Some nutritional factors affecting production of biomass and antifungal metabolites of Coniothyrium minitans
2002
McQuilken, M.P. | Gemmell, J. | Whipps, J.M.
The ability of the mycoparasite Coniothyrium minitans to utilize a range of C and N sources and vitamins for growth, pycnidial formation and antifungal metabolite production was examined using a defined liquid medium. Coniothyrium minitans was able to use all the C sources tested, with the exception of D-xylose, and all the N sources tested, although growth was generally better on organic N sources rather than NO3-N. Increasing C:N ratios from 9:1-202:1 with N constant (2.0 g L(-1) L-alanine) resulted in steadily increasing yields, whereas increasing C:N ratios with C constant (40.0 g L(-1) D-glucose) gradually decreased yield. Addition of thiamine to the glucose-alanine basal medium resulted in the greatest increase in growth but biomass was still less than that achieved using an undefined molasses yeast medium. Pycnidial production was generally low or failed to occur in the basal medium +C +N sources in the absence of vitamins, but addition of thiamine consistently led to abundant pycnidial formation. Molasses-yeast static culture provided greater biomass and conidial yields than molasses-yeast shaken culture. Incorporation of C. minitans culture medium into potato dextrose broth (10% v/v) resulted in consistent reduction in growth of Sclerotinia sclerotiorum irrespective of C, N or vitamin content of the basal medium or whether molasses-yeast medium was used. This is the first report of consistent production of antifungal metabolites by C. minitans.
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