| Pear is one of the most important fruit crops worldwide.Anthocyanins and procyanidins are important material components with red skin and important secondary metabolites of nutrient quality.With the rise of red-skin pear breeding at home and abroad in recent years,research on the regulation of anthocyanins and procyanidins has attracted widespread attention.So far,however,the molecular mechanisms are still not clear.To this end,this study explored the key genes for the regulation of synthesis of pyanidin and proanthocyanin by integrating transcriptomics and metabolomics,and further selected core genes for functional verification on this basis,so as to analyze the regulatory relationship between these core genes.The results provided a useful reference for future studies on the synthesis and regulation of anthocyanins and proanthocyanidins of Pear and breeding of red-skin pear.The main research contents and results are shown as follows:1.In total,4065 differentially expressed genes(DEGs),and 19 differentially expressed metabolites(12 anthocyanins and 7 PAs)were identified between ‘CF’ and ‘RCF’ at early developmental stages and/or between two stages within ‘CF’ and /or ‘RCF’.2.Correlation analyses between DEGs and anthocyanins/PAs revealed 364 strong correlations between 12 anthocyanins,7 PAs,and 266 genes in the categories of DNA binding,plant hormone signal transduction,flavonoid biosynthesis,phenylpropanoid biosynthesis,brassinosteroid biosynthesis,zeatin biosynthesis,flavonoid metabolism,phenylalanine metabolism,glutathione metabolism,and ABC transporters.3.We constructed connection networks of anthocyanins,PAs,and genes,which revealed details of the regulatory system involved in anthocyanins and PAs accumulation in ‘CF’ and ‘RCF’.In this study,a new MYB transcription factor gene named PcMYB114 was isolated from pear fruit.EMSA assay demonstrated that PcMYB114 bind to the promoter of PcGSTF12 gene and LUC activity experiments showed that PcMYB114 can promote the activity of the PcGSTF12 gene promoter,respectively,which leads to anthocyanins and proanthocyanins accumulationin transgenic callus.Our results show that PcMYB114 is the key component responsible for the red mutation.4.To characterize the function of PcGSTF12 in planta,we constracted 35S::PcGSTF12 construct,and then transformed it into Arabidopsis(tt19-7).Ectopic expression of PcGSTF12 effectively restored the lack of anthocyanins in Arabidopsis thaliana(tt19-7)seedlings,especially under continuous light conditions,and the species of anthocyanins and proanthocyanidins in transgenic Arabidopsis increased significantly.These results indicated that PcGSTF12 involved inanthocyanins accumulation in planta. |
