Submitted to: American Phytopathological Society Abstracts
Publication Type: Abstract only
Publication Acceptance Date: 4/1/2010
Publication Date: 6/10/2010
Citation: Carbone, I., Horn, B.W., Moore, G.G., Olarte, R.A., Worthington, C.J., Monacell, J.T., Stone, E.A. 2010. The population genomics of mycotoxin diversity in Aspergillus flavus and Aspergillus parasiticus. Phytopathology 100:S157. Interpretive Summary: None required.
Technical Abstract: Mycotoxins, and especially the aflatoxins, are an enormous problem in agriculture, with aflatoxin B1 being the most carcinogenic known natural compound. The worldwide costs associated with aflatoxin monitoring and crop losses are in the hundreds of millions of dollars. Aspergillus flavus and A. parasiticus are the most common agents of aflatoxin contamination of oil-rich seed and grain crops. In addition to aflatoxins, A. flavus produces another unrelated mycotoxin, cyclopiazonic acid (CPA). Populations of A. flavus show a high level of variation in mycotoxin production, with individuals producing both aflatoxins and CPA, aflatoxins alone, CPA alone or neither mycotoxin. We performed array-Comparative Genome Hybridization (aCGH) for multiple sexual crosses in A. flavus and A. parasiticus whereby each cross was represented as a parent-offspring trio comprising two parents and one offspring. Examination of aCGH data for each parent-offspring trio revealed that meiotic recombination is highly structured along chromosomes, with recombination hotspots in the aflatoxin, CPA and other predicted secondary metabolic gene clusters. Crossovers in the aflatoxin cluster of F1 progeny coincided with recombination hotspots observed in natural populations. Population genetic data show that a combination of ecological factors, asexual/sexual reproduction and balancing selection may influence mycotoxin diversity in these agriculturally important fungi.