López-Cruz Jaime, Finiti Ivan, Fernández-Crespo Emma, Crespo-Salvador Oscar, García-Agustín Pilar, González-Bosch Carmen
Departamento de Bioquímica y Biología Molecular, Universidad de Valencia, IATA (CSIC), Avda Agustín Escardino 7, 46980 Paterna, Valencia, Spain.
Laboratorio de Bioquímica y Biotecnología, Área de Fisiología Vegetal, Departamento de Ciencias Agrarias y del Medio Natural, ESTCE, Universitat Jaume I, 12071 Castellón, Spain.
J Plant Physiol. 2014 Oct 15;171(16):1524-32. doi: 10.1016/j.jplph.2014.07.006. Epub 2014 Jul 23.
During plant-pathogen interactions, the plant cell wall forms part of active defence against invaders. In recent years, cell wall-editing enzymes, associated with growth and development, have been related to plant susceptibility or resistance. Our previous work identified a role for several tomato and Arabidopsis endo-1,4-β-glucanases (EGs) in plant-pathogen interactions. Here we studied the response of the Arabidopsis thaliana T-DNA insertion mutant lacking EG Korrigan1 (KOR1) infected with Pseudomonas syringae. KOR1 is predicted to be an EG which is thought to participate in cellulose biosynthesis. We found that kor1-1 plants were more susceptible to P. syringae, and displayed severe disease symptoms and enhanced bacterial growth if compared to Wassilewskija (Ws) wild-type plants. Hormonal and gene expression analyses revealed that the jasmonic acid (JA) pathway was activated more in kor1-1 plants with an increase in the JA-biosynthesis gene LOX3 and a greater accumulation of JA. Upon infection the accumulation of JA and JA-isoleucine (JA-Ile) was higher than in wild-type plants and increased the induction of LOX3 and the JA-responsive PDF1.2 gene. In addition, the increase of salicylic acid (SA) in healthy and infected kor1-1 may reflect the complex interaction between JA and SA, which results in the more susceptible phenotype displayed by the infected mutant plants. Callose deposition was enhanced in infected kor1-1 and an increase in pathogen-induced hydrogen peroxide took place. The susceptible phenotype displayed by KOR1-deficient plants was coronatine-independent. No significant changes were detected in the hormonal profile of the kor1-1 plants infected by coronatine-deficient P. syringae cmaA, which supports that absence of EG KOR1 alters per se the plant response to infection. We previously reported increased resistance of kor1-1 to B. cinerea, hence, the lack of this EG alters cell wall properties and plant responses in such a way that benefits P. syringae colonisation but restricts B. cinerea invasion.
在植物与病原体的相互作用中，植物细胞壁是抵御入侵者的主动防御的一部分。近年来，与生长和发育相关的细胞壁编辑酶已与植物的易感性或抗性相关联。我们之前的工作确定了几种番茄和拟南芥内切-1,4-β-葡聚糖酶（EGs）在植物与病原体相互作用中的作用。在这里，我们研究了拟南芥T-DNA插入突变体缺乏EG Korrigan1（KOR1）被丁香假单胞菌感染后的反应。KOR1被预测为一种EG，被认为参与纤维素生物合成。我们发现，与Wassilewskija（Ws）野生型植物相比，kor1-1植物对丁香假单胞菌更敏感，表现出严重的病害症状且细菌生长增强。激素和基因表达分析表明，茉莉酸（JA）途径在kor1-1植物中被更强烈地激活，JA生物合成基因LOX3增加，JA积累更多。感染后，JA和茉莉酸异亮氨酸（JA-Ile）的积累高于野生型植物，并增加了LOX3和JA响应基因PDF1.2的诱导。此外，健康和感染的kor1-1中水杨酸（SA）的增加可能反映了JA和SA之间的复杂相互作用，这导致感染的突变植物表现出更易感性的表型。感染的kor1-1中胼胝质沉积增强，病原体诱导的过氧化氢增加。缺乏KOR1的植物表现出的易感性表型与冠菌素无关。用缺乏冠菌素的丁香假单胞菌cmaA感染kor1-1植物后，其激素谱没有显著变化，这支持了缺乏EG KOR1本身会改变植物对感染的反应。我们之前报道过kor1-1对灰霉病菌的抗性增加，因此，这种EG的缺失以有利于丁香假单胞菌定殖但限制灰霉病菌入侵的方式改变了细胞壁特性和植物反应。
