Fungal Interference with<i>Aspergillus flavus</i>Infection and Aflatoxin Contamination of Maize Grown in a Controlled Environment

Wicklow, Donald T.; Horn, Bruce W.; Shotwell, Odette L.; Hesseltine, C. W.; Caldwell, R. W.

doi:10.1094/phyto-78-68

Cited by 71 publications

(34 citation statements)

References 6 publications

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“…Several fungi can interfere with aflatoxin production on artificial media or other sterile substrates (9,13,16). However, the biocontrol potential of those fungi tested in developing corn, grown under controlled conditions, is inadequate in preventing aflatoxin production by A. flavus (18). Greenhouse experiments verified the biocontrol potential of atoxigenic A. j7avus strains on cotton (7).…”

Section: Discussionmentioning

confidence: 99%

Reduction in Aflatoxin Content of Maize by Atoxigenic Strains of Aspergillus flavus

Brown

Cotty

Cleveland

1991

Journal of Food Protection

147

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In field plot experiments, an atoxigenic strain of Aspergillus flavus interfered with preharvest aflatoxin contamination of corn when applied either simultaneously with or one day prior to a toxigenic strain. The atoxigenic strain reduced preharvest aflatoxin contamination 80 to 95%. The atoxigenic strain was also effective in reducing postharvest aflatoxin contamination caused by both an introduckd toxigenic strain and by strains resident on the kernels. The results suggest that atoxigenic strains of A.flavus may have potential use as biological control agents directed at reducing both preharvest and postharvest aflatoxin contamination of corn.Aflatoxins, toxic metabolites of the fungi Aspergillus jlavus Link: Fr. and A. parasiticus Speare, are potent carcinogens which pose serious health hazards to humans and domestic animals because they frequently contaminate agricultural commodities (4,8). Corn grown in the southeastern United States is more frequently colonized by high populations of A. flavus than corn grown in the Midwest, where most U.S. corn is grown (19). However, the drought of 1988 created favorable conditions for A. j7avus in the Midwest, and the Wall Street Journal (February 23, 1989) reported one-third of the crop tested in Iowa and Illinois contained dangerous levels of aflatoxin. This, according to the article, caused greatly increased concern in the U.S. corn industry.Biological control of several plant diseases has been demonstrated by utilizing certain strains of the causal organism (12,14,15,20). Strains of A. flavus that do not produce aflatoxins have been selected from fungal populations in cotton and corn fields (6,17). In greenhouse tests, atoxigenic strains of A.flavus significantly reduced production of aflatoxin B, in cottonseed coinoculated during development with toxigenic strains (7). When atoxigenic strains were introduced into wounded cotton bolls one day prior to the toxigenic strain, even greater control of aflatoxin was obtained (7). This study provided useful information but was camed out in a controlled environment. In the field, where A. j7avus first associates with the crop, greater biological and environmental complexities exist. Also, it is not known if atoxigenic strains influence contamination of harvested crops which already possess complex microflora and may be previously infected with A. flaws (10). In the present study, an atoxigenic strain, previously identified and shown effective in greenhouse tests on cottonseed, was tested for efficacy on corn under field and storage conditions. A preliminary presentation of these studies has been made (3). MATERIALS AND METHODS F~rngal strains and growth conditionsStrains of A. flavus utilized in this study were isolated from agricultural soil and cottonseed in Arizona (6,7). Strain 13 produced large quantities of aflatoxins both in culture and in developing cottonseed. while strain 36 did not produce detectable levels (

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Section: Discussionmentioning

confidence: 99%

Reduction in Aflatoxin Content of Maize by Atoxigenic Strains of Aspergillus flavus

Brown

Cotty

Cleveland

1991

Journal of Food Protection

147

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“…The results of this study support the hypothesis that previous contamination of foods and feed by other molds can influence aflatoxin production, as previously observed by other authors. Fungal interference with A. jlavus and aflatoxin contamination by "competing fungi" in maize has been observed (4). Mislivec e t a l .…”

Section: Resultsmentioning

confidence: 99%

Effect of ochratoxin A on aflatoxin production by Aspergillus parasiticus

Serafini¹,

Foddai²,

Pieretti³

et al. 1991

Can. J. Bot.

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“…In the present study, section Nigri also co-occurred with section Flavi species on peanut seeds but was less inhibitory than competing section Flavi species toward the colonization of seeds by section Flavi species. Aspergillus niger has been shown to inhibit aflatoxin production under laboratory conditions (Wicklow et al 1980;Horn and Wicklow 1983) and in cultivated corn and peanuts (Hill et al 1983;Wicklow et al 1988a). However, the application of large numbers of A. niger conidia to droughtstressed peanuts for biological control fails to reduce aflatoxins (Dorner 2004).…”

Section: Discussionmentioning

confidence: 99%

Relationship between soil densities ofAspergillusspecies and colonization of wounded peanut seeds

Horn

2006

Can. J. Microbiol.

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Soil is a reservoir for Aspergillus flavus and A. parasiticus, fungi that commonly colonize peanut seeds and produce carcinogenic aflatoxins. Densities of these fungi in soil vary greatly among fields and may influence the severity of peanut infection. This study examined the relationship between soil density of Aspergillus species and the incidence of peanut seed colonization under laboratory conditions. Viable peanut seeds were wounded and inoculated with 20 soils differing in composition and density of Aspergillus species and were then incubated for 14 days at 37 degrees C (seed water activity = 0.92). The effect of soil density of individual section Flavi species (A. flavus strains L and S, A. parasiticus, A. caelatus, and A. tamarii), section Nigri, and A. terreus on the incidence of seed colonization was best expressed as a function of exponential rise to maximum. Exponential curves often rose to maximum percentages of seed colonization by section Flavi species that were well below 100% despite high species densities in some soils. Competition primarily among section Flavi species may explain the reduced incidences of seed colonization. An average of two or fewer propagules of each Aspergillus species in the soil at the wound site was required for colonization of 20% of peanut seeds. Other fungal species were capable of invading peanut seeds only when soil densities of sections Flavi and Nigri species were low.

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Fungal Interference withAspergillus flavusInfection and Aflatoxin Contamination of Maize Grown in a Controlled Environment

Cited by 71 publications

References 6 publications

Reduction in Aflatoxin Content of Maize by Atoxigenic Strains of Aspergillus flavus

Reduction in Aflatoxin Content of Maize by Atoxigenic Strains of Aspergillus flavus

Effect of ochratoxin A on aflatoxin production by Aspergillus parasiticus

Relationship between soil densities ofAspergillusspecies and colonization of wounded peanut seeds

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