Figure 8.

Stimulatory effect of kaolin on the transcription of genes involved in anthocyanin S-conjugation and vacuolar transport capacity. (A) Transcript levels of glutathione S-transferase 4 (VvGST4) and of anthocyanin tonoplast transporters MATE1 (VvMATE1) (B) and ABCC1 (C) in grape berries. Gene expression analyses were performed by real-time qPCR in grape berry tissues collected in four different maturation stages (green, véraison, mature, and full mature) from vines subjected to kaolin treatment and without application (control). VvGST4, VvMATE1, and VvABCC1 relative expression levels were obtained after normalization with the expression of the reference genes VvACT1 and VvGAPDH. Two independent PCR runs with triplicates were performed for each tested mRNA. Values are the mean ± SEM. Asterisks indicate statistical significance (Student's t-test; ^*P < 0.05; ^**P < 0.01).