VIEW ARTICLE

Techniques

Bacteriocin Production and Semiselective Medium for Detection, Isolation, and Quantification of Pseudomonas solanacearum in Soil. Wen -Yen Chen, Graduate research assistant, Department of Plant Pathology, North Carolina State University, Raleigh 27650; Eddie Echandi, professor, Department of Plant Pathology, North Carolina State University, Raleigh 27650. Phytopathology 72:310-313. Accepted for publication 18 June 1981. Copyright 1982 The American Phytopathological Society. DOI: 10.1094/Phyto-72-310.

A bacteriocin technique was developed to detect, isolate, and quantify Pseudomonas solanacearum in soil. Tetrazolium chloride agar, incorporated with chloramphenicol (10 μg/ml) and pentachloronitroben-zene (37.5 μg/ml), was used as a basal medium. Wide-spectrum bacteriocin-sensitive strains 159, 209, and 217 of P. solanacearum were used as indicators. Plates containing the medium were dried, spread with soil suspension, overlaid with 1.5% water agar, and incubated for 24–28 hr before being overlaid with 0.7% water agar containing the bacteriocin indicator strain. Colonies of P. solanacearum, identified by clear inhibition zones, were isolated 24 hr later. This technique was sensitive to 4.2 × 10³ colony-forming units per gram of oven-dried soil, and the efficiency of recovery of P. solanacearum from soil at 4.2 × 10⁴ colony-forming units per gram of oven-dried soil ranged from 92.0 to 100%.