六出花链格孢中杨梅素合成关键基因的鉴定与功能分析OA

Myricetin(M),a flavonol compound,exhibits activities in antioxidant,anti-inflammatory,and anti-tumor properties.However,the complete fungal-derived biosynthetic pathway of myricetin remains unclear.In this investigation,Alternaria alstroemeria ZZ-HY-03-02 was used as the research material,and three key genes involved in myricetin biosynthesis,AaCHI(gene encoding chalcone isomerase),AaF3′5′H(gene encoding flavonoid 3′,5′-hydroxylase),and AaFLS(gene encoding flavonol synthase),were identified.Heterologous expression of these three genes in Aspergillus nidulans LO8030 showed that all of them could exert activity in the heterologous host and activate the biosynthesis of myricetin,with the AN-AaFLS strain achieving a myricetin yield of(12.94±0.35)μg/L.Feeding experiments revealed that AaFLS targetedly catalyzed the synthesis of myricetin from dihydromyricetin(DHM),and AaCHI could catalyze the isomerization of naringenin chalcone(Nar-chalcone)into naringenin(Nar).However,unlike conventional myricetin biosynthetic pathway,AaF3′5′H may have a unique catalytic pathway.Metabolomic analysis indicated that these three genes could influence the content of final metabolites by mediating multiple upstream metabolic pathways such as tryptophan metabolism and tyrosine metabolism.Through gene mining and heterologous expression technology,this study clarified the functions of key genes in myricetin biosynthesis in A.alstroemeria,providing a theoretical basis and key biosynthetic technical support for myricetin biosynthesis in fungi.