Autophagy differentially controls plant basal immunity to biotrophic and necrotrophic pathogens
Autophagy differentially controls plant basal immunity to biotrophic and necrotrophic pathogens
复制标题
DOI：
10.1111/j.1365-313x.2011.04546.x
复制
发表时间：
2011-06-01
期刊：
影响因子：
7.2
通讯作者：
Nuernberger, Thorsten
中科院分区：
文献类型：
--
作者：
Lenz, Heike D.;Haller, Eva;Nuernberger, Thorsten
在植物中，自噬在控制与微生物效应器引发的免疫相关的程序性细胞死亡方面被分配了“促死亡”和“促生存”的角色。然而，自噬在对强毒病原体的基础免疫中的作用还没有被系统地解决。利用几种自噬缺陷(ATG)基因，我们确定了自噬在植物基础免疫中的作用。缺乏ATG5、ATG10和ATG18a的拟南芥突变体在被坏死性病原菌油菜链格孢菌侵染时发生扩散性坏死，同时伴随着活性氧中间体的产生和菌丝生长的增强。同样，用真菌毒素伏马菌素B1治疗会导致ATG突变基因型的扩散性病变形成。我们认为，自噬构成了一种“有利于生存”的机制，控制着宿主组织破坏性微生物感染的遏制。相反，ATG植物没有表现出扩散性的坏死，但对强毒的生物营养型植物病原菌紫丁香假单胞菌表现出显著的抗性。番茄。在ATG基因中，与植物基础免疫相关的诱导防御系统，例如，胼胝质的产生或丝裂原活化蛋白激酶的激活，没有改变。然而，植物激素分析表明，非侵染和细菌侵染的ATG植株的水杨酸(SA)水平略高于Col-0植株，并伴随着SA依赖的基因表达和Camalexin产量的增加。这表明，以前未被检测到的适度感染诱导的SA上升导致可测量的细菌耐药性增强，而自噬负面控制SA依赖的防御和对细菌感染的基础免疫。我们推断，自噬促进植物对不同病原体免疫的方式在机制上是不同的，因此类似于这一过程在动物先天免疫中的复杂作用。
P>In plants, autophagy has been assigned 'pro-death' and 'pro-survival' roles in controlling programmed cell death associated with microbial effector-triggered immunity. The role of autophagy in basal immunity to virulent pathogens has not been addressed systematically, however. Using several autophagy-deficient (atg) genotypes, we determined the function of autophagy in basal plant immunity. Arabidopsis mutants lacking ATG5, ATG10 and ATG18a develop spreading necrosis upon infection with the necrotrophic fungal pathogen, Alternaria brassicicola, which is accompanied by the production of reactive oxygen intermediates and by enhanced hyphal growth. Likewise, treatment with the fungal toxin fumonisin B1 causes spreading lesion formation in atg mutant genotypes. We suggest that autophagy constitutes a 'pro-survival' mechanism that controls the containment of host tissue-destructive microbial infections. In contrast, atg plants do not show spreading necrosis, but exhibit marked resistance against the virulent biotrophic phytopathogen, Pseudomonas syringae pv. tomato. Inducible defenses associated with basal plant immunity, such as callose production or mitogen-activated protein kinase activation, were unaltered in atg genotypes. However, phytohormone analysis revealed that salicylic acid (SA) levels in non-infected and bacteria-infected atg plants were slightly higher than those in Col-0 plants, and were accompanied by elevated SA-dependent gene expression and camalexin production. This suggests that previously undetected moderate infection-induced rises in SA result in measurably enhanced bacterial resistance, and that autophagy negatively controls SA-dependent defenses and basal immunity to bacterial infection. We infer that the way in which autophagy contributes to plant immunity to different pathogens is mechanistically diverse, and thus resembles the complex role of this process in animal innate immunity.