大白菜叶片黑芥子酶TGG基因家族的鉴定与功能分析OA

Myrosinase(TGG)is a specialized glycoside hydrolase that catalyzes the hydrolysis of glucosinolates(GSLs),which are important secondary metabolites in cruciferous vegetables,to generate various biologically active degradation products.It plays vital roles in determining the quality,flavor,nutritional health value,and defense responses of cruciferous vegetables.To identify the TGG gene family in Chinese cabbage and investigate its role in glucosinolate hydrolysis,this study employed bioinformatic methods and successully identified 10 BrTGGs in Chinese cabbage,which are unevenly distributed across 5 chromosomes.Promoter analysis revealed that the promoter regions of this gene family are enriched with numerous cis-acting elements associated with abiotic stress responses.Gene cloning results revealed that six BrTGGs genes exhibit high sequence conservation in their functional catalytic domains,and all contain the evolutionarily conserved glutamine residue that acts as the critical catalytic site for myrosinase hydrolytic activity.The relative expression levels of BrTGGs members were significantly higher in leaf tissues than in root tissues.Specifically,BrTGG5 and BrTGG8/9 exhibited relatively high expression levels in leaf tissues,while BrTGG2,BrTGG3,and BrTGG8/9 showed relatively high expression levels in root tissues.In vitro enzyme activity assays showed that the total glucosinolate degradation capability was enhanced in BrTGGs overexpressing lines,but reduced in plants subjected to virus-induced gene silencing(VIGS),confirming that the identified BrTGGs possess glucosinolate hydrolase activity.These findings establish a significant foundation for further in-depth investigation into the biological functions of these TGG genes in stress resistance and developmental processes in Chinese cabbage.