The transcription factor VaCBF2, which interacts with C-repeat/DRE and its promoter, was isolated from Vitis amurensis. The VaCBF2 amino acid sequence contained a conserved AP2 domain of 56 amino acids and a potential...The transcription factor VaCBF2, which interacts with C-repeat/DRE and its promoter, was isolated from Vitis amurensis. The VaCBF2 amino acid sequence contained a conserved AP2 domain of 56 amino acids and a potential nuclear localization sequence. The sequence of VaCBF2 showed a high level of homology with other CBF2 family members. Phylogenetic analysis showed that the amino acid sequences may be CBF2 proteins with evolutionary relationship. Quantitative reverse-transcription polymerase chain reaction analysis indicated that the expression of VaCBF2 gene in tissues (roots, stems, leaves, and petioles) was induced by low temperature, high salinity, and application of abscisic acid and salicylic acid in a time-dependent manner but to different extents in the cold-hardy V. amurensis and the less cold-hardy Vitis vinifera. The presence of cis-elements such as MYC and ABRE in VaCBF2 promoter further confirmed that this promoter was a component of the CBF transduction pathway involved in plant response to multiple stresses.展开更多
Plant growth and development are significantly hampered in saline environments,limiting agricultural productivity.Thus,it is crucial to unravel the mechanism underlying plant responses to salt stress.β-1,4-Galactan(g...Plant growth and development are significantly hampered in saline environments,limiting agricultural productivity.Thus,it is crucial to unravel the mechanism underlying plant responses to salt stress.β-1,4-Galactan(galactan),which forms the side chains of pectic rhamnogalacturonan I,enhances plant sensitivity to high-salt stress.Galactan is synthesized by GALACTAN SYNTHASE1(GALS1).We previously showed that Na Cl relieves the direct suppression of GALS1 transcription by the transcription factors BPC1 and BPC2 to induce the excess accumulation of galactan in Arabidopsis(Arabidopsis thaliana).However,how plants adapt to this unfavorable environment remains unclear.Here,we determined that the transcription factors CBF1,CBF2,and CBF3 directly interact with the GALS1 promoter and repress its expression,leading to reduced galactan accumulation and enhanced salt tolerance.Salt stress enhances the binding of CBF1/CBF2/CBF3 to the GALS1 promoter by inducing CBF1/CBF2/CBF3 transcription and accumulation.Genetic analysis suggested that CBF1/CBF2/CBF3 function upstream of GALS1 to modulate salt-induced galactan biosynthesis and the salt response.CBF1/CBF2/CBF3 and BPC1/BPC2 function in parallel to regulate GALS1 expression,thereby modulating the salt response.Our results reveal a mechanism in which salt-activated CBF1/CBF2/CBF3 inhibit BPC1/BPC2-regulated GALS1 expression to alleviate galactan-induced salt hypersensitivity,providing an activation/deactivation fine-tune mechanism for dynamic regulation of GALS1 expression under salt stress in Arabidopsis.展开更多
文摘The transcription factor VaCBF2, which interacts with C-repeat/DRE and its promoter, was isolated from Vitis amurensis. The VaCBF2 amino acid sequence contained a conserved AP2 domain of 56 amino acids and a potential nuclear localization sequence. The sequence of VaCBF2 showed a high level of homology with other CBF2 family members. Phylogenetic analysis showed that the amino acid sequences may be CBF2 proteins with evolutionary relationship. Quantitative reverse-transcription polymerase chain reaction analysis indicated that the expression of VaCBF2 gene in tissues (roots, stems, leaves, and petioles) was induced by low temperature, high salinity, and application of abscisic acid and salicylic acid in a time-dependent manner but to different extents in the cold-hardy V. amurensis and the less cold-hardy Vitis vinifera. The presence of cis-elements such as MYC and ABRE in VaCBF2 promoter further confirmed that this promoter was a component of the CBF transduction pathway involved in plant response to multiple stresses.
基金supported by grants from the National Natural Science Foundation of China(32001445)。
文摘Plant growth and development are significantly hampered in saline environments,limiting agricultural productivity.Thus,it is crucial to unravel the mechanism underlying plant responses to salt stress.β-1,4-Galactan(galactan),which forms the side chains of pectic rhamnogalacturonan I,enhances plant sensitivity to high-salt stress.Galactan is synthesized by GALACTAN SYNTHASE1(GALS1).We previously showed that Na Cl relieves the direct suppression of GALS1 transcription by the transcription factors BPC1 and BPC2 to induce the excess accumulation of galactan in Arabidopsis(Arabidopsis thaliana).However,how plants adapt to this unfavorable environment remains unclear.Here,we determined that the transcription factors CBF1,CBF2,and CBF3 directly interact with the GALS1 promoter and repress its expression,leading to reduced galactan accumulation and enhanced salt tolerance.Salt stress enhances the binding of CBF1/CBF2/CBF3 to the GALS1 promoter by inducing CBF1/CBF2/CBF3 transcription and accumulation.Genetic analysis suggested that CBF1/CBF2/CBF3 function upstream of GALS1 to modulate salt-induced galactan biosynthesis and the salt response.CBF1/CBF2/CBF3 and BPC1/BPC2 function in parallel to regulate GALS1 expression,thereby modulating the salt response.Our results reveal a mechanism in which salt-activated CBF1/CBF2/CBF3 inhibit BPC1/BPC2-regulated GALS1 expression to alleviate galactan-induced salt hypersensitivity,providing an activation/deactivation fine-tune mechanism for dynamic regulation of GALS1 expression under salt stress in Arabidopsis.
