Summary The barley disease Septoria Speckled Leaf Blotch, caused by the fungus Zymoseptoria passerinii, last appeared in North America in the early 2000s. Although rare in crops, field sampling of wild grasses in the Middle East revealed the disease persistence in wild barley. Identification of Z. passerinii in various wild barley species prompted us to examine genomic signatures of host specialization and trace the emergence of the domesticated‐barley‐infecting lineage. Furthermore, we applied virulence assays and confocal laser microscopy to evaluate whether the disease development differs between wild and domesticated barley. Wild‐ and domesticated‐host‐infecting populations have diverged, and phylogenetic relationships support the evolution of sympatric host‐specialized lineages in wild hosts. Cross‐virulence assays showed that Z. passerinii from domesticated hosts infect domesticated barley and its wild ancestor, Hordeum spontaneum. However, wild isolates from Iran did not infect domesticated barley. Wild and domesticated pathosystems have similar disease timing and progression, suggesting its persistence does not depend on a shorter period of incubation. The study supports that a wide range of hosts can foster the evolution of host‐specialized lineages in sympatry and provide novel insights into the evolution of understudied fungal pathogens on wild hosts.

中文翻译：

---

自然生态系统中真菌植物病原体 Zymoseptoria passerinii 的同域宿主特化谱系的进化


摘要 大麦病害 Septoria 斑点叶斑点是由真菌 Zymoseptoria passerinii 引起的，最后一次出现在北美是在 2000 年代初。虽然在农作物中很少见，但对中东野草的田间采样表明，这种疾病在野生大麦中持续存在。在各种野生大麦物种中鉴定出 Z. passerinii 促使我们检查宿主特化的基因组特征并追踪驯化大麦感染谱系的出现。此外，我们应用毒力测定和共聚焦激光显微镜来评估野生大麦和驯化大麦之间的疾病发展是否不同。野生和驯化宿主感染种群已经分化，系统发育关系支持野生宿主中同域宿主特化谱系的进化。交叉毒力测定表明，来自驯化宿主的雀形目 Z. passerinii 感染驯化大麦及其野生祖先 Hordeum spontaneum。然而，来自伊朗的野生分离株并未感染驯化大麦。野生和驯化病理系统具有相似的疾病时间和进展，表明其持久性不依赖于较短的潜伏期。该研究支持广泛的宿主可以促进宿主特化谱系的同源进化，并为野生宿主上研究不足的真菌病原体的进化提供新的见解。