Plant immune system activation is necessary for efficient interaction with auxin secreting beneficial bacteria

Plants continuously monitor the presence of microorganisms through their immune system to establish an adaptive response. Unlike immune recognition of pathogenic bacteria, how beneficial bacteria interact with the plant immune system is not well understood. Analysis of colonization of Arabidopsis thaliana by auxin producing beneficial bacteria revealed that activation of the plant immune system is necessary for efficient bacterial colonization and auxin secretion. A feedback loop is established in which bacterial colonization triggers an immune reaction and production of reactive oxygen species, which, in turn, stimulate auxin production by the bacteria. Auxin promotes bacterial survival and efficient root colonization, allowing the bacteria to inhibit fungal infection and promote plant health.植物通过自身免疫系统持续监测微生物的存在，以启动适应性免疫应答。与对病原细菌的免疫识别不同，学界对有益菌与植物免疫系统的互作机制仍知之甚少。对产生长素有益菌定殖拟南芥（Arabidopsis thaliana）的分析显示，激活植物免疫系统是实现高效细菌定殖与生长素分泌的必要条件。由此形成了一套反馈环路：细菌定殖会触发免疫反应与活性氧（reactive oxygen species）的产生，而后者又会反过来促进细菌合成生长素。生长素可促进细菌存活与高效根系定殖，使细菌能够抑制真菌侵染并助力植物健康生长。