HOST JUMPING ONTO CLOSE RELATIVES AND ACROSS KINGDOMS BY TYRANNICORDYCEPS (CLAVICIPITACEAE) GEN. NOV AND USTILAGINOIDEA_(CLAVICIPITACEAE)
HOST JUMPING ONTO CLOSE RELATIVES AND ACROSS KINGDOMS BY TYRANNICORDYCEPS (CLAVICIPITACEAE) GEN. NOV AND USTILAGINOIDEA_(CLAVICIPITACEAE)
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DOI：
10.3732/ajb.1100124
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发表时间：
2012-03-01
影响因子：
3
通讯作者：
Spatafora, Joseph W.
中科院分区：
文献类型：
--
作者：
Kepler, Ryan M.;Sung, Gi-Ho;Spatafora, Joseph W.
研究前提：本研究旨在加深对允许真菌病原体在宿主之间移动的条件的了解。麦角科包含利用三个生命界的宿主的真菌病原体，其特征是植物、动物和真菌之间存在多个界间宿主转移。黑粉菌亚科部落可能代表植物发病机制的第三个起源，尽管这些物种仍未得到充分研究。引起麦角的真菌病原体在形态学上与麦角菌科相关，但尚未纳入系统发育研究。黑粉菌科和麦角病原体的放置将允许区分宿主栖息地和宿主相关性假设，作为麦角菌科系统发育多样化的机制。方法：为麦角菌科组装了多基因数据集，以测试黑粉菌科和麦角菌以及麦角菌寄生虫虫草菌的系统发育放置和祖先特征状态重建。还对有性和无性状态进行了显微镜形态学观察。 主要结果： U. virens 和 U. dichromonae 的系统发育位置代表了麦角菌科植物致病生活方式的第三次获得。弗氏冬虫夏草也被归入麦角冬虫科并被确认为新属暴虫草属。祖先特征状态重建表明，最初感染半翅目昆虫宿主促进了植物致病生活方式的后续变化。据推测，T. fratricida 的祖先是从草类跳跃到草类病原体的。结论：宿主栖息地假说最好地解释了麦角菌科和整个肉座菌目中宿主隶属关系的动态演化。同一栖息地的共存使得宿主可以从动物转移到植物，从植物转移到真菌。
Premise of study: This research seeks to advance understanding of conditions allowing movement of fungal pathogens among hosts. The family Clavicipitaceae contains fungal pathogens exploiting hosts across three kingdoms of life in a pattern that features multiple interkingdom host shifts among plants, animals, and fungi. The tribe Ustilaginoideae potentially represents a third origin of plant pathogenesis, although these species remain understudied. Fungal pathogens that cause ergot are linked morphologically with Clavicipitaceae, but are not yet included in phylogenetic studies. The placement of Ustilaginoideae and ergot pathogens will allow differentiation between the host habitat and host relatedness hypotheses as mechanisms of phylogenetic diversification of Clavicipitaceae.Methods: A multigene data set was assembled for Clavicipitaceae to test phylogenetic placement and ancestral character-state reconstructions for Ustilaginoidea virens and U. dichromonae as well as the ergot mycoparasite Cordyceps fratricida. Microscopic morphological observations of sexual and asexual states were also performed.Key results: Phylogenetic placement of U. virens and U. dichromonae represents a third acquisition of the plant pathogenic lifestyle in Clavicipitaceae. Cordyceps fratricida was also placed in Clavicipitaceae and recognized as a new genus Tyrannicordyceps. Ancestral character state reconstructions indicate initially infecting hemipteran insect hosts facilitates subsequent changes to a plant pathogenic lifestyle. The ancestor of T. fratricida is inferred to have jumped from grasses to pathogens of grasses.Conclusions: The host habitat hypothesis best explains the dynamic evolution of host affiliations seen in Clavicipitaceae and throughout Hypocreales. Co-occurrence in the same habitat has allowed for host shifts from animals to plants, and from plants to fungi.