Effects of small increases in copper levels on culturable basidiomycetous yeasts in low-nutrient soils.
OBJECTIVE
Investigating the effect of perturbations, with relatively low Cu concentrations, on yeast community composition in low-nutrient virgin soil.


RESULTS
Culturable soil yeast populations were monitored at an experimental site treated with the fungicide copper oxychloride (10 mg Cu per kg soil). Yeast numbers were unaffected by additional Cu; however, a shift in yeast community composition from Hymenomycetes to Urediniomycetes species occurred. Subsequent growth experiments conducted with a synthetic liquid medium revealed that hymenomycetous and urediniomycetous yeasts were affected differently by 1 and 10 mg l(-1) Cu. Soil microcosm experiments then indicated that additional 10 mg kg(-1) Cu may improve the competitive ability of urediniomycetous yeasts in the presence of hymenomycetous yeasts.


CONCLUSIONS
The shift from hymenomycetous to urediniomycetous yeasts, as a result of slightly increased soil Cu levels, may be because of hymenomycetous yeasts being more sensitive to elevated Cu levels and urediniomycetous yeasts having an improved competitive ability in the presence of elevated Cu levels.


CONCLUSIONS
Yeast community composition of pristine low-nutrient soils may change as a result of perturbations with relatively low concentrations of Cu. Urediniomycetous yeasts should be studied as potential bio-indicators of Cu perturbations.
Department of Microbiology, Stellenbosch University, Stellenbosch, South Africa.
J-M
JM
Vreulink
W
W
Stone
A
A
Botha
D001487:Basidiomycota / Q000187:drug effects* / Q000254:growth & development; D003300:Copper / Q000494:pharmacology*; D005659:Fungicides, Industrial / Q000494:pharmacology*; D012987:Soil; D012988:Soil Microbiology; D015003:Yeasts / Q000187:drug effects* / Q000254:growth & development
D005659:Fungicides, Industrial; D012987:Soil; C007120:copper oxychloride; D003300:Copper