Ubeda-Tomas S, Swarup R, Coates J, Swarup K, Laplaze L, Beemster GTS, Hedden P, Bhalerao R, Bennett MJ
Root growth in Arabidopsis requires gibberellin/DELLA signalling in the endodermis
Nature Cell Biology: 2008 10:625-628
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.
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