Bacteria with a broad-spectrum of antagonistic activity against pathogenic fungi of cereals

Prevalent fungal pathogens of cereals in Lithuania belong to diverse systematic groups and this makes search for microbial biocontrol measures rather difficult. One of the options would be broad-spectrum biocontrol agents. In order to find these, 1037 seed-borne and 11 soil-borne rhizosphere pathogenic fungi were isolated and their systematic position determined. Fungi of genera Alternaria, Ulocladium, Fusarium were dominant, with Bipolaris sorokiniana and Drechslera being isolated at significantly lower rates. Forty two of these pathogenic micromycetes and type strain of Gaeumannomyces graminis var. graminis DSM1463 were used as test cultures in antagonistic trials involving 214 microbial isolates from agricultural soil. Ten bacterial strains were found to express antagonistic in vitro activity against more than half of the selected pathogenic fungi. 16S ribosomal deoxyribonucleic acid (rDNA) analysis showed 5 of these bacterial strains to be related to Bacillus subtilis species: 1 – B. thuringiensis, 1 – B. mycoides/B. pseudomycoides, 2 – Serratia odorifera and 1 – Pseudomonas spp.