Submitted to: Book Chapter
Publication Type: Book / chapter
Publication Acceptance Date: 10/3/2005
Publication Date: 3/15/2006
Citation: Hua, S.T., Mcalpin, C.E., Ly, S.B. 2006. Population of aspergillus flavus on pistachio buds and flowers. In: Mendez-Vilas, A., editor. Modern Multidisciplinary Applied Microbiology: Exploiting Microbes and Their Interactions. Weinheim, Germany:Wiley-VCH Verlag. p.440-445. Interpretive Summary: California is the major state of pistachio production in US. Analysis of A. flavus population in pistachio orchard will provide information on biocontrol strategies to reduce aflatoxin in the edible nuts to meet the mandatory levels of 2-4ppb. Isolates of Aspergillus flavus from pistachio orchard were analyzed for aflatoxins production, morphoty and vegetative competitive groups (VCG). All the s-type isolates produced aflatoxin. The percentage of sclerotium-producing isolates from California orchard was much lower than those reported by others. About 50% of the isolates do not produce aflatoxin. The result gives further evidence that DNA fingerprinting using the repetitive DNA probe pAF28 could predict with 90% accuracy the VCG diversity of A. flavus population
Technical Abstract: Aspergillus flavus Link is an economically important fungus which produces carcinogenic compounds known as aflatoxins in agricultural crops such as corn, peanuts, cotton and tree nuts. The fungus has no known sexual stage; consequently, most studies on its genetic variability have been evaluated mainly by characterizing isolates based on vegetative compatibility. Complementary nitrate-nonutilizing (nit) mutants are commonly used to identify compatible isolates. This study was conducted to determine for the first time the VCGs of A. flavus isolates from a California pistachio orchard. Sclerotium size, aflatoxin production and VCGs were analyzed in order to estimate the diversity of the sample population. A better understanding of the population structures of A. flavus will faciliate the development of effective biocontrol strategies.