SCF(SAP) controls organ size by targeting PPD proteins for degradation in Arabidopsis thaliana.

Zhibiao Wang,Na Li,Yunhai Li,Shan Jiang,Nathalie Gonzalez,Yingchun Wang,Dirk Inzé,Xiahe Huang

doi:10.1038/ncomms11192

Abstract

Control of organ size by cell proliferation and growth is a fundamental process, but the mechanisms that determine the final size of organs are largely elusive in plants. We have previously revealed that the ubiquitin receptor DA1 regulates organ size by repressing cell proliferation in Arabidopsis. Here we report that a mutant allele of STERILE APETALA (SAP) suppresses the da1-1 mutant phenotype. We show that SAP is an F-box protein that forms part of a SKP1/Cullin/F-box E3 ubiquitin ligase complex and controls organ size by promoting the proliferation of meristemoid cells. Genetic analyses suggest that SAP may act in the same pathway with PEAPOD1 and PEAPOD2, which are negative regulators of meristemoid proliferation, to control organ size, but does so independently of DA1. Further results reveal that SAP physically associates with PEAPOD1 and PEAPOD2, and targets them for degradation. These findings define a molecular mechanism by which SAP and PEAPOD control organ size.

Highlights

Control of organ size by cell proliferation and growth is a fundamental process, but the mechanisms that determine the final size of organs are largely elusive in plants
Plant organ growth is determined by both cell proliferation and cell expansion that partially overlap in time; these processes are suggested to be coordinated[10]
AINTEGUMENTA, AUXIN-REGULATED GENE INVOLVED IN ORGAN SIZE (ARGOS), GROWTH-REGULATING FACTORS (AtGRFs), GRF-INTERACTING FACTORS (AtGIFs) and KLUH/CYP78A5 promote organ growth by increasing cell proliferation[7,13,14,15,16,17,18,19]

Summary

Introduction

Control of organ size by cell proliferation and growth is a fundamental process, but the mechanisms that determine the final size of organs are largely elusive in plants. We show that the F-box protein SAP acts as part of the SCF complex and controls organ size by promoting the proliferation of meristemoid cells.

Results

Conclusion