MSA - Systematics/Evolution
Samuels, Gary , Nalim, Ameena , Geiser, David .
The true identity of Nectria haematococca.
Nectria haematococca is usually identified as the teleomorph of Fusarium solani, a common plant pathogen and cause of opportunistic infections in animals, including man. Nectria haematococca and F. solani belong to the Fusarium solani species complex (FSSC). Nectria haematococca includes seven phylogenetically distinct mating populations and at least two ‘varieties.’ In addition, unnamed perithecial species are common in the FSSC. Perithecial morphology is conserved in the FSSC; with species differences manifested in the anamorph. What is true Nectria haematococca? It was originally described from a 19th century collection made on wood in Sri Lanka. Because there is no culture from this specimen, and no anamorph remains on the type collection, an epitype is required to stabilize taxonomy of N. haematococca. We epitypify the species and document phylogenetic and phenotypic diversity among teleomorph and anamorph collections made in Sri Lanka. The FSSC comprises three clades based to some extent on biogeographic structure. Five of the seven Sri Lankan perithecial populations cluster in Clade 2, which was formerly thought to be South American. One of these collections made near the type locality of N. haematococca is designated as epitype. Two of the perithecial strains and all of the F. solani isolates from soil samples cluster in the cosmopolitan Clade 3. Soil strains rarely clustered with ascospore-derived strains, suggesting a clonal structure inÂ the soil populations. Nectria haematococca is not the teleomorph of F. solani, a species originally isolated from potato in Europe, nor is N. haematococca a species of Nectria. It has been placed in its own genus, Haematonectria. Neocosmospora vasinfecta, the type species of Neocosmospora, is derived from within the FSSC. On nomenclatural and phylogenetic grounds, Neocosmospora should be adopted as the teleomorph name but we argue against adopting any name for the teleomorph of these Fusarium species at this time.
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1 - United States Department of Agriculture, Systematic Mycology and Microbiology Lab, Rm. 304, B-011A, 10300 Baltimore Ave., Beltsville, Maryland, 20705, USA
2 - New Mexico State University, Moecular Biology Program, Las Cruces, NM, 88003, USA
3 - Pennsylvania State University, Dept. Plant Pathology, Buckhout Lab., University Park, PA, 16802, USA
Presentation Type: Oral Paper:Papers for Topics
Location: Cottonwood A/Snowbird Center
Date: Tuesday, July 28th, 2009
Time: 2:30 PM