糖基转移酶CsUGT73B4和CsUGT85K5在茶树响应低温胁迫中的分子机制OA

INTRODUCTION:Glycosyltransferases are key enzymes involved in various biological processes in plants.To date,glycosyltransferases have been classified into 138 families,among which the glycosyltransferase family Ⅰ is the largest.This family primarily uses UDP-glucose as the glycosyl donor and is referred to as the UGT family.In recent years,the role of UGT genes in plant responses to abiotic stresses has gradually been revealed.However,currently,only a few UGT genes have been clearly identified as being involved in anthocyanin biosynthesis. RATIONALE:To explore the mechanisms of anthocyanin and its glycosylation-related genes in tea plants under low-temperature stress,this study used FudingDabai Tea as the experimental material.Based on the transcriptome se-quencing data,two genes,CsUGT73B4(CSS0039619)and CsUGT85K5(CSS0047548),which significantly upregulate anthocyanin expression,were identified.We further investigated the changes of gene expression and explored their rela-tionship with anthocyanin metabolism under low-temperature stress.Additionally,the functions of these two genes were verified through heterologous overexpression in Arabidopsis thaliana and gene silencing experiments. RESULTS:Under low-temperature stress,the expression of CsUGT73B4 and CsUGT85K5 genes was positively corre-lated with anthocyanin accumulation.In Arabidopsis thaliana plants overexpressing these genes,anthocyanin content and antioxidant enzyme activities(SOD,POD,and CAT)were significantly increased,while malondialdehyde(MDA)content and relative electrical conductivity were reduced.After transient silencing of CsUGT73B4 or CsUGT85K5 in tea plants,the anthocyanin content and the expression levels of its biosynthesis-related genes were significantly down-reg-ulated. CONCLUSION:In summary,the CsUGT73B4 and CsUGT85K5 genes are involved in the response to low-temperature stress,regulate anthocyanin metabolism,and may enhance the cold tolerance of tea plants.