In nature, plants are constantly colonized by a massive diversity of microbes engaged in mutualistic, pathogenic, or commensal relationships with the host. Molecular patterns present in these microbes activate pattern-triggered immunity (PTI), which detects microbes in the apoplast or at the tissue surface. Whether and how PTI distinguishes among soil-borne pathogens, opportunistic pathogens, and commensal microbes within the soil microbiota remains unclear. PTI is a multi-modal series of molecular events initiated by pattern perception, such as Ca2+ influx, reactive oxygen burst, and extensive transcriptional and metabolic reprogramming. These short-term responses may manifest within minutes to hours, while the long-term consequences of chronic PTI activation persist for days to weeks. Chronic activation of PTI is detrimental to plant growth, so plants need to coordinate growth and defense depending on the surrounding biotic and abiotic environments. Recent studies have demonstrated that root-associated commensal microbes can activate or suppress immune responses to variable extents, clearly pointing to the role of PTI in root-microbiota interactions. However, the molecular mechanisms by which root commensals interfere with root immunity and root immunity modulates microbial behavior remain largely elusive. Here, with a focus on the difference between short-term and long-term PTI responses, we summarize what is known about microbial interference with host PTI, especially in the context of root microbiota. We emphasize some missing pieces that remain to be characterized to promote the ultimate understanding of the role of plant immunity in root-microbiota interactions.

中文翻译：

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PTI 激活的长期后果及其根相关微生物群的操纵

在自然界中，植物不断被大量与宿主存在互利、致病或共生关系的微生物定殖。这些微生物中存在的分子模式会激活模式触发免疫（PTI），从而检测质外体或组织表面的微生物。 PTI 是否以及如何区分土壤微生物群内的土传病原体、机会性病原体和共生微生物仍不清楚。 PTI 是由模式感知引发的一系列多模式分子事件，例如 Ca2+ 流入、活性氧爆发以及广泛的转录和代谢重编程。这些短期反应可能会在几分钟到几小时内显现，而慢性 PTI 激活的长期后果会持续数天到数周。 PTI的慢性激活不利于植物生长，因此植物需要根据周围的生物和非生物环境来协调生长和防御。最近的研究表明，与根相关的共生微生物可以不同程度地激活或抑制免疫反应，这清楚地表明了 PTI 在根-微生物群相互作用中的作用。然而，根共生体干扰根免疫和根免疫调节微生物行为的分子机制仍然很大程度上难以捉摸。在这里，我们重点关注短期和长期 PTI 反应之间的差异，总结了微生物对宿主 PTI 干扰的已知信息，特别是在根部微生物群的背景下。我们强调一些仍有待表征的缺失部分，以促进对植物免疫在根部微生物群相互作用中的作用的最终理解。