Rhizosphere microflora of some citrus as a source of antagonistic actinomycetes

Qualitative distribution of microorganisms in rhizosphere soils under citrus trees (lemon and orange) was observed by the serial dilution-spread plate method. The maximally represented actinomycete genus was Streptomyces followed by Micromonospora and Nocardia. The streptomycete strains were classified in taxonomical groups by their characteristics. Several cultures produced antibacterial or antifungal antibiotics. Some of the antibiotics have been determined as beta-lactams, polyethers, nonpolyenic macrolides and azalomycin B. Other strains synthesized exoenzymes. (C) 2002 Editions scientifiques et medicales Elsevier SAS. All rights reserved.