The yam Dioscorea alata L.is widely cultivated globally.Purple-fleshed varieties of this important crop have enhanced market value due to their high anthocyanin contents,but how anthocyanin biosynthesis in D.alata tub...The yam Dioscorea alata L.is widely cultivated globally.Purple-fleshed varieties of this important crop have enhanced market value due to their high anthocyanin contents,but how anthocyanin biosynthesis in D.alata tubers is regulated remains poorly understood.In this study,we identified and functionally validated key transcription factors that regulate anthocyanin biosynthesis based on a comparative transcriptome and metabolome analysis of three D.alata cultivars with different colored tubers(dark purple,light purple,and white).The anthocyanin glycoside cyanidin-3-O-(2′′-O-glucosyl)glucoside was abundant during early tuber development,and we determined that its accumulation is regulated in opposite manners by two R2R3-MYB transcription factors:DaMYB75 and DaMYB56.Yeast two-hybrid and bimolecular fluorescence complementation assays in Nicotiana benthamiana and co-expression assays in D.alata demonstrated that DaMYB75 promotes anthocyanin biosynthesis by specifically activating the promoter of the late anthocyanin biosynthesis gene DaANS and enhancing its expression through an interaction with DabHLH72.By contrast,DaMYB56 is a negative regulator of anthocyanin biosynthesis that binds to the DaANS promoter together with DabHLH72.Furthermore,the methylation levels of the DaMYB75 promoter were significantly lower in purple tubers than in white tubers.These findings shed light on the regulation of anthocyanin biosynthesis by MYBs and provide the basis for genetically improving anthocyanin content in D.alata.展开更多
Background:This study aimed to comprehensively elucidate the hepatotoxic effects of Dioscorea bulbifera L.(DBL)in mice and to explore the underlying molecular mechanisms.Methods:Mice were administered different doses ...Background:This study aimed to comprehensively elucidate the hepatotoxic effects of Dioscorea bulbifera L.(DBL)in mice and to explore the underlying molecular mechanisms.Methods:Mice were administered different doses of DBL via intragastric gavage for 21 days.Organ indices of multiple organs were then measured,and histopathological changes were systematically evaluated.Particular attention was paid to biochemical markers and hepatic histopathological alterations associated with liver injury.Subsequently,the composition of the gut microbiota in colonic contents was analyzed using 16S rDNA sequencing,and the levels of short-chain fatty acids(SCFAs)were determined by gas chromatography(GC).Furthermore,protein expression levels of YinYang 1(YY1),Farnesoid X Receptor(FXR),Nuclear factor erythroid 2-related factor 2(Nrf2),and bile acids(BAs)-related proteins in the liver were assessed by Western blot analysis.Results:Our findings revealed that DBL induced varying degrees of multi-organ toxicity in mice,with the most pronounced hepatotoxicity observed.Liver injury was induced in a dose-dependent manner,accompanied by increased hepatic inflammation and oxidative stress,as well as enhanced hepatocyte apoptosis.Furthermore,DBL may modulate the YY1-FXR/Nrf2 signaling pathway,leading to upregulation of BAs-related proteins such as cholesterol 7α-hydroxylase(CYP7A1),while downregulating other BAs-related proteins,including sodium taurocholate cotransporting polypeptide(NTCP),bile salt export pump(BSEP),multidrug resistance protein 2(MRP2),and P-glycoprotein(P-gp).These changes promoted excessive BAs synthesis and impaired the excretion and reabsorption of BAs,ultimately disturbing BAs homeostasis.Additionally,DBL induces gut microbiota dysbiosis and reduces SCFAs production,leading to intestinal damage and disruption of intestinal barrier integrity.Conclusion:DBL-induced hepatotoxicity may be associated with altered expression of the YY1-FXR/Nrf2 signaling pathway and BAs–related proteins,accompanied by increased hepatic BAs accumulation and gut microbiota dysbiosis.展开更多
基金supported by the National Natural Science Foundation of China(32460767)Jiangxi Provincial Key Research and Development Program(20232BBF60007)Jiangxi Provincial Natural Science Foundation(20224BAB205024).
