Root growth in Arabidopsis requires gibberellin/DELLA signalling in the endodermis

Susana Úbeda-Tomás, Ranjan Swarup, Juliet Coates, Kamal Swarup, Laurent Laplaze, Gerrit T.S. Beemster, Peter Hedden, Rishikesh Bhalerao & Malcolm J. Bennett

Gibberellins (GAs) are key regulators of plant growth and development. They promote growth by targeting the degradation of DELLA repressor proteins; however, their site of action at the cellular, tissue or organ levels remains unknown. To map the site of GA action in regulating root growth, we expressed gai, a non-degradable, mutant DELLA protein, in selected root tissues. Root growth was retarded specifically when gai was expressed in endodermal cells. Our results demonstrate that the endodermis represents the primary GA-responsive tissue regulating organ growth and that endodermal cell expansion is rate-limiting for elongation of other tissues and therefore of the root as a whole.

Nature Cell Biology 10 (5), 625-628

Read the Full Text at the publishers site
(may require institutional login)