Effect of intraspecific competition by Aspergillus flavus on aflatoxin formation in suspended disc culture*

Wicklow, D.T. and Bobell, J.R. and Palmquist, D.E. (2003) Effect of intraspecific competition by Aspergillus flavus on aflatoxin formation in suspended disc culture*. Mycological Research, 107 (5). pp. 617-623.

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The ability of two non-aflatoxin producing strains of Aspergillus flavus to interfere with aflatoxin production by a toxigenic A. flavus strain was examined using a replacement series with suspended disc culture method. Individual glass fiber discs, affixed to a pin suspended from the caps of scintillation vials, were inoculated with medium containing A. flavus conidial mixtures in different proportions (aflatoxin producer:non-producer=100:0, 80:20, 60:40, 20:80 and 0:100 by vol) at a constant total density (1r105 spores mlx1). Reductions in the total conidial density of these strains when grown alone, had little effect on fungal growth (mycelium dry weight) or aflatoxin production. Significant (P<0.0001) reductions in aflatoxin B1 were recorded when non-toxigenic strains represented any proportion of the inoculum mixture. Aflatoxin yield values were less than (P<0.0001) expected from the input ratios for toxigenic vs. non-toxigenic conidial inoculum within the replacement series. Aflatoxin yields were also reduced (P<0.001), with a corresponding increase in fungal growth (P<0.001), when conidia from aflatoxin producing strains were mixed in equal proportions. This suggests that the substantial inhibition of aflatoxin yield for inoculum mixtures results from the failure of spore germlings to establish a cooperative mycelial network.

Item Type: Article
Uncontrolled Keywords: Aspergillus Flavus, Aflatoxin
Author Affiliation: USDA Agricultural Research Service, National Center for Agricultural Utilization Research, 1815 North University Street,Peoria, IL 61604, USA.
Subjects: Plant Protection > Pesticides
Divisions: General
Depositing User: Mr Siva Shankar
Date Deposited: 04 Oct 2012 09:52
Last Modified: 04 Oct 2012 09:52
Official URL: http://dx.doi.org/10.1017/S0953756203007792
URI: http://eprints.icrisat.ac.in/id/eprint/8245

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