Transcriptome and metabolite profiling reveal that spraying calcium fertilizer reduces grape berry cracking by modulating the flavonoid biosynthetic metabolic pathway

Grape (Vitis vinifera L.) is one of the most widely cultivated fruit crops globally. Fruit cracking during fruit growth and development severely affects yield and quality, resulting in significant economic losses. Currently, calcium fertilizer application is used to prevent berry cracking. However, the mechanisms by which calcium fertilizer treatment reduces berry cracking are poorly understood. To explore this, transcriptomics and metabolomics were used to identify the differentially expressed genes (DEGs) and differentially abundant metabolites in V. vinifera ‘90-1’. We found that secondary metabolic pathways were enriched during the veraison and maturity stages, including the flavonoid biosynthesis pathway. Enrichment analysis indicated that most of the DEGs were enriched in the functional category of flavonoid biosynthesis. As secondary metabolites are largely antioxidants, the spraying of calcium fertilizers may improve the antioxidant capacity of the berries by regulating genes related to the flavonoid metabolism pathway, thus reducing the occurrence of berry cracking.