The Noble Research Institute, Ardmore, OK, USA.
Plant Sci. 2019 Feb;279:108-116. doi: 10.1016/j.plantsci.2018.07.002. Epub 2018 Jul 24.
Most potential pathogens fail to establish virulence for a plethora of plants found in nature. This intrinsic property to resist pathogen virulence displayed by organisms without triggering canonical resistance (R) genes has been termed nonhost resistance (NHR). While host resistance involves recognition of pathogen elicitors such as avirulence factors by bona fide R proteins, mechanism of NHR seems less obvious, often involving more than one gene. We can generally describe NHR in two steps: 1) pre-invasive resistance, either passive or active, which can restrict the pathogen from entering the host, and 2) post-invasive resistance, an active defense response that often results in hypersensitive response like programmed cell death and reactive oxygen species accumulation. While PAMP-triggered-immunity (PTI) is generally effective against nonhost pathogens, effector-triggered-immunity (ETI) can be effective against both host and nonhost pathogens. Prolonged interactions between adapted pathogens and their resistant host plants results in co-evolution, which can lead to new pathogen strains that can be virulent and cause disease on supposedly resistant host. In this context, engineering durable resistance by manipulating genes involved in NHR is an attractive approach for sustainable agriculture. Several genes involved in NHR have been characterized for their role in plant defense. In this review, we report genes involved in NHR identified to date and highlight a few examples where genes involved in NHR have been used to confer resistance in crop plants against economically important diseases.
大多数潜在的病原体无法在自然界中发现的大量植物上建立毒力。这种生物体在不触发典型抗性（R）基因的情况下表现出抵抗病原体毒力的内在特性，被称为非寄主抗性（NHR）。虽然宿主抗性涉及到真核 R 蛋白对病原体激发子（如无毒因子）的识别，但 NHR 的机制似乎不太明显，通常涉及多个基因。我们通常可以分两步来描述 NHR：1）入侵前抗性，无论是被动的还是主动的，它可以限制病原体进入宿主，2）入侵后抗性，一种主动的防御反应，通常会导致类似程序性细胞死亡和活性氧积累的过敏反应。虽然病原体相关分子模式触发的免疫（PTI）通常对非寄主病原体有效，但效应物触发的免疫（ETI）对宿主和非宿主病原体都有效。适应性病原体与其抗性宿主植物之间的长期相互作用导致共同进化，这可能导致新的病原体菌株对原本抗性的宿主具有毒力并引起疾病。在这种情况下，通过操纵与 NHR 相关的基因来工程化持久抗性是可持续农业的一种有吸引力的方法。已经对涉及 NHR 的几个基因进行了特征描述，以了解它们在植物防御中的作用。在这篇综述中，我们报告了迄今为止鉴定的涉及 NHR 的基因，并强调了几个例子，其中涉及 NHR 的基因已被用于赋予作物植物对经济上重要疾病的抗性。
