Graduate School of Agricultural Science, Tohoku University, Sendai, Japan.
Department of Biology, Utrecht University, Utrecht, the Netherlands.
Commun Biol. 2021 Aug 9;4(1):947. doi: 10.1038/s42003-021-02482-7.
Land plant genomes carry tens to hundreds of Resistance (R) genes to combat pathogens. The induction of antiviral R-gene-mediated resistance often results in a hypersensitive response (HR), which is characterized by virus containment in the initially infected tissues and programmed cell death (PCD) of the infected cells. Alternatively, systemic HR (SHR) is sometimes observed in certain R gene-virus combinations, such that the virus systemically infects the plant and PCD induction follows the spread of infection, resulting in systemic plant death. SHR has been suggested to be the result of inefficient resistance induction; however, no quantitative comparison has been performed to support this hypothesis. In this study, we report that the average number of viral genomes that establish cell infection decreased by 28.7% and 12.7% upon HR induction by wild-type cucumber mosaic virus and SHR induction by a single-amino acid variant, respectively. These results suggest that a small decrease in the level of resistance induction can change an HR to an SHR. Although SHR appears to be a failure of resistance at the individual level, our simulations imply that suicidal individual death in SHR may function as an antiviral mechanism at the population level, by protecting neighboring uninfected kin plants.
陆生植物基因组携带数十到数百个抗性（R）基因，以抵御病原体。抗病毒 R 基因介导的抗性的诱导通常会导致过敏反应（HR），其特征是病毒在最初感染的组织中被限制，以及受感染细胞的程序性细胞死亡（PCD）。或者，在某些 R 基因-病毒组合中，有时会观察到系统性 HR（SHR），使得病毒系统性地感染植物，并且在感染传播后会诱导 PCD，导致系统性植物死亡。SHR 被认为是抗性诱导效率低下的结果；然而，没有进行定量比较来支持这一假设。在这项研究中，我们报告说，野生型黄瓜花叶病毒诱导 HR 以及单个氨基酸变异体诱导 SHR 时，分别使建立细胞感染的病毒基因组数量平均减少了 28.7%和 12.7%。这些结果表明，抗性诱导水平的微小降低可以将 HR 转变为 SHR。尽管 SHR 似乎是个体水平上抗性的失败，但我们的模拟表明，SHR 中的自杀性个体死亡可能在种群水平上作为一种抗病毒机制发挥作用，保护邻近的未感染亲缘植物。
