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Regulation of Gibberellin 20-Oxidase and Gibberellin 3ß-Hydroxylase Transcript Accumulation during De-Etiolation of Pea Seedlings

journal contribution
posted on 2023-05-16, 11:58 authored by Ait-Ali, T, Frances, F, James WellerJames Weller, James ReidJames Reid, Kendrick, RE, Kamiya, Y
Gibberellin (GA) 20-oxidase (GA 20-ox) and GA 3β-hydroxylase (GA 3β-hy) are enzymes that catalyze the late steps in the formation of active GAs, and are potential control points in the regulation of GA biosynthesis by light. We have investigated the photoregulation of the GA 20-ox and GA 3β-hy transcript levels in pea (Pisum sativum L.). The GA 20-ox transcript level was higher in light-grown seedlings than in etiolated seedlings, whereas GA 3β-hy mRNA accumulation was higher in etiolated seedlings. However, transfer of etiolated seedlings to light led to a 5-fold increase in the expression of both transcripts 4 h after transfer. GA 20-ox mRNA accumulation is regulated by both phytochromes A and B. Transfer to light also resulted in a 6-fold decrease in GA1 levels within 2 h. These results suggest that the light-induced drop in GA1 level is not achieved through regulation of GA 20-ox and GA 3β-hy mRNA accumulation. The application of exogenous GA1 to apical buds of etiolated seedlings prior to light treatments inhibited the light-induced accumulation of both GA 20-ox and GA 3β-hy mRNA, suggesting that negative feedback regulation is an important mechanism in the regulation of GA 20-ox and GA 3β-hy mRNA accumulation during de-etiolation of pea seedlings.

History

Publication title

Plant Physiology

Volume

121

Pagination

783-791

ISSN

0032-0889

Department/School

School of Natural Sciences

Publisher

American Society of Plant Physiologists

Place of publication

Rockville, USA

Repository Status

  • Restricted

Socio-economic Objectives

Horticultural crops not elsewhere classified

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