Arabidopsis (Arabidopsis thaliana) WRKY33 is a key transcription factor in pathogen-induced defense signaling, but its function in abiotic stresses remains largely unclear. In this study, we report on the use of a rev...Arabidopsis (Arabidopsis thaliana) WRKY33 is a key transcription factor in pathogen-induced defense signaling, but its function in abiotic stresses remains largely unclear. In this study, we report on the use of a reverse-genetic approach, as well as a yeast (Saccharomyces cerevisiae) expression system, to determine the role of WRKY33 in drought. A T-DNA insertion deletion mutant of WRKY33 is more sensitive to dehydration. Through genome-wide screening the target genes of WRKY33 in yeast, we identified 23 candidate genes including a drought tolerance gene CesA8. Further results revealed that WRKY33 repressed CesA8 expression through binding to the W-box elements of CesA8 distal promoter region and probably interacting with the transcriptional activator of CesA8, MYB46. These findings revealed the primary molecular mechanism underlying the function of WRKY33 in response to展开更多
The tryptophan(Trp)-derived plant secondary metabolites,including camalexin,4-hydroxyindole-3-carbonylnitrile,and indolic glucosinolate(IGS),show broad-spectrum antifungal activity.However,the distinct regulations of ...The tryptophan(Trp)-derived plant secondary metabolites,including camalexin,4-hydroxyindole-3-carbonylnitrile,and indolic glucosinolate(IGS),show broad-spectrum antifungal activity.However,the distinct regulations of these metabolic pathways among different plant species in response to fungus infection are rarely studied.In this study,our results revealed that WRKY33 directly regulates IGS biosynthesis,notably the production of 4-methoxyindole-3-ylmethyl glucosinolate(4MI3G),conferring resistance to Alternaria brassicicola,an important pathogen which causes black spot in Brassica crops.WRKY33 directly activates the expression of CYP81F2,IGMT1,and IGMT2 to drive sidechain modification of indole-3-ylmethyl glucosinolate(I3G)to 4MI3G,in both Arabidopsis and Chinese kale(Brassica oleracea var.alboglabra Bailey).However,Chinese kale showed a more severe symptom than Arabidopsis when infected by Alternaria brassicicola.Comparative analyses of the origin and evolution of Trp metabolism indicate that the loss of camalexin biosynthesis in Brassica crops during evolution might attenuate the resistance of crops to Alternaria brassicicola.As a result,the IGS metabolic pathway mediated by WRKY33 becomes essential for Chinese kale to deter Alternaria brassicicola.Our results highlight the differential regulation of Trp-derived camalexin and IGS biosynthetic pathways in plant immunity between Arabidopsis and Brassica crops.展开更多
Anthocyanin accumulation is acknowledged as a phenotypic indicator of phosphate(Pi)starvation.However,negative regulators of this process and their molecular mechanisms remain largely unexplored.In this study,we demon...Anthocyanin accumulation is acknowledged as a phenotypic indicator of phosphate(Pi)starvation.However,negative regulators of this process and their molecular mechanisms remain largely unexplored.In this study,we demonstrate that WRKY33 acts as a negative regulator of phosphorus-status-dependent anthocyanin biosynthesis.WRKY33 regulates the expression of the gene encoding dihydroflavonol 4-reductase(DFR),a rate-limiting enzyme in anthocyanin production,both directly and indirectly.WRKY33 binds directly to the DFR promoter to repress its expression and also interferes with the MBW complex through interacting with PAP1 to indirectly influence DFR transcriptional activation.Under�Pi conditions,PHR1 interacts with WRKY33,and the protein level of WRKY33 decreases;the repression of DFR expression by WRKY33 is thus attenuated,leading to anthocyanin accumulation in Arabidopsis.Further genetic and biochemical assays suggest that PHR1 is also involved in regulating factors that affect WRKY33 protein turnover.Taken together,ourfindings reveal that Pi starvation represses WRKY33,a repressor of anthocyanin biosynthesis,tofinely tune anthocyanin biosynthesis.This‘‘double-negative logic’’regulation of phosphorus-status-dependent anthocyanin biosynthesis is required for the mainte-nance of plant metabolic homeostasis during acclimation to Pi starvation.展开更多
