Necrotrophic fungi constitute the largest group of plant fungal pathogens that cause heavy crop losses worldwide. Phymatotrichopsis omnivora is a broad host, soil-borne necrotrophic fungal pathogen that infects over 2,000 dicotyledonous plants. The molecular basis of such broad host range is unknown. We conducted cell biology and transcriptomic studies in Medicago truncatula (susceptible), Brachypodium distachyon (resistant/nonhost), and Arabidopsis thaliana (partially resistant) to understand P. omnivora virulence mechanisms. We performed defence gene analysis, gene enrichments, and correlational network studies during key infection stages. We identified that P. omnivora infects the susceptible plant as a traditional necrotroph. However, it infects the partially resistant plant as a hemi-biotroph triggering salicylic acid-mediated defence pathways in the plant. Further, the infection strategy in partially resistant plants is determined by the host responses during early infection stages. Mutant analyses in A. thaliana established the role of small peptides PEP1 and PEP2 in defence against P. omnivora. The resistant/nonhost B. distachyon triggered stress responses involving sugars and aromatic acids. Bdwat1 mutant analysis identified the role of cell walls in defence. This is the first report that describes the plasticity in infection strategies of P. omnivora providing insights into broad host range.

中文翻译：

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杂食毛丝菌感染策略的可塑性取决于宿主和非宿主植物的反应。


坏死营养真菌是最大的植物真菌病原体群，导致全球农作物严重损失。杂食毛丝菌是一种宿主广泛的土传坏死性真菌病原体，可感染 2,000 多种双子叶植物。如此广泛的宿主范围的分子基础尚不清楚。我们对蒺藜苜蓿（易感）、二穗短柄草（抗性/非寄主）和拟南芥（部分抗性）进行了细胞生物学和转录组学研究，以了解杂食紫花苜蓿的毒力机制。我们在关键感染阶段进行了防御基因分析、基因富集和相关网络研究。我们发现杂食假单胞菌作为传统的死体营养生物感染易感植物。然而，它作为半生物营养菌感染部分抗性植物，触发植物中水杨酸介导的防御途径。此外，部分抗性植物的感染策略由早期感染阶段的宿主反应决定。对拟南芥的突变分析证实了小肽 PEP1 和 PEP2 在防御杂食拟南芥中的作用。抗性/非寄主二穗芽孢杆菌引发了涉及糖和芳香酸的应激反应。 Bdwat1 突变体分析确定了细胞壁在防御中的作用。这是第一份描述杂食假单胞菌感染策略可塑性的报告，提供了对广泛宿主范围的见解。