light and ambient temperature signals.However,the mechanism by which phyB mediates the plant response to cold stress remains elusive.Here,we show that the key transcription factors mediating cold acclimation,C-REPEAT BINDING FACTORs(CBFs),interact with PHYTOCHROME-INTERACTING FACTOR 3(PIF3)under cold stress,thus attenuating the mutually assured destruction of PIF3–phyB.Cold-stabilized phyB acts downstream of CBFs to positively regulate freezing tolerance by modulating the expression of stress-responsive and growth-related genes.Consistent with this,phyB mutants exhibited a freezing-sensitive phenotype,whereas phyB-overexpression transgenic plants displayed enhanced freezing tolerance.Further analysis showed that the PIF1,PIF4,and PIF5 proteins,all of which negatively regulate plant freezing tolerance,were destabilized by cold stress in a phytochrome-dependent manner.Collectively,our study reveals that CBFs–PIF3–phyB serves as an important regulatory module for modulating plant response to cold stress.
