Translocation and persistence of antibiotics produced by Bacillus and Streptomyces spp. in the bean plant. African Crop Science Conference Proceedings

Abstract

Antibiotic culture filtrates produced by Bacillus (CA5) and Streptomyces spp. were tested for translocation and persistence when applied on snap beans inoculated with rust (Uromyces appendiculatus). The antibiotics were applied on the first trifoliolate leaves and translocation was assessed as the number of rust pustules on non-treated leaflets or trifoliolates, while persistence was assessed as the number of rust pustules on rust infected plants at different times after antibiotic treatment. The treatments were replicated three times, each replicate consisting of pots containing three plants. Antibiotics from both Bacillus and Streptomyces were found to have up to 100% trans-lamina and leaflet-to-leaflet translocation but no significant trifoliate-to-trifoliate translocation. Moreover, the antibiotic culture filtrates controlled rust infection for up to 10 days after application on the bean plant. However, no rust control was found on the plants after 16 days. The study indicated that the antibiotics produced by antagonistic Bacillus and Streptomyces species possess systemic activity that can persist for slightly over one week. These metabolites are potential bean rust control products and could be incorporated in integrated disease management programs for high value horticultural crops.