文摘The yam Dioscorea alata L.is widely cultivated globally.Purple-fleshed varieties of this important crop have enhanced market value due to their high anthocyanin contents,but how anthocyanin biosynthesis in D.alata tubers is regulated remains poorly understood.In this study,we identified and functionally validated key transcription factors that regulate anthocyanin biosynthesis based on a comparative transcriptome and metabolome analysis of three D.alata cultivars with different colored tubers(dark purple,light purple,and white).The anthocyanin glycoside cyanidin-3-O-(2′′-O-glucosyl)glucoside was abundant during early tuber development,and we determined that its accumulation is regulated in opposite manners by two R2R3-MYB transcription factors:DaMYB75 and DaMYB56.Yeast two-hybrid and bimolecular fluorescence complementation assays in Nicotiana benthamiana and co-expression assays in D.alata demonstrated that DaMYB75 promotes anthocyanin biosynthesis by specifically activating the promoter of the late anthocyanin biosynthesis gene DaANS and enhancing its expression through an interaction with DabHLH72.By contrast,DaMYB56 is a negative regulator of anthocyanin biosynthesis that binds to the DaANS promoter together with DabHLH72.Furthermore,the methylation levels of the DaMYB75 promoter were significantly lower in purple tubers than in white tubers.These findings shed light on the regulation of anthocyanin biosynthesis by MYBs and provide the basis for genetically improving anthocyanin content in D.alata.
基金supported by the National Natural Science Foundation of China(82204790)Shaanxi University of Chinese Medicine Science and Technology Program(2024-LJRC-04)+1 种基金Shaanxi Province Natural Science Foundation(2024JC-YBMS-759)Qinchuangyuan TCM Industry Innovation Project(L2024-QCY-ZYYJJQ-X29).
文摘Background:This study aimed to comprehensively elucidate the hepatotoxic effects of Dioscorea bulbifera L.(DBL)in mice and to explore the underlying molecular mechanisms.Methods:Mice were administered different doses of DBL via intragastric gavage for 21 days.Organ indices of multiple organs were then measured,and histopathological changes were systematically evaluated.Particular attention was paid to biochemical markers and hepatic histopathological alterations associated with liver injury.Subsequently,the composition of the gut microbiota in colonic contents was analyzed using 16S rDNA sequencing,and the levels of short-chain fatty acids(SCFAs)were determined by gas chromatography(GC).Furthermore,protein expression levels of YinYang 1(YY1),Farnesoid X Receptor(FXR),Nuclear factor erythroid 2-related factor 2(Nrf2),and bile acids(BAs)-related proteins in the liver were assessed by Western blot analysis.Results:Our findings revealed that DBL induced varying degrees of multi-organ toxicity in mice,with the most pronounced hepatotoxicity observed.Liver injury was induced in a dose-dependent manner,accompanied by increased hepatic inflammation and oxidative stress,as well as enhanced hepatocyte apoptosis.Furthermore,DBL may modulate the YY1-FXR/Nrf2 signaling pathway,leading to upregulation of BAs-related proteins such as cholesterol 7α-hydroxylase(CYP7A1),while downregulating other BAs-related proteins,including sodium taurocholate cotransporting polypeptide(NTCP),bile salt export pump(BSEP),multidrug resistance protein 2(MRP2),and P-glycoprotein(P-gp).These changes promoted excessive BAs synthesis and impaired the excretion and reabsorption of BAs,ultimately disturbing BAs homeostasis.Additionally,DBL induces gut microbiota dysbiosis and reduces SCFAs production,leading to intestinal damage and disruption of intestinal barrier integrity.Conclusion:DBL-induced hepatotoxicity may be associated with altered expression of the YY1-FXR/Nrf2 signaling pathway and BAs–related proteins,accompanied by increased hepatic BAs accumulation and gut microbiota dysbiosis.
