大齿牛果藤中CHS基因家族鉴定与分析OA

Nekemias grossedentata,the original plant of vine tea,is rich in flavonoids,in which chalcone synthase (CHS) acts as the first key rate-limiting enzyme in the biosynthetic pathway. Based on genome and transcriptome data,this study systematically identified and comprehensively analyzed the genome-wide CHS gene family for the first time. The results revealed a total of 28 CHS members (NgCHS),which were unevenly distributed across seven chromo-somes,with evident tandem duplication events,suggesting that tandem duplication serves as the primary driving force for NgCHS family expansion. Phylogenetic analysis classified the CHS genes into four subgroups,with NgCHS2 and NgCHS7 clustering together with AtCHS from Arabidopsis thaliana,suggesting that they are candidate functional CHS genes. Conserved motif and gene structure analysis confirmed that the family was highly conserved. Cis-acting element analysis showed that NgCHS may be involved in light response,hormone regulation and abiotic stress response. Tissue expression profiling analysis revealed that NgCHS2 and NgCHS7 were highly expressed in young leaves,which is consis-tent with the results of phylogenetic analysis. Enzyme activity assay demonstrated that NgCHS7 catalyzes the condensa-tion of p-coumaroyl-CoA and malonyl-CoA to produce naringenin chalcone,exhibiting typical chalcone synthase activity. This study systematically reveals,for the first time,the member composition,evolutionary characteristics,and enzy-matic function of the CHS gene family in N.grossedentata.These findings provide key genetic resources and a theoretical basis for deciphering the regulatory mechanisms of flavonoid metabolism and for the molecular breeding of high-flavonoid vine tea.