Effects of Abscisic Acid on Capsanthin Levels in Pepper Fruit

摘要

Abscisic acid (ABA) is an important plant hormone that plays an important role in stress responses. Previous studies have suggested that ABA can also accelerate ripening in climacteric and nonclimacteric fruit. Capsanthin is a carotenoid that confers red coloration to mature pepper (Capsicum annuum) fruit. However, the effect of ABA on capsanthin accumulation in pepper fruit has not been thoroughly studied. Herein, we aimed to evaluate the effects of ABA treatment on capsanthin accumulation in pepper fruit and on the expression of key genes involved in the capsanthin biosynthetic pathway. For this purpose, we treated pepper fruit with ABA at green mature stage. Our results indicate that ABA treatment increased capsanthin content in pepper fruit, with the best result obtained with 150 mg.L-1 ABA solution. Application of exogenous ABA also increased the expression levels of the capsanthin synthesis genes phytoene synthase (Psy), lycopene beta-cyclase (Lcyb), beta-carotene hydroxylase (Crtz), and capsanthin/capsorubin synthase (Ccs), likely explaining the significant capsanthin content increase in pepper fruit.