Submitted to: Mycological Society of America
Publication Type: Abstract Only
Publication Acceptance Date: 8/1/2006
Publication Date: 8/1/2006
Citation: Inderbitzin, P., Shoemaker, R.A., Oneill, N.R., Turgeon, B.G., Berbee, M.L. Systematics and mating systems of fungal pathogens of opium poppy: crivellia papaveracea with a brachycladium penicillatum asexual state and a homothallic species b. papaveris. Mycological Society of America.
Technical Abstract: The systematics of the fungal opium poppy pathogens formerly known as Pleospora papaveracea, along with allied asexual states formerly placed in Dendryphion, is revised based on analysis of phylogenetic relationships, comparative morphology, and analysis of mating systems. Using morphology, 18S and ITS rDNA, we established that these species belong to the Alternaria group rather than to Pleospora. We erect the new genus Crivellia, with Crivellia papaveracea as type. ITS rDNA analyses suggested with moderate support A. brassicicola, A. japonica and Ulocladium alternariae as Crivellia's closest relatives. Combined ITS, partial GPD and EF-1 alpha analyses confirmed earlier studies showing that asexual isolates in the Crivellia lineage of poppy pathogens represent two closely-related species. Because Dendryphion was determined to be polyphyletic, the former genus Brachycladium was resurrected for B. penicillatum and for B. papaveris, the Crivellia asexual states that had been in Dendryphion. The mycelia from single conidium or single ascospore isolates from C. papaveracea either have a MAT1-1 or MAT1-2 gene and are thus heterothallic. In contrast, each single-conidium isolate of B. papaveris has an incomplete MAT1-2 gene fused to a MAT1-1 region and is inferred to be homothallic. We speculate that ancestral MAT fusion might have led to speciation in Crivellia.