A mutation in the expansin-like A2 gene enhances resistance to necrotrophic fungi and hypersensitivity to abiotic stress in Arabidopsis thaliana
A mutation in the expansin-like A2 gene enhances resistance to necrotrophic fungi and hypersensitivity to abiotic stress in Arabidopsis thaliana
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DOI：
10.1111/mpp.12049
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发表时间：
2013-10-01
影响因子：
4.9
通讯作者：
Iratni, Rabah
中科院分区：
文献类型：
--
作者：
Abuqamar, Synan;Ajeb, Suad;Iratni, Rabah
膨胀素是细胞壁疏松剂，已知其在细胞壁延展性中的内源性功能。拟南芥扩展蛋白样A2（EXLA 2）基因通过其响应于坏死营养型病原体灰葡萄孢（Botrytis cinerea）的感染的下调以及通过exla 2突变体对相同病原体的降低的易感性来鉴定。exla 2突变体同样对假单胞菌pv.番茄，但更耐坏死营养型真菌芸苔链格孢，当与野生型或与转基因，异位EXLA 2过表达线。exla 2突变体还增强了对植物前列烷-A的耐受性（1）。这表明EXLA 2的缺失或下调导致对B.cinerea的抗性以COI 1依赖性方式增加，并且这种下调可以通过植物前列烷-A（1）处理实现。EXLA 2被盐和冷显著诱导，并且通过外源施用脱落酸诱导。exla 2突变体也表现出对增加的盐和冷的超敏反应，这种超敏反应需要功能性脱落酸途径。EXLA 2的差异时间表达和具有改变的EXLA 2表达的转基因植物中的表型表明植物细胞壁结构在拟南芥发育阶段中是重要的参与者。我们的研究结果表明，EXLA 2似乎是重要的，在响应各种生物和非生物胁迫，特别是在坏死型病原体的发病机制和非生物胁迫的耐受性。
Expansins are cell wall loosening agents, known for their endogenous function in cell wall extensibility. The Arabidopsis expansin-like A2 (EXLA2) gene was identified by its down-regulation in response to infection by the necrotrophic pathogen Botrytis cinerea, and by the reduced susceptibility of an exla2 mutant to the same pathogen. The exla2 mutant was equally susceptible to Pseudomonas syringae pv. tomato, but was more resistant to the necrotrophic fungus Alternaria brassicicola, when compared with the wild-type or with transgenic, ectopic EXLA2-overexpressing lines. The exla2 mutants also enhanced tolerance to the phytoprostane-A(1). This suggests that the absence or down-regulation of EXLA2 leads to increased resistance to B.cinerea in a CORONATINE INSENSITIVE 1 (COI1)-dependent manner, and this down-regulation can be achieved by phytoprostane-A(1) treatment. EXLA2 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 EXLA2 and the phenotypes in transgenic plants with altered expression of EXLA2 indicate that plant cell wall structure is an important player during Arabidopsis developmental stages. Our results indicate that EXLA2 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.