Constitutive Expresser of Pathogenesis Related Genes 1 Is Required for Pavement Cell Morphogenesis in Arabidopsis.

Bing Han,Jing Wang,Liang Chen,Longfeng Yan,Zhongliang Wu,Suiwen Hou,Shao Jun Dai

doi:10.1371/journal.pone.0133249

Abstract

For over 50 years, researchers have focused on the mechanisms underlying the important roles of the cytoskeleton in controlling the cell growth direction and cell expansion. In our study, we performed ethyl methane sulfonate mutagenesis on Col-0 background and identified two new CONSTITUTIVE EXPRESSER OF PATHOGENESIS RELATED GENES 1 (CPR1) alleles with pavement cell (PC) morphogenetic defects. Morphological characterizations showed that polar growth initiation and expansion of PCs are seriously suppressed in cpr1. Closer cytoskeleton investigation showed that the directional arrangement of microtubules (MTs) during PC development is defective and the cortical fine actin filaments cannot be aggregated effectively to form actin cable networks in cpr1 mutants. These results suggest that the abnormal PC morphogenesis in cpr1 is accompanying with the aberrant arrangement of cytoskeleton. Site-directed mutagenesis and knockout within the F-box-associated (FBA) domain, which is reported to be a motif for recognizing particular substrates of CPR1, proved that the FBA domain is indispensable for normal CPR1 regulation of the PC morphogenesis. Further genetic analysis indicated that the defects on PC morphogenesis of cpr1 depend on two lipase-like proteins, ENHANCED DISEASE SUSCEPTIBILITY 1 and PHYTOALEXIN DEFICIENT 4. Our results provide further insights into the relationship between the cytoskeleton and PC morphogenesis, and suggest that the cytoskeleton-mediated PC morphogenesis control might be tightly linked to plant defense responses.

Highlights

Cell shape formation and regulation are crucial for cell function, tissue and organ development, and morphogenesis in plant [1,2,3]
Our results suggest that CONSTITUTIVE EXPRESSER OF PATHOGENESIS RELATED GENES 1 (CPR1)-regulated cytoskeleton arrangement controls pavement cell (PC) morphogenesis, which is involved in the natural plant defense responses, and that the FBA domain is indispensable for normal CPR1 function
The abnormal PC shapes of cpr1-j594 and cpr1-j2928 were rescued at 28°C (Fig 10K and 10L; Fig 11), indicating that high temperature can rescue the phenotype of PCs in cpr1 mutants. These results suggest that the CPR1-controlled PC morphogenesis requires normal PHYTOALEXIN DEFICIENT 4 (PAD4) and ENHANCED DISEASE SUSCEPTIBILITY 1 (EDS1), and is temperature dependent

Summary

Introduction

Cell shape formation and regulation are crucial for cell function, tissue and organ development, and morphogenesis in plant [1,2,3]. The control mechanisms of the cell shape have attracted great interest. Leaf epidermal pavement cell (PC) with a multi-polar growth pattern exhibits complex cell shape and serves as an exciting model to investigate the mechanisms of cell shape formation [4,5,6,7]. By studying mutants with impaired PC morphogenesis, researchers have. CPR1 Is Required for Pavement Cell Morphogenesis in Arabidopsis

Methods

Discussion

Conclusion