TITLE:
Effects of Abscisic Acid Treatment on Berry Coloration and Expression of Flavonoid Biosynthesis Genes in Grape
AUTHORS:
Ayako Katayama-Ikegami, Tomoaki Sakamoto, Kana Shibuya, Takane Katayama, Mei Gao-Takai
KEYWORDS:
Abscisic Acid (ABA), Anthocyanin, Biosynthetic Enzyme, Gene Expression, Transcription Factor
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.7 No.9,
July
18,
2016
ABSTRACT: In order to enhance berry coloration of bright-red grape cultivars, the
effects of abscisic acid (ABA) treatment on the quantity and composition of
anthocyanins as well as the expression of genes related to flavonoid
biosynthesis in the berry were examined.
Exogenous ABA treatment increased
anthocyanin content, especially petunidin- and malvidin-type anthocyanins. Quantitative
real-time PCR analysis revealed that ABA treatment around véraison
resulted in the upregulation of genes encoding enzymes responsible for both general
flavonoid and anthocyanin biosynthesis. On the other hand, the gene expressions
of enzymes involved in proanthocyanidin synthesis were drastically decreased at
véraison and remained extremely low even with ABA treatment. Thus, increases in
the total amount and composition ratios of petunidin- and malvidin-type anthocyanins
were mainly caused by ABA-induced upregulation of uridine diphosphate glucose flavonoid glucosyl transferase, glutathione S-transferase 4, O-methyl transferase and flavonoid 3’, 5’ hydroxylase expression,
resulting in the deep coloration of berry of skin.