VIEW ARTICLE

Induction of Chlamydospore Formation in Fusarium solani by Soil Bacteria. E. J. Ford, Department of Plant Pathology, University of California, Berkeley 94720; A. H. Gold(2), and W. C. Snyder(3). (2)(3)Department of Plant Pathology, University of California, Berkeley 94720. Phytopathology 60:479-484. Accepted for publication 13 October 1969. DOI: 10.1094/Phyto-60-479.

Sterile soil extracts induced three clones of Fusarium solani f. sp. phaseoli to produce fewer chlamydospores than did nonsterile extracts or extracts preincubated prior to sterilization. Isolates of three genera of soil bacteria (Protaminobacter, Arthrobacter, and Bacillus) induced chlamydospore formation by one or more clones of the fungus in mixed cultures. Substances isolated from culture filtrates of Arthrobacter and Bacillus each induced chlamydospore formation by a different clone of the fungus under axenic conditions. Twenty-five of 50 bacterial isolates induced one clone of F. solani f. sp. phaseoli to form chlamydospores; 16 of another 50 bacterial isolates induced a second clone to form chlamydospores; and 10 of another 50 bacterial isolates induced a third clone to form chlamydospores. The hypothesis is advanced that specific bacteria are responsible for the chlamydospore-inducing substances in soil, and that changes in the numbers and types of bacteria in soil may affect the ability of specific clones of Fusarium to produce chlamydospores in that soil.