文摘Arabidopsis (Arabidopsis thaliana) WRKY33 is a key transcription factor in pathogen-induced defense signaling, but its function in abiotic stresses remains largely unclear. In this study, we report on the use of a reverse-genetic approach, as well as a yeast (Saccharomyces cerevisiae) expression system, to determine the role of WRKY33 in drought. A T-DNA insertion deletion mutant of WRKY33 is more sensitive to dehydration. Through genome-wide screening the target genes of WRKY33 in yeast, we identified 23 candidate genes including a drought tolerance gene CesA8. Further results revealed that WRKY33 repressed CesA8 expression through binding to the W-box elements of CesA8 distal promoter region and probably interacting with the transcriptional activator of CesA8, MYB46. These findings revealed the primary molecular mechanism underlying the function of WRKY33 in response to
基金supported by National Natural Science Foundation of China(32172593)the Ministry of Agriculture of China(2016ZX08009003-944001)Zhejiang Provincial Ten-Thousand Program for Leading Talents of Science and Technology Innovation(2018R52026)。
文摘The tryptophan(Trp)-derived plant secondary metabolites,including camalexin,4-hydroxyindole-3-carbonylnitrile,and indolic glucosinolate(IGS),show broad-spectrum antifungal activity.However,the distinct regulations of these metabolic pathways among different plant species in response to fungus infection are rarely studied.In this study,our results revealed that WRKY33 directly regulates IGS biosynthesis,notably the production of 4-methoxyindole-3-ylmethyl glucosinolate(4MI3G),conferring resistance to Alternaria brassicicola,an important pathogen which causes black spot in Brassica crops.WRKY33 directly activates the expression of CYP81F2,IGMT1,and IGMT2 to drive sidechain modification of indole-3-ylmethyl glucosinolate(I3G)to 4MI3G,in both Arabidopsis and Chinese kale(Brassica oleracea var.alboglabra Bailey).However,Chinese kale showed a more severe symptom than Arabidopsis when infected by Alternaria brassicicola.Comparative analyses of the origin and evolution of Trp metabolism indicate that the loss of camalexin biosynthesis in Brassica crops during evolution might attenuate the resistance of crops to Alternaria brassicicola.As a result,the IGS metabolic pathway mediated by WRKY33 becomes essential for Chinese kale to deter Alternaria brassicicola.Our results highlight the differential regulation of Trp-derived camalexin and IGS biosynthetic pathways in plant immunity between Arabidopsis and Brassica crops.
基金funded by the Zhejiang Provincial Natural Science Foundation of China under grant no.LR22C020003the National Key Research and Development Program of China (2022YFD2200603)+2 种基金the National Natural Science Foundation of China under grant nos.32000234 and 32172593the China Postdoctoral Science Foundation (2022M712831)funding from the State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products.
文摘Anthocyanin accumulation is acknowledged as a phenotypic indicator of phosphate(Pi)starvation.However,negative regulators of this process and their molecular mechanisms remain largely unexplored.In this study,we demonstrate that WRKY33 acts as a negative regulator of phosphorus-status-dependent anthocyanin biosynthesis.WRKY33 regulates the expression of the gene encoding dihydroflavonol 4-reductase(DFR),a rate-limiting enzyme in anthocyanin production,both directly and indirectly.WRKY33 binds directly to the DFR promoter to repress its expression and also interferes with the MBW complex through interacting with PAP1 to indirectly influence DFR transcriptional activation.Under�Pi conditions,PHR1 interacts with WRKY33,and the protein level of WRKY33 decreases;the repression of DFR expression by WRKY33 is thus attenuated,leading to anthocyanin accumulation in Arabidopsis.Further genetic and biochemical assays suggest that PHR1 is also involved in regulating factors that affect WRKY33 protein turnover.Taken together,ourfindings reveal that Pi starvation represses WRKY33,a repressor of anthocyanin biosynthesis,tofinely tune anthocyanin biosynthesis.This‘‘double-negative logic’’regulation of phosphorus-status-dependent anthocyanin biosynthesis is required for the mainte-nance of plant metabolic homeostasis during acclimation to Pi starvation.
