|Authors: ||H. Lin, S. Wang, T. Saito, H. Ohara, K. Okawa, H. Jia, Y. Gou, S. Kondo|
|Keywords: ||abscisic acid, abscinazole-E3, ethephon, grape, maturation|
There is evidence that abscisic acid (ABA) and ethylene both play important roles in the physiological processes of grape maturation.
However, the interaction between ABA and ethylene metabolism in grape maturation is unclear.
We applied 50 μM (±) abscinazole-E3 (Abz, ABA 8'-hydroxylase inhibitor) or 500 μM ethephon to grape berries at 44 DAFB (days after full bloom). Grape berries were sampled at 44, 48, 54, 64, 94 DAFB. The ABA, ethylene concentrations and related gene expressions were analyzed.
The results showed that Abz or ethephon treatment decreased the firmness and titratable acid concentration.
Abz treatment inhibited VvCYP707A1 gene expression levels at 48 DAFB and increased endogenous ABA accumulation at 54 DAFB. Ethephon treatment significantly up-regulated VvNCED1 gene expression levels at 48 DAFB and VvCYP707A1 at 54 DAFB, but had no effect on ABA concentration.
Ethylene and gene expression levels of VvACO1 and VvERF2 in Abz- and ethephon-treated berries at 48 DAFB were up-regulated.
Abz or ethephon treatment also accelerated chlorophyll breakdown in berry skin with the up-regulation of VvPPH and VvRCCR gene expression levels.
The total sugar concentrations slightly increased in both Abz- and ethephon-treated berries.
These results suggest that Abz treatment before veraison can stimulate grape maturation by increasing endogenous ABA and the ethephon treatment can promote grape maturation similarly to Abz, through VvACO1 and VvERF2.
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