VIEW ARTICLE

Production of Antifungal Substances Active Against Rhizoctonia solani in Chitin-Amended Soil. B. Sneh, Assistant, Department of Plant Pathology and Microbiology, Faculty of Agriculture, The Hebrew University of Jerusalem, Rehovot, Israel; Y. Henis, Associate Professor, Department of Plant Pathology and Microbiology, Faculty of Agriculture, The Hebrew University of Jerusalem, Rehovot, Israel. Phytopathology 62:595-600. Accepted for publication 31 December 1971. DOI: 10.1094/Phyto-62-595.

A correlation between inhibition of saprophytic activity of Rhizoctonia solani in chitin-amended soil and the increase in antifungal activity of n-butanol soil extracts as compared to nonamended soil was observed. In addition to R. solani, extracts of chitin-amended soil inhibited the growth of 17 other species of fungi; two species of Fusarium were not affected. Addition of active soil extracts resulted in inhibition of saprophytic activity of R. solani in natural but not in autoclaved soil. Multiplication of Saccharomyces cerevisiae, a polyene-sensitive organism, was not more inhibited in a chitin-amended than in a nonamended soil, suggesting that polyenes are not the active agents. The antifungal factors in the n-butanol extract of chitin-amended soil were separated by thin-layer chromatography into 23 ethanol-soluble active fractions. Active fractions were also obtained from ethanol extracts of bacteria, streptomycetes, and fungi isolated from chitin-amended soil and from nonamended check soil. On separation, the active substances behaved like polar lipids but their phosphorus content (0.05 to 0.7%) was much lower than that of phospholipids. It is postulated that the active factors may be nonspecific cell constituents of microbial origin.