Department of Botany and Plant Sciences, Center for Plant Cell Biology, Institute of Integrative Genome Biology, University of California at Riverside, Riverside, CA 92521, USA.
College of Life Sciences, Fujian Agricultural and Forestry University, Fuzhou, Fujian 350002, China.
Mol Plant Pathol. 2018 May;19(5):1267-1281. doi: 10.1111/mpp.12607. Epub 2017 Nov 20.
Plant NLR genes encode sensitive immune receptors that can mediate the specific recognition of pathogen avirulence effectors and activate a strong defence response, termed effector-triggered immunity. The expression of NLRs requires strict regulation, as their ability to trigger immunity is dependent on their dose, and overexpression of NLRs results in autoimmunity and massive fitness costs. An elaborate interplay of different mechanisms controlling NLR transcript levels allows plants to maximize their defence capacity, whilst limiting negative impact on their fitness. Global suppression of NLR transcripts may be a prerequisite for the fast evolution of new NLR variants and the expansion of this gene family. Here, we summarize recent progress made towards a comprehensive understanding of NLR transcript-level expression control. Multiple mechanistic steps, including transcription as well as co-/post-transcriptional processing and transcript turn-over, contribute to balanced base levels of NLR transcripts and allow for dynamic adjustments to defence situations.
植物 NLR 基因编码敏感的免疫受体，能够介导对病原体无毒效应物的特异性识别，并激活被称为效应子触发免疫的强烈防御反应。NLR 的表达需要严格的调控，因为它们触发免疫的能力取决于它们的剂量，NLR 的过度表达会导致自身免疫和大量适应度成本。不同机制的精细相互作用控制 NLR 转录本水平，使植物能够最大限度地提高其防御能力，同时限制对其适应性的负面影响。 NLR 转录本的全局抑制可能是新 NLR 变体快速进化和这个基因家族扩张的前提。在这里，我们总结了在全面理解 NLR 转录本水平表达调控方面取得的最新进展。多个机制步骤，包括转录以及共/后转录加工和转录周转率，有助于 NLR 转录本的基础水平平衡，并允许对防御情况进行动态调整。
