Department of Biology, Duke University, Durham, NC, USA.
Howard Hughes Medical Institute, Duke University, Durham, NC, USA.
Nat Plants. 2023 Sep;9(9):1468-1480. doi: 10.1038/s41477-023-01501-1. Epub 2023 Aug 17.
Although many studies have shown that microbes can ectopically stimulate or suppress plant immune responses, the fundamental question of whether the entire preexisting microbiota is indeed required for proper development of plant immune response remains unanswered. Using a recently developed peat-based gnotobiotic plant growth system, we found that Arabidopsis grown in the absence of a natural microbiota lacked age-dependent maturation of plant immune response and were defective in several aspects of pattern-triggered immunity. Axenic plants exhibited hypersusceptibility to infection by the bacterial pathogen Pseudomonas syringae pv. tomato DC3000 and the fungal pathogen Botrytis cinerea. Microbiota-mediated immunocompetence was suppressed by rich nutrient conditions, indicating a tripartite interaction between the host, microbiota and abiotic environment. A synthetic microbiota composed of 48 culturable bacterial strains from the leaf endosphere of healthy Arabidopsis plants was able to substantially restore immunocompetence similar to plants inoculated with a soil-derived community. In contrast, a 52-member dysbiotic synthetic leaf microbiota overstimulated the immune transcriptome. Together, these results provide evidence for a causal role of a eubiotic microbiota in gating proper immunocompetence and age-dependent immunity in plants.
虽然许多研究表明微生物可以异位刺激或抑制植物的免疫反应，但一个基本问题仍然没有答案，即植物的整个固有微生物组是否确实是适当发育植物免疫反应所必需的。利用最近开发的基于泥炭的无菌植物生长系统，我们发现，在没有天然微生物组的情况下生长的拟南芥缺乏依赖年龄的植物免疫反应成熟，并且在模式触发免疫的几个方面存在缺陷。无菌植物对细菌病原体丁香假单胞菌 pv.番茄 DC3000 和真菌病原体 Botrytis cinerea 的感染表现出超敏性。微生物组介导的免疫能力受到丰富营养条件的抑制，表明宿主、微生物组和非生物环境之间存在三方相互作用。由来自健康拟南芥叶片内生生境的 48 种可培养细菌菌株组成的合成微生物组能够显著恢复类似于用土壤衍生群落接种的植物的免疫能力。相比之下，一个由 52 个成员组成的失调的合成叶片微生物组过度刺激了免疫转录组。总之，这些结果为有益微生物组在植物适当免疫能力和年龄依赖性免疫中的门控作用提供了证据。
