Department of Plant Science and Landscape Architecture, University of Maryland, 2112 Plant Science Building, College Park, Maryland, 20742.
Evolution. 2013 Oct;67(10):2823-37. doi: 10.1111/evo.12169. Epub 2013 Jun 17.
Host jumps by microbial symbionts are often associated with bursts of species diversification driven by the exploitation of new adaptive zones. The objective of this study was to infer the evolution of habitat preference (decaying plants, soil, living fungi, and living plants), and nutrition mode (saprotrophy and mycoparasitism) in the fungal genus Trichoderma to elucidate possible interkingdom host jumps and shifts in ecology. Host and ecological role shifts were inferred by phylogenetic analyses and ancestral character reconstructions. The results support several interkingdom host jumps and also show that the preference for a particular habitat was gained or lost multiple times. Diversification analysis revealed that mycoparasitism is associated with accelerated speciation rates, which then suggests that this trait may be linked to the high number of species in Trichoderma. In this study it was also possible to infer the cryptic roles that endophytes or soil inhabitants play in their hosts by evaluating their closest relatives and determining their most recent ancestors. Findings from this study may have implications for understanding certain evolutionary processes such as species radiations in some hyperdiverse groups of fungi, and for more applied fields such as the discovery and development of novel biological control strategies.
微生物共生体的宿主跳跃通常与物种多样化的爆发有关，这些爆发是由对新适应区的利用驱动的。本研究的目的是推断真菌属 Trichoderma 中栖息地偏好（腐烂植物、土壤、活真菌和活植物）和营养模式（腐生和菌寄生）的进化，以阐明可能的跨界宿主跳跃和生态位转变。通过系统发育分析和祖先特征重建来推断宿主和生态角色的转变。研究结果支持了多次跨界宿主跳跃，也表明对特定栖息地的偏好是多次获得或丧失的。多样化分析表明，菌寄生与加速物种形成率有关，这表明该特征可能与 Trichoderma 中大量物种有关。在这项研究中，还可以通过评估其最近的亲缘关系并确定其最近的祖先，推断出内生菌或土壤生物在其宿主中扮演的隐蔽角色。本研究的结果可能对理解某些进化过程具有意义，例如某些真菌超多样化群体中的物种辐射，以及在发现和开发新型生物防治策略等更应用领域。
