Regulation of gibberellin biosynthesis by light

Abstract

Phytochromes regulate transcript levels of gibberellin biosynthesis enzymes, GA 20-oxidases and/or GA 3beta-hydroxylases, in germinating lettuce and Arabidopsis seeds and in de-etiolating pea seedlings. Feedback regulation of GA biosynthesis by active GA is well established, but other mechanisms for regulation of these biosynthetic genes also exist, as this feedback does not operate on a GA 3beta-hydroxylase gene of Arabidopsis during seed germination.