• The genes required for host‐specific pathogenicity in Fusarium oxysporum can be acquired through horizontal chromosome transfer (HCT). However, it is unknown if HCT commonly contributes to the diversification of pathotypes.
• Using comparative genomics and pathogenicity phenotyping, we explored the role of HCT in the evolution of F. oxysporum f. sp. fragariae, the cause of Fusarium wilt of strawberry, with isolates from four continents.
• We observed two distinct syndromes: one included chlorosis (‘yellows‐fragariae’) and the other did not (‘wilt‐fragariae’). All yellows‐fragariae isolates carried a predicted pathogenicity chromosome, ‘chr^Y‐frag’, that was horizontally transferred at least four times. chr^Y‐frag was associated with virulence on specific cultivars and encoded predicted effectors that were highly upregulated during infection. chr^Y‐frag was not present in wilt‐fragariae; isolates causing this syndrome evolved pathogenicity independently. All origins of F. oxysporum f. sp. fragariae occurred outside of the host’s native range.
• Our data support the conclusion that HCT is widespread in F. oxysporum, but pathogenicity can also evolve independently. The absence of chr^Y‐frag in wilt‐fragariae suggests that multiple, distinct pathogenicity chromosomes can confer the same host specificity. The wild progenitors of cultivated strawberry (Fragaria × ananassa) did not co‐evolve with this pathogen, yet we discovered several sources of genetic resistance.

中文翻译：

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水平染色体转移和独立进化驱动尖孢镰刀菌的多样化。 sp。草莓

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  尖镰孢宿主特异性致病性所需的基因可以通过水平染色体转移（HCT）获得。然而，尚不清楚 HCT 是否通常有助于致病型的多样化。
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  利用比较基因组学和致病性表型分析，我们探讨了 HCT 在F. oxysporum f 进化中的作用。 sp。草莓镰刀菌，草莓枯萎病的病原菌，分离物来自四大洲。
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  我们观察到两种不同的综合征：一种包括褪绿症（“黄化-草莓”），另一种则不包括（“枯萎-草莓”）。所有黄草莓分离株均携带预测的致病性染色体“chr ^Y-frag ”，该染色体水平转移至少四次。 chr ^Y-frag与特定品种的毒力相关，并编码在感染过程中高度上调的预测效应子。青霉中不存在 chr ^Y-frag ；引起这种综合征的分离株独立进化出致病性。 F. oxysporum f. 的所有来源sp。草莓病发生在宿主的原生范围之外。
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  我们的数据支持这样的结论：HCT 在尖孢镰刀菌中广泛存在，但致病性也可以独立进化。青枯病菌中^{Y 片段}的缺失表明，多个不同的致病性染色体可以赋予相同的宿主特异性。栽培草莓（ Fragaria × ananassa ）的野生祖先并未与这种病原体共同进化，但我们发现了多种遗传抗性来源。