Plant Pathology Group, Institute of Integrative Biology, ETH Zurich, Zurich, Switzerland.
Mol Phylogenet Evol. 2011 Feb;58(2):192-7. doi: 10.1016/j.ympev.2010.12.002. Epub 2010 Dec 9.
Plant pathogens emerge in agro-ecosystems following different evolutionary mechanisms over different time scales. Previous analyses based on sequence variation at six nuclear loci indicated that Mycosphaerella graminicola diverged from an ancestral population adapted to wild grasses during the process of wheat domestication approximately 10,500 years ago. We tested this hypothesis by conducting coalescence analyses based on four mitochondrial loci using 143 isolates that included four closely related pathogen species originating from four continents. Pathogen isolates from bread and durum wheat were included to evaluate the emergence of specificity towards these hosts in M. graminicola. Although mitochondrial and nuclear genomes differed greatly in degree of genetic variability, their coalescence was remarkably congruent, supporting the proposed origin of M. graminicola through host tracking. The coalescence analysis was unable to trace M. graminicola host specificity through recent evolutionary time, indicating that the specificity towards durum or bread wheat emerged following the domestication of the pathogen on wheat.
植物病原体通过不同的进化机制在农业生态系统中出现，其时间跨度也不同。基于六个核基因座的序列变异的先前分析表明，麦类球腔菌大约在 10500 年前的小麦驯化过程中从一个适应野生草的祖先种群中分化出来。我们通过使用来自四大洲的四个密切相关的病原体物种的 143 个分离物，基于四个线粒体基因座进行了合并分析，以验证这一假设。从面包和硬质小麦中分离出的病原体被包括在内，以评估麦类球腔菌对这些宿主的特异性的出现。尽管线粒体和核基因组在遗传变异程度上有很大差异，但它们的合并非常一致，支持了麦类球腔菌通过跟踪宿主而产生的假说。合并分析无法通过最近的进化时间追踪麦类球腔菌的宿主特异性，这表明其对硬质小麦或面包小麦的特异性是在病原体对小麦的驯化之后出现的。
