In Vitro and in Situ Inhibition of Carotenoid Biosynthesis in Capsicum annuum by Bleaching Herbicides

Authors:
Publisher website
Google Scholar
Abstract
Pepper leaves treated with the herbicide J852 show an accumulation of phytoene and ζ-carotene, whereas treatment with norflurazon led to an accumulation of only phytoene. The effects of these herbicides were examined in vitro after the expression of carotenoid desaturases in Escherichia coli. Whereas norflurazon is a potent inhibitor of phytoene desaturase (PDS) (I50 = 0.12 μM) but not of ζ-carotene desaturase (ZDS) (I50 = 144 μM), J852 inhibits both PDS (I50 = 23 μM) and ZDS (I50 = 49 μM). The influence of PDS/ZDS inhibition on gene expression was examined by comparative RT-PCR. None of the examined genes, namely, encoding phytoene synthase, PDS, ZDS, or the terminal oxidase associated with phytoene desaturation, were induced upon herbicide treatment in pepper leaves or seedlings. This was unexpected because inhibition of carotene desaturation led to an up-regulation of the carotenoid biosynthetic capacity (higher amounts of accumulating precursors plus remaining colored carotenoids are present in treated tissues versus control). Keywords: ζ-Carotene desaturase; phytoene desaturase; phytoene synthase; plastid terminal oxidase; carotenogenic gene expression; norflurazon; J852; photo-oxidation; plastids; carotenoids; chlorophyll

This publication has 20 references indexed in Scilit: