English

Abstract

Procyanidins (PAs) is the important flavonoids components in strawberry young fruits, whichis synthesizedthrough direct polymerizationof flavanone-3-ol units. Numerous studies have beendone on the synthesis of PAs, while the oxidation/polymerization processes have not been fully explored. AtTT10, a laccasel-like polyphenol oxidase,was recently reported to be participated in the oxidative polymerization of proanthocyanidins. Whether FaTT10hasapositiveeffect onoxidative polymerization of strawberry fruit PAsis unclear. In this study, FaTT10 in strawberries were isolated and analyzed. Transient overexpression of FaTT10 decreased the accumulation of PAs monomer in strawberry fruit,whereas RNA interference increased the level of anthocyanin and PAs monomer. 4-Dimethylaminocinamaldehyde (DMACA)staining results also showed that lighter blue color in the FaTT10-RNAi fruit and concentrated blue color in the FaTT10-overexpression fruit. Meanwhile, PAs monomer showed a drop-and-rise tendency during strawberry fruit development and ripening.Furthermore, the expression of several flavonoids metabolism-related geneswere affected by the altered FaTT10 gene expression levels, such as L-phenylalanine ammonia-lyase(PAL); dihydroflavonol reductase(DFR);chalcone isomerase(CHI); flavanone 3-hydroxylase(F3H); 4-coumarate:CoA ligase(4CL); Cinnamate 4-hydroxylase(C4H); chalcone synthase(CHS); anthocyanin reductase(ANR); lecoanthocyanidins reductase(LAR) andanthocyanin synthase(ANS). In conclusion, these results revealed that FaTT10 is specifically involved in oxidative polymerization of PAsby regulating the expression of flavonoids metabolism-related genes in strawberry fruits. © 2021 Friends Science Publishers