Submitted to: American Phytopathological Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 6/1/2010
Publication Date: 6/10/2010
Citation: Monacell, J.T., Horn, B.W., Singh, R., Stone, E.A., Carbone, I. 2010. Identifying heterokaryon incompatibility loci in Aspergillus flavus and Aspergillus parasiticus using array-Comparative Genome Hybridization (aCGH). Phytopathology 100:S85. Interpretive Summary: None requireed.
Technical Abstract: Heterokaryon incompatibility is the inability of two strains to undergo fusion of vegetative fungal cells. This vegetative compatibility system is dictated by a series of heterokaryon incompatibility (het) loci whose alleles must all be identical for stable hyphal fusions to occur. Het loci have been identified in several filamentous fungi, but are currently unknown in Aspergillus flavus and A. parasiticus. These species are agriculturally important plant pathogens that produce the potent carcinogens, aflatoxins. Fungal individuals can be grouped into vegetative compatibility groups (VCGs) based on their ability to undergo hyphal fusions and potentially form heterokaryons. We performed aCGH for eleven VCGs and a total of 51 strains in Aspergillus section Flavi, including A. flavus, A. parasiticus, A. oryzae, A. caelatus, A. tamarii and A. nomius. We conducted an initial screening of these data for signatures of balancing selection around single-feature polymorphism markers on chromosomes 2, 3, 4, and 6, which associated one-to-one with VCG. Our screening for evidence of balancing selection has revealed several putative het loci showing distinct patterns of trans-speciation, which is typical of other loci under balancing selection in these fungi, such as mating-type genes and the aflatoxin gene cluster. Among the candidate het loci we identified using aCGH was a previously annotated putative het locus on chromosome 2.