SIAMESE-RELATED1 Is Regulated Posttranslationally and Participates in Repression of Leaf Growth under Moderate Drought.
Fiche publication
Date publication
avril 2018
Journal
Plant physiology
Auteurs
Membres identifiés du Cancéropôle Est :
Dr BAUMBERGER Nicolas
Tous les auteurs :
Dubois M, Selden K, Bediée A, Rolland G, Baumberger N, Noir S, Bach L, Lamy G, Granier C, Genschik P
Lien Pubmed
Résumé
The plant cell cycle is tightly regulated by factors that integrate endogenous cues and environmental signals to adapt plant growth to changing conditions. Under drought, cell division in young leaves is blocked by an active mechanism, reducing the evaporative surface and conserving energy resources. The molecular function of cyclin-dependent kinase-inhibitory proteins (CKIs) in regulating the cell cycle has already been well studied, but little is known about their involvement in cell cycle regulation under adverse growth conditions. In this study, we show that the transcript of the CKI gene () is quickly induced under moderate drought in young Arabidopsis () leaves. Functional characterization further revealed that SMR1 inhibits cell division and affects meristem activity, thereby restricting the growth of leaves and roots. Moreover, we demonstrate that SMR1 is a short-lived protein that is degraded by the 26S proteasome after being ubiquitinated by a Cullin-RING E3 ubiquitin ligase. Consequently, overexpression of a more stable variant of the SMR1 protein leads to a much stronger phenotype than overexpression of the native SMR1. Under moderate drought, both the transcript and SMR1 protein accumulate. Despite this induction, mutants do not show overall tolerance to drought stress but do show less growth inhibition of young leaves under drought. Surprisingly, the growth-repressive hormone ethylene promotes induction, but the classical drought hormone abscisic acid does not.
Mots clés
Arabidopsis, genetics, Arabidopsis Proteins, genetics, Cell Cycle, genetics, Droughts, Gene Expression Regulation, Developmental, Gene Expression Regulation, Plant, Meristem, genetics, Mutation, Nuclear Proteins, genetics, Phenotype, Plant Leaves, genetics, Plant Roots, genetics, Plants, Genetically Modified
Référence
Plant Physiol.. 2018 Apr;176(4):2834-2850