Antagonistic activity of cellulolytic bacteria — destroyers of organic matter against phytopathogenic micromycetes

Abstract

Goal. To investigate the ability of active strains of cellulolytic bacteria to exhibit antagonistic activity against phytopathogenic micromycetes. Methods. To determine the antifungal activity of bacteria, the microbiological method of countercultures on a nutrient medium was used. Results. The ability of active strains of cellulolytic bacteria Bacillus sp. 6488, Bacillus sp. 6605, Microbacterium sp. 6633, Microbacterium sp. 6634, Pseudomonas sp. 6650, Bacillus sp. 6658, Paenibacillus polymyxa KB to show antagonistic activity against the test cultures of phytopathogenic micromycetes Fusarium culmorum Sacc. 50716, Alternaria alternate (Fries) Keissl. 2857, Nigrospora oryzae Berk. 3000 and Nigrospora oryzae Berk. 5000 (from the collection of the Department of Physiology and Systematics of Micromycetes of the D.K. Zabolotny Institute of Microbiology and Virology of NAS of Ukraine). It was established that active strains of cellulolytic bacteria suppress the development of F. sulmorum 50716, the causative agent of fusarial kernel rot of corn, as well as mitosporous fungi A. alternate 2857, N. oryzae 3000, and N. oryzae 5000, which are causative agents of nigrosporosis. The highest level of micromycete growth inhibition is characteristic for Bacillus sp.6658. The zone of mycelium lysis of F. sulmorum, N. oryzae 3000 and N. oryzae 5000 was 1.2±0.2 cm, 1.4±0.1 cm, and 1.7±0.1 cm, respectively. Bacteria Bacillus sp. 6658 completely suppressed the growth of the phytopathogenic micromycete A. alternate, the bacterium P. polymyxa KB — the development of F. sulmorum 50716 and mitosporous fungi. A. alternate 2857, N. oryzae 3000 and N. oryzae 5000, P. polymyxa KB inhibited the growth of F. sulmorum 50716 by 82.4%, A. alternate 2857 — by 67.0%, N. oryzae 3000 — by 81, 6%, and N. oryzae 5000 — by 77.6%. Conclusions. Cellulolytic bacteria Bacillus sp. 6658 and P. polymyxa KB can show high antifungal activity against phytopathogenic micromycetes F. culmorum Sacc. 50716, A. alternate (Fries) Keissl. 2857, N. oryzae Berk. 3000, and N. oryzae Berk. 5000. These microorganisms are promising for the development of a microbial preparation — a bio-destructor designed to optimize mineralization and immobilization using by-products of crop production.