Molecular characterization of toxigenic and atoxigenic Aspergillus flavus isolates, collected from peanut fields in China.
OBJECTIVE
The objectives of this study were to assess the genetic relationships between toxigenic and atoxigenic isolates of Aspergillus flavus collected from peanut fields in China, and to analyse deletions within the aflatoxin biosynthetic gene cluster for the atoxigenic isolates.


RESULTS
Analysis of random-amplified polymorphic DNA and microsatellite-primed PCR data showed that the toxigenic and atoxigenic isolates of A. flavus were not clustered based on their regions and their ability of aflatoxin and sclerotial production. These results were further supported by DNA sequence of ITS, pksA and omtA genes. PCR assays showed that 24 of 35 isolates containing no detectable aflatoxins had the entire aflatoxin gene cluster. Eleven atoxigenic isolates had five different deletion patterns in the cluster.


CONCLUSIONS
Toxigenic and atoxigenic isolates of A. flavus are genetically similar, but some atoxigenic isolates having deletions within the aflatoxin gene cluster can be identified readily by PCR assays.


CONCLUSIONS
Because the extensive deletions within the aflatoxin gene cluster are not rare in the atoxigenic isolates, analysis of deletion within the cluster would be an effective method for the rapid screening of atoxigenic isolates for developing biocontrol agents.
Yin
Y
Y
Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Ministry of Agriculture, Zhejiang University, Hangzhou, China.
Lou
T
T
Yan
L
L
Michailides
T J
TJ
Ma
Z
Z
D000348:Aflatoxins / Q000096:biosynthesis*; D010367:Arachis / Q000382:microbiology*; D001231:Aspergillus flavus / Q000145:classification* / Q000201:enzymology / Q000235:genetics*; D002681:China; D017353:Gene Deletion; D005800:Genes, Fungal; D008969:Molecular Sequence Data; D005810:Multigene Family
D000348:Aflatoxins