In vitro experimental environments lacking or containing soil disparately affect competition experiments of Aspergillus flavus and co-occurring fungi in maize grains.
In vitro experimental environments are used to study interactions between microorganisms, and to predict dynamics in natural ecosystems. This study highlights that experimental in vitro environments should be selected to match closely 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 were 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 (25 and 30°C). Competition experiments showed interaction between the main effects of aflatoxin accumulation and the environment at 25°C, but not so at 30°C. However, competition experiments showed fungal populations were always interacting with their environments. Fungal survival differed after the 72-h 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°C. 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.
a Queensland Alliance for Agriculture and Food Innovation , University of Queensland , Brisbane , QLD , Australia.
Titilayo D O
TD
Falade
b School of Chemistry and Molecular Biosciences , University of Queensland , Brisbane , QLD , Australia.
Sharifah H
SH
Syed Mohdhamdan
a Queensland Alliance for Agriculture and Food Innovation , University of Queensland , Brisbane , QLD , Australia.
Yasmina
Y
Sultanbawa
a Queensland Alliance for Agriculture and Food Innovation , University of Queensland , Brisbane , QLD , Australia.
Mary T
MT
Fletcher
a Queensland Alliance for Agriculture and Food Innovation , University of Queensland , Brisbane , QLD , Australia.|c Biosciences Eastern and Central Africa , International Livestock Research Institute Hub , Nairobi , Kenya.
Jagger J W
JJ
Harvey
d Department of Agriculture , Fisheries and Forestry , Brisbane , QLD , Australia.
Mridusmita
M
Chaliha
a Queensland Alliance for Agriculture and Food Innovation , University of Queensland , Brisbane , QLD , Australia.
Glen P
GP
Fox
D000348:Aflatoxins / Q000032:analysis*; D000898:Antibiosis; D001231:Aspergillus flavus / Q000737:chemistry* / Q000254:growth & development / Q000472:pathogenicity; D032561:Cotton Fiber; D002523:Edible Grain / Q000737:chemistry / Q000382:microbiology*; D037341:Fumonisins / Q000032:analysis*; D005670:Fusarium / Q000737:chemistry / Q000254:growth & development / Q000472:pathogenicity; D009183:Mycotoxins / Q000032:analysis*; D010407:Penicillium / Q000737:chemistry / Q000254:growth & development / Q000472:pathogenicity; D012987:Soil / Q000737:chemistry; D012988:Soil Microbiology; D013696:Temperature; D014867:Water / Q000737:chemistry; D014871:Water Microbiology; D003313:Zea mays / Q000737:chemistry / Q000382:microbiology*
D000348:Aflatoxins; D037341:Fumonisins; D009183:Mycotoxins; D012987:Soil; D014867:Water
Aspergillus; Fusarium; Penicillium; Sarocladium; aflatoxin; competition; in vitro; soil