Open AccessA mutation in the expansin‐like A 2 gene enhances resistance to necrotrophic fungi and hypersensitivity to abiotic stress in A rabidopsis thaliana
Author(s) -
Abuqamar Synan,
Ajeb Suad,
Sham Arjun,
Enan Mohamed Rizq,
Iratni Rabah
Publication year - 2013
Publication title -
molecular plant pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.945
H-Index - 103
eISSN - 1364-3703
pISSN - 1464-6722
DOI - 10.1111/mpp.12049
Subject(s) - biology , expansin , abscisic acid , pseudomonas syringae , botrytis cinerea , mutant , arabidopsis , microbiology and biotechnology , arabidopsis thaliana , biotic stress , abiotic stress , ectopic expression , botany , pathogen , gene , gene expression , genetics
Summary Expansins are cell wall loosening agents, known for their endogenous function in cell wall extensibility. The A rabidopsis e xpansin‐like A 2 ( EXLA 2 ) gene was identified by its down‐regulation in response to infection by the necrotrophic pathogen B otrytis cinerea , and by the reduced susceptibility of an exla2 mutant to the same pathogen. The exla2 mutant was equally susceptible to P seudomonas syringae pv. tomato , but was more resistant to the necrotrophic fungus A lternaria brassicicola , when compared with the wild‐type or with transgenic, ectopic EXLA 2 ‐overexpressing lines. The exla2 mutants also enhanced tolerance to the phytoprostane‐ A 1 . This suggests that the absence or down‐regulation of EXLA 2 leads to increased resistance to B . cinerea in a CORONATINE INSENSITIVE 1 ( COI 1)‐dependent manner, and this down‐regulation can be achieved by phytoprostane‐ A 1 treatment. EXLA 2 is induced significantly by salinity and cold, and by the exogenous application of abscisic acid. The exla2 mutant also showed hypersensitivity towards increased salt and cold, and this hypersensitivity required a functional abscisic acid pathway. The differential temporal expression of EXLA 2 and the phenotypes in transgenic plants with altered expression of EXLA 2 indicate that plant cell wall structure is an important player during A rabidopsis developmental stages. Our results indicate that EXLA 2 appears to be important in response to various biotic and abiotic stresses, particularly in the pathogenesis of necrotrophic pathogens and in the tolerance to abiotic stress.