Max Planck Institute for Biology Tübingen, Tübingen, 72076, Germany.
Max Planck Institute of Molecular Plant Physiology, Potsdam-Golm, 14476, Germany.
New Phytol. 2023 Dec;240(5):1961-1975. doi: 10.1111/nph.19241. Epub 2023 Sep 4.
The opportunistic pathogen Pseudomonas viridiflava colonizes > 50 agricultural crop species and is the most common Pseudomonas in the phyllosphere of European Arabidopsis thaliana populations. Belonging to the P. syringae complex, it is genetically and phenotypically distinct from well-characterized P. syringae sensu stricto. Despite its prevalence, we lack knowledge of how A. thaliana responds to its native isolates at the molecular level. Here, we characterize the host response in an A. thaliana - P. viridiflava pathosystem. We measured host and pathogen growth in axenic infections and used immune mutants, transcriptomics, and metabolomics to determine defense pathways influencing susceptibility to P. viridiflava infection. Infection with P. viridiflava increased jasmonic acid (JA) levels and the expression of ethylene defense pathway marker genes. The immune response in a susceptible host accession was delayed compared with a tolerant one. Mechanical injury rescued susceptibility, consistent with an involvement of JA. The JA/ethylene pathway is important for suppression of P. viridiflava, yet suppression capacity varies between accessions. Our results shed light on how A. thaliana can suppress the ever-present P. viridiflava, but further studies are needed to understand how P. viridiflava evades this suppression to spread broadly across A. thaliana populations.
机会性病原体绿脓假单胞菌定植于 > 50 种农业作物物种，是欧洲拟南芥种群叶际中最常见的假单胞菌。它属于丁香假单胞菌复合体，在遗传和表型上与特征明确的丁香假单胞菌有明显区别。尽管它很普遍，但我们仍然缺乏对拟南芥如何在分子水平上对其本地分离株做出反应的了解。在这里，我们在拟南芥-绿脓假单胞菌病理系统中对宿主反应进行了表征。我们在无菌感染中测量了宿主和病原体的生长，并使用免疫突变体、转录组学和代谢组学来确定影响绿脓假单胞菌感染易感性的防御途径。绿脓假单胞菌感染增加了茉莉酸 (JA) 水平和乙烯防御途径标记基因的表达。与耐受宿主品系相比，易感宿主品系的免疫反应延迟。机械损伤挽救了易感性，这与 JA 的参与一致。JA/乙烯途径对绿脓假单胞菌的抑制很重要，但在不同品系之间抑制能力不同。我们的研究结果揭示了拟南芥如何能够抑制普遍存在的绿脓假单胞菌，但需要进一步研究来了解绿脓假单胞菌如何逃避这种抑制以在拟南芥种群中广泛传播。
