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In vitro experimental environments lacking or containing soil disparately affect competition experiments of Aspergillus flavus and co-occurring fungi in maize grains

Falade, Titilayo D.O. and Syed MohdHamdan, Sharifah H. and Sultanbawa, Yasmina and Fletcher, Mary T. and Harvey, Jagger J.W. and Chaliha, Mridusmita and Fox, Glen P. (2016) In vitro experimental environments lacking or containing soil disparately affect competition experiments of Aspergillus flavus and co-occurring fungi in maize grains. Food Additives & Contaminants: Part A . ISSN 1944-0049

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Article Link(s): http://dx.doi.org/10.1080/19440049.2016.1198048

Abstract

In vitro experimental environments are used to study interactions between microorganisms, and predict dynamics in natural ecosystems. This study highlights that experimental in vitro environments should be selected to closely match the natural environment of interest during in vitro studies to strengthen extrapolations about aflatoxin production by Aspergillus and competing organisms. Fungal competition and aflatoxin accumulation was studied in soil, cotton wool or tube (water-only) environments, for Aspergillus flavus competition with Penicillium purpurogenum, Fusarium oxysporum or Sarocladium zeae within maize grains. Inoculated grains were incubated in each environment at two temperature regimes (25oC and 30oC). Competition experiments showed interaction between main effects of aflatoxin accumulation and environment at 25oC, but not so at 30oC. However, competition experiments showed fungal populations were always interacting with their environments. Fungal survival differed after the 72-hour incubation in different experimental environments. Whereas, all fungi incubated within the soil environment survived; in the cotton-wool environment, none of the competitors of A. flavus survived at 30 oC. With aflatoxin accumulation, F. oxysporum was the only fungus able to interdict aflatoxin production at both temperatures. This occurred only in the soil environment and fumonisins accumulated instead. Smallholder farmers in developing countries face serious mycotoxin contamination of their grains, and soil is a natural reservoir for the associated fungal propagules, and a drying and storage surface for grains on these farms. Studying fungal dynamics in the soil environment and other environments in vitro can provide insights into aflatoxin accumulation post harvest.

Item Type:Article
Business groups:Crop and Food Science
Keywords:Aspergillus, Fusarium, Penicillium, Sarocladium, aflatoxin, competition, soil, in vitro air exposure
Subjects:Plant culture > Harvesting, curing, storage
Plant culture > Field crops > Grain. Cereals
Plant culture > Field crops > Corn. Maize
Plant pests and diseases
Deposited On:09 Jun 2016 01:47
Last Modified:09 Jun 2016 01:47

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