Transcriptomics combined with metabolisms reveals the effect of light-exclusive films on the quality and polyphenols of ‘Cabernet Sauvignon’ grapes

The grape quality might be affected if the solar intensity (SI) was too strong. In this study, the influence of light-exclusive films on the transcriptomic properties and metabolic substances of grapes were evaluated. The results showed that films, especially polycarbonate (PC), could significantly decrease the SI. The sugar content was obviously decreased, while the acid content was increased. The anthocyanin content was decreased, in contrast to the total polyphenols, flavonoids and tannins. The corresponding derivatives owned the same trend. Lots of differentially expressed genes (DEGs) were detected, especially under PC. The expression pattern and GO function enrichment of DEGs from PC significantly differed from other groups. DEGs enrichment also proved that films, especially PC, could significantly improve the contents of tannins, flavonoids and other polyphenols. VvUFGT, VvF3′5′H, VvLDOX, VvLAR1 and VvANR were confirmed to be the key genes in the biosynthetic pathway of polyphenols under different films.