Transcriptomic and metabolomic analysis provides insights into anthocyanin and pyocyanin accumulation in pear

Abstract

BackgroundPear is one of the most important fruit crops worldwide. Anthocyanins and procyanidins (PAs) are important secondary metabolic substances that affect the appearance and nutritive quality of pear. However, few studies have focused on the molecular mechanism underlying anthocyanin and PA accumulation in pear.ResultsWe conducted metabolome and transcriptome analyses to identify candidate genes involved in anthocyanin and PA accumulation in young pear fruits of ‘Clapp Favorite’ (CF) and its red mutation variety ‘Red Clapp Favorite’ (RCF). Gene–metabolite correlation analyses revealed a core set of 20 genes for pear anthocyanin and PA accumulation. One gene in the core set, PcGSTF12, was confirmed to be involved in anthocyanin and PA accumulation by complementation of the tt19-7 Arabidopsis mutant. Interestingly, PcGSTF12 was found to be responsible for procyanidin A3 accumulation, but not petunidin 3, 5-diglucoside accumulation, opposite to the function of AtGSTs in Arabidopsis. Transformation with PcGSTF12 greatly promoted or repressed genes involved in anthocyanin and PA biosynthesis, regulation, and transport. Electrophoretic mobility shift and luciferase reporter assays confirmed positive regulation of PcGSTF12 by PcMYB114.ConclusionThese findings identify a core set of genes for pear anthocyanin and PA accumulation. Of these, PcGSTF12, was confirmed to be involved in anthocyanin and PA accumulation. Furthermore, an important anthocyanin and PA regulation node was constructed by two core genes, PcGSTF12 and PcMYB114. These results provide novel insights into anthocyanin and PA accumulation in pear and represent a valuable data set to guide future functional studies and pear breeding.