SIAMESE-RELATED1 Is Regulated Posttranslationally and Participates in Repression of Leaf Growth under Moderate Drought

Plant Physiology
Marieke DuboisP Genschik

Abstract

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 SIAMESE-RELATED1 (SMR1) is quickly induced under moderate drought in young Arabidopsis (Arabidopsis thaliana) 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 SMR1 transcript and SMR...Continue Reading

Citations

Jan 23, 2020·Journal of Experimental Botany·Marieke Dubois, Dirk Inzé
Nov 9, 2018·Frontiers in Genetics·Michael André FritzAdrien Sicard
Mar 11, 2021·Annual Review of Plant Biology·Akie ShimotohnoMasaaki Umeda
Oct 26, 2021·The Plant Journal : for Cell and Molecular Biology·Rubén Tenorio BerríoMarieke Dubois
Dec 9, 2020·Developmental Cell·Heng ZhangJian-Kang Zhu
Dec 5, 2021·The Plant Journal : for Cell and Molecular Biology·Takashi KuromoriKazuo Shinozaki

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