Evolutionary Relationships of the Dutch Elm Disease Fungus Ophiostoma novo-ulmi to Other Ophiostoma Species Investigated by Restriction Fragment Length Polymorphism Analysis of the rDNA Region

Authors

  • N. D. Pipe,

    1. Authors' addresses: Department of Biology, Imperial College of Science, Technology and Medicine, London SW7 2AZ, UK;; Forestry Commission Research Agency, Alice Holt Lodge, Farnham, Surrey, GU10 4LH, UK
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  • C. M. Brasier,

    1. Authors' addresses: Department of Biology, Imperial College of Science, Technology and Medicine, London SW7 2AZ, UK;; Forestry Commission Research Agency, Alice Holt Lodge, Farnham, Surrey, GU10 4LH, UK
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  • K. W. Buck

    1. Authors' addresses: Department of Biology, Imperial College of Science, Technology and Medicine, London SW7 2AZ, UK;; Forestry Commission Research Agency, Alice Holt Lodge, Farnham, Surrey, GU10 4LH, UK
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Abstract

Restriction fragment length polymorphisms (RFLPs) in the ribosomal RNA gene (rDNA) region were used to assess relationships between the Dutch elm disease fungi Ophiostoma novo-ulmi and Ophiostoma ulmi, the recently described Himalayan Dutch elm disease pathogen, Ophiostoma himal-ulmi, the morphologically similar sapstain fungi, Ophiostoma piceae and Ophiostoma quercus, and several Ophiostoma species from hardwood trees, including Ophiostoma stenoceras and Ophiostoma proliferum. A distance matrix and cluster analysis indicated that the rDNA region of O. himal-ulmi is more closely related to those of O. novo-ulmi and O. ulmi than to those of O. piceae and O. quercus and is more distantly related to O. stenoceras and the other Ophiostoma species, which formed a separate clade. The rDNA region of O. quercus was found to be at least as closely related to that of O. novo-ulmi and O. ulmi as it is to that of O. piceae. The implications of these results for the evolution of the Dutch elm disease fungi are discussed.

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