Journal of Applied Microbiology (2004) 96, 965-972

A. Nesci, M. Etcheverry and N. Magan (2004)
Osmotic and matric potential effects on growth, sugar alcohol and sugar accumulation by Aspergillus section Flavi strains from Argentina
Journal of Applied Microbiology 96 (5), 965-972
Abstract: Aims: The effect of osmotic and matric potential stress on growth and sugar alcohols (polyols: glycerol, erythritol, arabitol and mannitol) and sugars (trehalose and glucose) accumulation in toxigenic and nontoxigenic colonies of Aspergillus flavus and A. parasiticus was evaluated.
Methods and Results: Growth of Aspergillus section Flavi with significant reductions at 20 and 30°C was more sensitive to changes in matric potential, between 60 and 100% in the range of -7 to -14 MPa. No significant differences were found between toxigenic and nontoxigenic strains for both species. Total polyol accumulation in unamended maize meal agar medium (-0.75 MPa water potential) was higher at 30 than 20°C. The major change in concentrations of endogenous sugars and total polyols was in matrically amended medium (with PEG 8000) at -7 and -10 MPa. Accumulation of glucose, arabitol, mannitol and erythritol content of A. flavus and A. parasiticus mycelial colonies was greater in normal unstressed maize meal agar medium (-0.75 Mpa) at 20°C. This was modified by solute and matric stress.
Conclusions: The data showed relative sensitivity to osmotic and matric potential, and temperature, and the impact on growth rates, polyol and sugar accumulation in mycelia of A. flavus and A. parasiticus.
Significance and Impact of the Study: The matric potential effects on growth may be of particular importance for growth and survival in environments with low-matric potential stress. The tolerance of spoilage fungi such as Aspergillus section Flavi to such modifications could increase the potential for spoilage and mycotoxin production in such substrates. This knowledge is important for understanding the relative ecological fitness of these aflatoxigenic species and in the development of prevention strategies for their control.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Miriam G. Etcheverry, Naresh Magan

Research topic(s) for pests/diseases/weeds:
rearing/culturing/mass production
molecular biology - genes

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Aspergillus flavus (plant/storage disease)
	Aspergillus parasiticus