info:eu-repo/semantics/conferenceProceedings All rights reserved Mycoantagonistic activity of indigenous antibiotic-producing Pseudomonas spp. against sugar beet pathogens (Fusarium spp., Macrophomina phaseolina and Rhizoctonia solani) Isolation of indigenous Pseudomonas spp. from natural disease-suppressive soils allowed the selection of beneficial strains with biocontrol and growth-promoting traits. Pseudomonas spp. are well adapted to growing in the rhizosphere and some of them possess bacterial traits and genes contributing to rhizosphere competence and the mechanisms of pathogen suppression. To select isolates with mycoantagonistic activity, 56 fluorescent Pseudomonas were isolated from five Serbian disease-suppressive soils. Using PCR, some of antibiotic production genes: phenazine-1-carb- oxylic acid (PCA), 2,4-diacetylphloroglucinol (DAPG), pyrrolnitrin (PRN) and pyoluteorin (PLT), were detected in 31 indigenous Pseudomonas isolates. Mycoantagonistic activity of antibiotic-producing isolates against sugar beet pathogens was tested in vitro on Waksman agar. All tested fungal isolates originated from sugar beet plants were collected from the main growing regions in Republic of Serbia. In pathogenicity tests, typical symptoms were recovered on leaves or roots of artificially inoculated plants, depending on a pathogen. Fusarium spp. (SR27/11 and SR7/12) were isolated from roots with symptoms of dry rot and vascular necrosis. Monohyphal isolates of Macrophomina phaseolina (62/4) and Rhizoctonia solani (SR17/12) were isolated from roots exhibiting characteristic symptoms of charcoal and Rhizoctonia root rot, respectively. The growth inhibition rate ranged from 12 to 68% for Fusarium spp., 8 to 52% for M. phaseolina and 3 to 86% for R. solani. The Pseudomonas isolate K38 showed the highest percentage (86%) of growth inhibition of R. solani. The most promising indigenous antibiotic-producing Pseudomonas isolates will further be investigated for disease suppression of sugar beet pathogenic fungi in field conditions. application/pdf 166415 bytes 2014 eng 74th IIRB Congress – 74ème Congrès de l'IIRB – 74. IIRB-Kongress, 1-3/7/2014, Dresden (D) https://unilib.phaidrabg.rs/o:3091 Jošić, Dragana Starović, Mira Stojsin, Vera Bagi, Ferenc Budakov, D. Pivić, Radmila