New Neotyphodium endophyte species from the grass tribes Stipeae and Meliceae

Abstract

Several species of Achnatherum (grass tribe Stipeae) and Melica (tribe Meliceae) typically are infected by nonpathogenic, seed-transmissible fungi with characteristics of Neotyphodium species (anamorphic Clavicipitaceae). Molecular phylogenetic studies clearly have distinguished the endophytes from Achnatherum inebrians (from Xinjiang Province, China), A. robustum and A. eminens (both from North America) and indicate that the A. inebrians endophyte comprises a unique nonhybrid lineage within the Epichloë and Neotyphodium phylogeny, whereas the endophytes of A. robustum, and A. eminens are hybrids with multiple Epichloë species (holomorphic Clavicipitaceae) as ancestors. Likewise distinct hybrid origins are indicated for Neotyphodium species from the European Melica species, M. ciliata and M. transsilvanica, the South African species M. decumbens and M. racemosa, and the South American species M. stuckertii. Neotyphodium species have been described from A. inebrians from Gansu Province, China, (N. gansuense), A. eminens (N. chisosum), M. stuckertii (N. tembladerae) and the South African Melica species (N. melicicola). However the endophytes from A. robustum and the European Melica species have not been described and the phylogenetic relationships of N. gansuense have not been investigated. Here we report a comprehensive study of morphological features and phylogenetic analyses of β-tubulin and actin gene sequences on an expanded collection of endophytes from the Stipeae and Meliceae. These data provide a firm foundation for the description of two new Neotyphodium species, N. guerinii from M. ciliata and M. transsilvanica, and N. funkii from A. robustum. We also propose the new variety, N. gansuense var. inebrians for endophytes of A. inebrians from Xinjiang Province, which are morphologically and phylogenetically distinct from, yet clearly related to, N. gansuense from Gansu Province.

• Achnatherum
• Clavicipitaceae
• epichloë endophytes
• evolution
• grasses
• hybridization
• Melica
• Poaceae
• symbiosis

We thank A. Leuchtmann (ETH Zürich, Switzerland), T.A. Jones (USDA, Utah, USA) and C.O. Miles (AgResearch Ltd., New Zealand) for provision of endophyte-infected grasses and seeds and J. Schmid (Massey University, New Zealand) for helping refine techniques of in planta molecular analysis of endophytes. A. Leuchtmann also provided advice on botanical Latin. We thank W. Hollin, A.D. Byrd, L. Gill and K.K. Schweri for able laboratory assistance. Sequences were analyzed at the University of Kentucky Advanced Genetic Technologies Center, staffed by K.G. Lindstrom, J.L. Wiseman and V.-G. Puram. This research was supported by the National Science Foundation grant DEB-9707427, USDA-CSREES grant 2005-34457-15712, and the National Key Basic Research Program (973) of China (2007 CB108902).