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ARS Home » Research » Publications at this Location » Publication #138959
Title: STEMPHYLIUM SPP: NEW HOST ASSOCIATIONS AND PHYLOGENY

Author
item Oneill, Nichole
item CAMARA, MARCOS - VISITING SCIENTIST
item PALM, MARY - APHIS
item KOIKE, STEVEN - UNIV OF CA SALINAS
item VAN BERKUM, PETER - APHIS

Submitted to: International Congress of Plant Pathology Abstracts and Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 10/9/2002
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: New host associations were identified among isolates of Stemphylium that are pathogenic to alfalfa, chickpea, spinach and lettuce. Phylogenetic relationships estimated from divergence in ITS, glyceraldehyde-3-phosphate dehydrogenase (gpd), and translation elongation factor (EF-1 alpha) gene sequences, when compared with 16 described species, indicated that the isolates may represent as yet undescribed new species. Phylogenetic relationships among the described species generally agreed with their division into separate species based on variation of morphology as for example size and shape of conidia, conidiophores, and ascospores. There was strong support for monophyly of the genus Stemphylium. Analysis of the gpd fragment in particular was useful for establishing well-supported relationships among the species and isolates. Isolates from spinach or chickpea, or isolates from crops from New Zealand were distinctly grouped. Isolates from Auckland that were pathogenic to alfalfa were phylogentically distinct from two other resolved groups of isolates from alfalfa. Alfalfa pathogens Stemphylium botryosum and two isolates with morphological characters similar to S. globuliferum had identical sequences at loci but differed from isolates of S. vesicarium, S. alfalfae and S. herbarum, which were nearly identical to each other. Isolates pathogenic to chickpea and closely related to S. sarciniforme appeared in a clade characterized by species with smooth spores. Isolates from spinach were distinct within a group of species pathogenic to forage legumes.