Key Laboratory of Horticultural Plant Biology (MOE), College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, 430070, China.
Sci China Life Sci. 2018 Feb;61(2):138-147. doi: 10.1007/s11427-017-9237-4. Epub 2018 Jan 9.
Plant resistance (R) proteins are immune receptors that recognize pathogen effectors and trigger rapid defense responses, namely effector-triggered immunity. R protein-mediated pathogen resistance is usually race specific. During plant-pathogen coevolution, plant genomes accumulated large numbers of R genes. Even though plant R genes provide important natural resources for breeding disease-resistant crops, their presence in the plant genome comes at a cost. Misregulation of R genes leads to developmental defects, such as stunted growth and reduced fertility. In the past decade, many microRNAs (miRNAs) have been identified to target various R genes in plant genomes. miRNAs reduce R gene levels under normal conditions and allow induction of R gene expression under various stresses. For these reasons, we consider R genes to be double-edged "swords" and miRNAs as molecular "scabbards". In the present review, we summarize the contributions and potential problems of these "swords" and discuss the features and production of the "scabbards", as well as the mechanisms used to pull the "sword" from the "scabbard" when needed.
植物抗性（R）蛋白是识别病原体效应物并触发快速防御反应的免疫受体，即效应子触发的免疫。R 蛋白介导的病原体抗性通常具有特定的种族特异性。在植物-病原体共同进化过程中，植物基因组积累了大量的 R 基因。尽管植物 R 基因为培育抗病作物提供了重要的自然资源，但它们在植物基因组中的存在是有代价的。R 基因的失调会导致发育缺陷，如生长迟缓和繁殖力降低。在过去的十年中，已经鉴定出许多 microRNAs（miRNAs）可以靶向植物基因组中的各种 R 基因。miRNAs 在正常条件下降低 R 基因水平，并允许在各种胁迫下诱导 R 基因表达。基于这些原因，我们认为 R 基因是双刃剑，而 miRNAs 则是分子剑鞘。在本综述中，我们总结了这些“剑”的贡献和潜在问题，并讨论了“鞘”的特征和产生，以及在需要时将“剑”从“鞘”中拔出的机制。
