Integrated transcriptomic and metabolic analyses unveil anthocyanins biosynthesis metabolism in three different color cultivars of grape (Vitis vinifera L.)

Anthocyanins as plant pigments are responsible for the color of the grape berry. The major concern among consumers is color, quality, and appearance, therefore, skin color is the most important item that affects consumer purchases. In this study, we used three grape cultivars namely Red globe (bright red), Kyoho (purple-red), and Wink (purple-black), and evaluated color changes in three different developmental stages according to time course including 15 days after the berry color shift from green to red (V1), 25 days after the berry color shift from green to red (V2), and 35 days after the berry color shift from green to red (V3). The dynamic changes in anthocyanin content and components were detected using "High-Performance Liquid Chromatography mass spectrometry/mass spectrometry (HPLC-MS/MS)" technology. Furthermore, we performed transcriptome sequencing and identified the genes involved in the anthocyanin biosynthesis and accumulation in grape berry development. In total, we detected 13 different anthocyanin components in three grape cultivars. Malvidin, petunidin, and delphinidin derivates are the main components of dark colored grape (Kyoho and Wink), while cyanidin and pelargonidin derivates are the sources of bright-colored grape (Red globe). According to Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, many DEGs were enrichment in phenylpropanoid biosynthesis and flavonoid biosynthesis. We also found thirty-nine DEGs to be involved in the anthocyanin metabolism and accumulation. Furthermore, using weighted gene correlation analysis (WGCNA), three modules (blue, magenta, and tan) and nineteen hub genes were highly correlated with anthocyanin variation. Our research provided new insights for elucidating the anthocyanin metabolic pathway and related genes, signal perception and transduction during grape berries development at different stages.