U.S. Department of Agriculture, Agricultural Research Service, Beltsville, MD 20705, USA.
Mycologia. 2012 Sep-Oct;104(5):1085-96. doi: 10.3852/11-317. Epub 2012 Apr 9.
Colletotrichum is a cosmopolitan, anamorphic fungal genus responsible for anthracnose disease in hundreds of plant species worldwide, including members of the Poaceae. Anthracnose disease of the widely planted, non-native, warm-season lawn grass, Eremochloae ophiuroides (centipedegrass), is commonly encountered in the southern United States, but the causal agent has never been identified. We use DNA sequence data from modern cultures and archival fungarium specimens in this study to determine the identity of the fungus responsible for centipedegrass anthracnose disease and provide experimental confirmation of pathogenicity. C. eremochloae sp. nov., a pathogen of centipedegrass, is proposed based on phylogenetic evidence from four sequence markers (Apn2, Apn2/ Mat1, Sod2, ITS). C. eremochloae isolates from centipedegrass shared common morphology and phenotype with C. sublineola, a destructive pathogen of cultivated sorghum and Johnsongrass weeds (Sorghum halepense, S. vulgaris). Molecular phylogenetic analysis identified C. eremochloae and C. sublineola as closely related sister taxa, but genealogical concordance supported their distinction as unique phylogenetic species. Fixed nucleotide differences between C. eremochloae and C. sublineola were observed from collections of these fungi spanning 105 y, including the 1904 lectotype specimen of C. sublineola. C. eremochloae was identified from a fungarium specimen of centipedegrass intercepted at a USA port from a 1923 Chinese shipment; the multilocus sequence from this specimen was identical to modern samples of the fungus. Thus, it appears that the fungus might have migrated to the USA around the same time that centipedegrass first was introduced to the USA in 1916 from China, where the grass is indigenous. The new species C. eremochloae is described and illustrated, along with a description and discussion of C. sublineola based on the lectotype and newly designated epitype.
炭疽菌是一种世界性的、无性的真菌属，负责全球数百种植物物种的炭疽病，包括禾本科植物。广泛种植的、非本地的、暖季草坪草——蜈蚣草（蜈蚣草）的炭疽病在美国南部很常见，但致病因子从未被确定过。在这项研究中，我们使用现代培养物和档案标本的 DNA 序列数据来确定负责蜈蚣草炭疽病的真菌的身份，并提供致病性的实验确认。根据来自四个序列标记（Apn2、Apn2/Mat1、Sod2、ITS）的系统发育证据，提出了蜈蚣草炭疽菌的新种——C. eremochloae sp. nov.。从蜈蚣草分离出的 C. eremochloae 与 C. sublineola 具有共同的形态和表型，C. sublineola 是栽培高粱和 Johnsongrass 杂草（高粱、普通高粱）的破坏性病原体。分子系统发育分析将 C. eremochloae 和 C. sublineola 鉴定为密切相关的姊妹分类群，但谱系一致性支持将它们区分开来作为独特的系统发育种。在跨越 105 年的这些真菌的采集物中观察到 C. eremochloae 和 C. sublineola 之间固定的核苷酸差异，包括 1904 年 C. sublineola 的 lectotype 标本。从 1923 年从中国运往美国的一个港口截获的蜈蚣草标本中鉴定出 C. eremochloae；该标本的多点序列与真菌的现代样本完全相同。因此，这种真菌似乎是在 1916 年蜈蚣草首次从中国引入美国的同时迁移到美国的，而蜈蚣草原产于中国。描述并图示了新种 C. eremochloae，并基于 lectotype 和新指定的 epitype 描述和讨论了 C. sublineola。
