title: Microbial community composition affects soil fungistasis.
abstract: Most soils inhibit fungal germination and growth to a certain extent, a phenomenon known as soil fungistasis. Previous observations have implicated microorganisms as the causal agents of fungistasis, with their action mediated either by available carbon limitation (nutrient deprivation hypothesis) or production of antifungal compounds (antibiosis hypothesis). To obtain evidence for either of these hypotheses, we measured soil respiration and microbial numbers (as indicators of nutrient stress) and bacterial community composition (as an indicator of potential differences in the composition of antifungal components) during the development of fungistasis. This was done for two fungistatic dune soils in which fungistasis was initially fully or partly relieved by partial sterilization treatment or nutrient addition. Fungistasis development was measured as restriction of the ability of the fungi Chaetomium globosum, Fusarium culmorum, Fusarium oxysporum, and Trichoderma harzianum to colonize soils. Fungistasis did not always reappear after soil treatments despite intense competition for carbon, suggesting that microbial community composition is important in the development of fungistasis. Both microbial community analysis and in vitro antagonism tests indicated that the presence of pseudomonads might be essential for the development of fungistasis. Overall, the results lend support to the antibiosis hypothesis.
authors.affiliation: Department of Plant-Microorganism Interactions, Centre for Terrestrial Ecology, Netherlands Institute of Ecology, 6666 ZG Heteren, The Netherlands. w.deboer@nioo.knaw.nl
authors.forename: Wietse
authors.initials: W
authors.lastname: de Boer
authors.forename: Patrick
authors.initials: P
authors.lastname: Verheggen
authors.forename: Paulien J A
authors.initials: PJ
authors.lastname: Klein Gunnewiek
authors.forename: George A
authors.initials: GA
authors.lastname: Kowalchuk
authors.forename: Johannes A
authors.initials: JA
authors.lastname: van Veen
mesh_terms: D000898:Antibiosis; D000935:Antifungal Agents / Q000378:metabolism / Q000494:pharmacology; D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D002245:Carbon Dioxide / Q000378:metabolism; D002597:Chaetomium / Q000187:drug effects / Q000254:growth & development; D015169:Colony Count, Microbial; D017753:Ecosystem; D005658:Fungi / Q000187:drug effects / Q000254:growth & development*; D005670:Fusarium / Q000187:drug effects / Q000254:growth & development; D008969:Molecular Sequence Data; D011549:Pseudomonas / Q000254:growth & development / Q000378:metabolism; D017422:Sequence Analysis, DNA; D012987:Soil / Q000032:analysis; D012988:Soil Microbiology; D014242:Trichoderma / Q000187:drug effects / Q000254:growth & development
chemical_list: D000935:Antifungal Agents; D012987:Soil; D002245:Carbon Dioxide