Abstract
The accumulation of abscisic acid (ABA) is considered a crucial signal for the onset of berry maturation in grape berry, including ‘Kyoho’ (Vitis labruscana L.). Therefore, the delay of grape berry maturation, especially of peel coloration, by applying an ABA inhibitor (nordihydroguaiaretic acid, NDGA) to berry clusters has been investigated in various studies. Herein, we report for the first time that NDGA treatment on leaves inhibited the accumulation of both ABA, and genes related to ABA signal transduction, in berry peels and triggered the inhibition of anthocyanin and the accumulation of sucrose. We also found that changes in the expression patterns of genes related to anthocyanin and sucrose biosynthesis were concomitant with changes in anthocyanin and sucrose accumulation. Finally, RNA sequence analysis showed that NDGA treatment on leaves changed the expression of genes related to internal oxygen levels in berry flesh, which is known to affect cellular alcohol dehydrogenase activity. In this study, we measured changes in the concentrations of alcoholic and alcohol-derived aroma volatiles such as hexenal and phenylethyl alcohol, and found that NDGA treatment on leaves inhibited the maturation of berry peel and flesh. These results suggest the possibility of ABA signal transduction from leaves to berries.
