Grenz Kristina, Chia Khong-Sam, Turley Emma K, Tyszka Alexa S, Atkinson Rebecca E, Reeves Jacob, Vickers Martin, Rejzek Martin, Walker Joseph F, Carella Philip
Cell and Developmental Biology, John Innes Centre, Norwich NR4 7UH, UK.
Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL 60607, USA.
Cell Host Microbe. 2025 Jan 8;33(1):20-29.e5. doi: 10.1016/j.chom.2024.11.014. Epub 2024 Dec 19.
The Pseudomonas syringae species complex harbors a diverse range of pathogenic bacteria that can infect hosts across the plant kingdom. However, much of our current understanding of P. syringae is centered on its infection of flowering plants. We took a comparative approach to understand how P. syringae infects evolutionarily divergent plants. We identified P. syringae isolates causing disease in the liverwort Marchantia polymorpha, the fern Ceratopteris richardii, and the flowering plant Nicotiana benthamiana, which last shared a common ancestor >500 million years ago. Phytotoxin-enriched phylogroup (PG) 2 isolates of P. syringae are virulent in non-flowering plants, relying on type-3 effectors and the lipopeptide phytotoxin syringomycin. Ectopic syringomycin promotes tissue necrosis, activates conserved stress-related genes, and enhances in planta bacterial growth of toxin-deficient PGs in Marchantia. Collectively, our research reveals a key role for syringomycin in promoting Pseudomonas colonization, which works alongside effectors to antagonize an exceptionally wide spectrum of land plants.
丁香假单胞菌物种复合体包含多种致病细菌，可感染整个植物界的宿主。然而，我们目前对丁香假单胞菌的了解大多集中在其对开花植物的感染上。我们采用比较方法来了解丁香假单胞菌如何感染进化上不同的植物。我们鉴定出在苔藓地钱、蕨类植物里氏巢蕨和开花植物本氏烟草中引起病害的丁香假单胞菌分离株，这三种植物最后一个共同祖先生活在5亿多年前。富含植物毒素的丁香假单胞菌系统发育群（PG）2分离株在非开花植物中具有毒性，依赖于Ⅲ型效应子和脂肽植物毒素丁香霉素。异位表达的丁香霉素会促进组织坏死，激活保守的胁迫相关基因，并增强地钱中毒素缺陷型PGs在植物体内的细菌生长。总的来说，我们的研究揭示了丁香霉素在促进假单胞菌定殖中的关键作用，它与效应子协同作用，对抗范围异常广泛的陆地植物。
