Kiwifruit is an important fruit crop that is highly sensitive to environmental stresses,such as drought,heat,cold,water logging and phytopathogens.Therefore it is indispensable to identify stress-responsive candidate ...Kiwifruit is an important fruit crop that is highly sensitive to environmental stresses,such as drought,heat,cold,water logging and phytopathogens.Therefore it is indispensable to identify stress-responsive candidate genes in kiwifruit cultivars for the stress resistance improvement.Here we report the isolation and characterization of a novel kiwifruit R1R2R3-MYB homolog(AcMYB3R)whose expression was induced by drought,salinity and cold stress.In vitro assays showed that AcMYB3R is a nuclear protein with transcriptional activation activity by binding to the cis-element of the kiwifruit orthologue of G2/M phase-specific gene KNOLLE.The Arabidopsis transgenic plants overexpressing AcMYB3R showed drastically enhanced tolerance to drought and salt stress.The expressions of stress-responsive genes such as RD29A,RD29B,COR15A and RD22 were prominently up-regulated by ectopic expression of Ac MYB3R.Our study provides a valuable piece of information for functional genomics studies of kiwifruit and molecular breeding in improving stress tolerance for crop production.展开更多
The alternative splicing of select genes is an important mechanism to regulate responses to endogenous and environmental signals in plants.However,the role of alternative splicing in regulating fruit ripening remains ...The alternative splicing of select genes is an important mechanism to regulate responses to endogenous and environmental signals in plants.However,the role of alternative splicing in regulating fruit ripening remains unclear.Here,we discovered that MaMYB16L,an R1-type MYB transcription factor,undergoes alternative splicing and generates two transcripts,the full-length isoform MaMYB16L and a truncated form MaMYB16S,in banana fruit.During banana fruit ripening,the alternative splicing process intensifies with downregulated MaMYB16L and upregulated MaMYB16S.Moreover,MaMYB16L is a transcriptional repressor that directly binds with the promoters of many genes associated with starch degradation and MaDREB2,a positive ripening regulator,and represses their expression.In contrast,MaMBY16S lacks a DNA-binding domain but competitively combines and forms non-functional heterodimers with functional MaMYB16L.MaMYB16L-MaMYB16S heterodimers decrease the binding capacity and transrepression activity of MaMYB16L.The downregulation of MaMYB16L and the upregulation of MaMYB16S,that is,a decreased ratio of active to non-active isoforms,facilitates the activation of ripening-related genes and thereby promotes fruit ripening.Furthermore,the transient overexpression of MaMYB16S promotes banana fruit ripening,whereas the overexpression of MaMYB16L delays this process.Therefore,the alternative splicing of MaMYB16L might generate a self-controlled regulatory loop to regulate banana fruit ripening.展开更多
基金financially supported by the National Natural Science Foundation of China (31471157 and 31700266)
文摘Kiwifruit is an important fruit crop that is highly sensitive to environmental stresses,such as drought,heat,cold,water logging and phytopathogens.Therefore it is indispensable to identify stress-responsive candidate genes in kiwifruit cultivars for the stress resistance improvement.Here we report the isolation and characterization of a novel kiwifruit R1R2R3-MYB homolog(AcMYB3R)whose expression was induced by drought,salinity and cold stress.In vitro assays showed that AcMYB3R is a nuclear protein with transcriptional activation activity by binding to the cis-element of the kiwifruit orthologue of G2/M phase-specific gene KNOLLE.The Arabidopsis transgenic plants overexpressing AcMYB3R showed drastically enhanced tolerance to drought and salt stress.The expressions of stress-responsive genes such as RD29A,RD29B,COR15A and RD22 were prominently up-regulated by ectopic expression of Ac MYB3R.Our study provides a valuable piece of information for functional genomics studies of kiwifruit and molecular breeding in improving stress tolerance for crop production.
基金supported by the National Natural Science Foundation of China(Nos.31830070,31871856,31772041)the Science and Technology Planning Project of Guangzhou(Nos.201804020041,201904010014)National Basic Research Program of China(No.2013CB127104).
文摘The alternative splicing of select genes is an important mechanism to regulate responses to endogenous and environmental signals in plants.However,the role of alternative splicing in regulating fruit ripening remains unclear.Here,we discovered that MaMYB16L,an R1-type MYB transcription factor,undergoes alternative splicing and generates two transcripts,the full-length isoform MaMYB16L and a truncated form MaMYB16S,in banana fruit.During banana fruit ripening,the alternative splicing process intensifies with downregulated MaMYB16L and upregulated MaMYB16S.Moreover,MaMYB16L is a transcriptional repressor that directly binds with the promoters of many genes associated with starch degradation and MaDREB2,a positive ripening regulator,and represses their expression.In contrast,MaMBY16S lacks a DNA-binding domain but competitively combines and forms non-functional heterodimers with functional MaMYB16L.MaMYB16L-MaMYB16S heterodimers decrease the binding capacity and transrepression activity of MaMYB16L.The downregulation of MaMYB16L and the upregulation of MaMYB16S,that is,a decreased ratio of active to non-active isoforms,facilitates the activation of ripening-related genes and thereby promotes fruit ripening.Furthermore,the transient overexpression of MaMYB16S promotes banana fruit ripening,whereas the overexpression of MaMYB16L delays this process.Therefore,the alternative splicing of MaMYB16L might generate a self-controlled regulatory loop to regulate banana fruit ripening.
