FP6 priority

1.1.6   Sustainable Development, Global Change and Ecosystems

1.6.3

Title of the proposal

Diversity of yeasts and yeast-like organisms in agricultural soil – their activity and survival

Institute

Slovak Academy of Sciences, Culture Collection of Yeasts, Institute of Chemistry
Dubravska cesta 9, 842 38 Bratislava, Slovak Republic

Contact

Research subject for a potential FP6 project

The submitted project regards to soil yeasts. Its purpose is to study the community of yeast orga-nisms in agricultural soil and to compare it with the diversity of species isolated from forest and untilled soils, and to determine the influence of soil environment of this kind on the incidence of yeasts and their quantity. We will study at the dominant yeast species their killer activity, degree of tolerance towards used pesticides, and the difference in the tolerance towards stress conditions induced by increased concentration of Cd²⁺ and Ni²⁺ ions and compare the formation and structure of extracellular yeast glycoproteins produced by yeasts in the presence of these metals, which can have the different physiological influences.

The most important ecological role of yeasts in soil is decomposition of organic matter from the simplest sugars and amino acids to the most resistant polymers such as lignin and complex of soil humic acids. The major limiting factors for yeast microorganisms in soil are temperature and water content. Common management practices that may impact yeast diversity include tillage, fertilizer, and pesticides regimes and cropping rotations. Fertilizer input to soils cause an accumulation of potentially toxic elements such as heavy metals, which can also reduce yeast diversity. Microorganisms are far more sensitive to heavy metal stress than soil animals or plants growing on the same soils.

Recent international cooperation of the research team

Proposer´s relevant publications related to the research subject

1. E. Slavikova and R. Vadkertiova
Seasonal occurrence of yeasts and yeast-like organisms in the river Danube.
Antonie van Leeuwenhoek, 72 (1997) 77-80.

2. E. Slavikova and R. Vadkertiova
The occurrence of yeasts in the forest soils.
J. Basic Microbiol. 40 (2000) 207-212.

3. E. Slavikova and B. Kosikova
Modification of lignin by Geotrichum klebahnii.
World J. Microbiol. And Biotechnol. 17 (2001) 1-3.

4. E. Breierova, M. Kacurakova, and E. Stratilova
The effect of higher concentration of NaCl in the cultivation medium on changes in the composition of extracellular yeast glycoproteins.System. Appl. Microbiol. 20 (1997) 348-355.