Convergent evolution of phytopathogenicity is poorly described, especially among multiple strains of a single microbial species. We investigated this phenomenon with genetically diverse isolates of Fusarium oxysporum f. sp. fragariae (Fof) that cause one of two syndromes: chlorosis and wilting (the ‘yellows-fragariae’ pathotype), or only wilting (the ‘wilt-fragariae’ pathotype). We challenged strawberry (Fragaria × ananassa) plants to root infection by five fungal isolates: three yellows-fragariae, one wilt-fragariae and one that is not pathogenic to strawberry. All Fof isolates had chromosome-level assemblies; three were newly generated. The two pathotypes triggered distinct host responses, especially among phytohormone-associated genes; yellows-fragariae isolates strongly induced jasmonic acid-associated genes, whereas the wilt-fragariae isolate primarily induced ethylene biosynthesis and signalling. The differentially expressed genes on fungal accessory chromosomes were almost entirely distinct between pathotypes. We identified an ~150 kbp ‘pathogenicity island’ that was horizontally transferred between wilt-fragariae strains. This predicted pathogenicity island was enriched with differentially expressed genes whose predicted functions were related to plant infection, and only one of these genes was also upregulated in planta by yellows-fragariae isolates. These results support the conclusion that wilt- and yellows-fragariae cause physiologically distinct syndromes by the expression of discrete repertoires of genes on accessory chromosomes.

中文翻译：

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Fusarium oxysporum f. 的致病型。sp。草莓表达不连续的辅助基因库并在根感染期间诱导不同的宿主转录反应

植物致病性的趋同进化很少被描述，尤其是在单一微生物物种的多个菌株中。我们用Fusarium oxysporum f的遗传多样性分离株研究了这种现象。sp。草莓( Fof ) 导致以下两种综合症之一：萎黄病和萎蔫（'yellows-fragariae '致病型），或仅萎蔫（'wilt-fragariae '致病型）。我们用五种真菌分离株对草莓 ( Fragaria  ×  ananassa ) 植物进行根部感染挑战：三种黄色- 草莓属、一种枯萎病- 草莓属和一种对草莓不致病的真菌。全福分离株具有染色体水平的组装；三个是新产生的。这两种致病型引发了不同的宿主反应，尤其是在植物激素相关基因中；yellows - fragariae分离株强烈诱导茉莉酸相关基因，而野生草莓分离株主要诱导乙烯生物合成和信号传导。真菌辅助染色体上差异表达的基因在致病型之间几乎完全不同。我们确定了一个约 150 kbp 的“致病性岛”，它在野生草莓菌株之间水平转移。这个预测的致病岛富含差异表达的基因，这些基因的预测功能与植物感染有关，并且这些基因中只有一个也被上调在植物中由 yellows-fragariae分离。这些结果支持这样的结论，即野生草莓和黄色草莓通过在辅助染色体上表达离散的基因库而导致生理上不同的综合症。