ARS | Publication request: DNA FINGERPRINTING ANALYSIS OF VEGETATIVE COMPATIBILITY GROUPS IN ASPERGILLUS CAELATUS

Submitted to: Mycologia
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 1, 2004
Publication Date: April 1, 2005
Citation: McAlpin, C.E., Horn, B.W., Wicklow, D.T. 2005. DNA fingerprinting analysis of vegetative compatibility groups in aspergillus caelatus. Mycologia. 97(1):70-76.

Interpretive Summary: The recently described species Aspergillus caelatus does not produce aflatoxins or cyclopiazonic acid and is recognized as a potential competitor of related aflatoxin-producing molds that infect peanuts. There is a need to determine which genotypes are most prevalent in crop fields and thereby offer the greatest potential as agents of biocontrol. The pAF28 DNA probe developed in our laboratory provides a reliable means of elucidating the population genetics of Aspergillus flavus through DNA fingerprinting. Results showed that this probe can also be used to distinguish among isolates of A. caelatus from genetically distinct populations. Furthermore, isolates belonging to the same genotype dominated A. caelatus populations from a Georgia peanut field and a tea plantation in Japan. Increased knowledge of the population biology of A. caelatus will contribute to better management of aflatoxin problems in agricultural systems.

Technical Abstract: Forty-three isolates of Aspergillus caelatus whose vegetative compatibility groups (VGCs) have been identified were assessed by DNA fingerprinting using a repetitive sequence DNA probe pAF28 cloned from A. flavus. Thirteen distinct DNA fingerprint groups or genotypes were identified among the 43 isolates. Twenty-four isolates belonging to VCG 1 produced identical DNA fingerprints and included isolates from the United States and Japan. Four other DNA fingerprint groups had multiple isolates sharing identical fingerprints corresponding to VCGs 2, 3, 12 and 13. Eight of the 13 fingerprint groups corresponding to VCGs 4-11 were represented by a single isolate with a unique fingerprint pattern. These results provide further confirmation that the pAF28 probe can distinguish VCGs of species within Aspergillus section Flavi based on DNA fingerprint patterns and that the probe can be used for estimating the number of VCGs in a sample population. Most of the A. caelatus isolates produced fewer restriction fragments and weakly hybridized with the repetitive DNA probe pAF28 compared to hybridization patterns obtained with A. flavus, suggesting less homology of the probe to A. caelatus genomic DNA.