FaTT12-1, a multidrug and toxin extrusion (MATE) member involved in proanthocyanidin transport in strawberry fruits

Proanthocyanidin and anthocyanin comprise the most important phenolic components in strawberry fruits. Biosynthesis of these products has been extensively studied, but the transportation and trafficking processes are far from clear. Members of multidrug and toxin extrusion (MATE) transporters are imparted in the secondary metabolites transportation. In this study, we identified 53 MATE family members in the diploid Fragaria vesca genome. Based on homologous strategies, we obtained a potential AtTT12 orthologue in the octoploid strawberry, nominated as FaTT12-1. It could be detected in both vegetative and reproductive organs, but mainly in young tissues including young leaves and green fruits. Diverse cis-regulatory elements were recognized in the FaTT12-1 promoter. Blue light irradiation and abscisic acid treatment did not impact the expression of FaTT12-1. But red light irradiation can significantly elevate the transcription. Perturbation of FaTT12-1 via virus induced gene silencing (VIGS) in strawberry fruits did not give obvious visual changes. Fruit anthocyanin remained but proanthocyanidins were affected. In conclusion, we provide evidences that FaTT12-1 is a member of MATE family, specifically involved in proanthocyanidin accumulation in strawberry fruits.