VIEW ARTICLE

Ecology and Epidemiology

Partial Characterization of Volatile Fungistatic Compound(s) from Soil. J. A. Liebman, Department of Environmental Science, Policy, and Management, University of California, Berkeley 94720; L. Epstein, Department of Environmental Science, Policy, and Management, University of California, Berkeley 94720. Phytopathology 84:442-446. Accepted for publication 5 February 1994. Copyright 1994 The American Phytopathological Society. DOI: 10.1094/Phyto-84-442.

Many soils contain volatile, water-soluble compound(s) that inhibit germination of Cochliobolus victoriae conidia in the absence of a carbon source. The volatile fungistatic compound(s) from soil were separated into a cell-free extract. Loss of fungistatic activity from the extract was time- and temperature-dependent; all activity was lost within 5 min at 90 C, 48 h at 21 C, and 5 days at –70 C. Much of the fungistatic activity was lost after the soil extract was diluted by 10%, incubated in an uncapped vial, or transferred to a new vial via a gas-tight syringe. Fungistatic activity was not detected in material collected from soil into a liquid N₂ cold trap. Agarose blocks adjusted to pH 5.5–8.0 became fungistatic when incubated on soil, suggesting that the fungistatic compound(s) were relatively unaffected by hydrogen ion concentrations in this range. Carbon monoxide (CO), carbon dioxide (CO₂), nitric oxide (NO), nitrogen dioxide (NO₂), sulfur dioxide (SO₂), ammonia (NH₃), ethylene (C₂H₄), and reduced concentrations of oxygen (O₂) apparently were not responsible for fungistasis of C. victoriae conidia in soil because these compounds were not fungistatic at concentrations detected in soil.