Genotyping-driven diversity assessment of biocontrol potent Bacillus spp. strain collection as a potential method for the development of strain-specific biomarkers.

Bacillus species are among the most researched and frequently applied biocontrol agents. To estimate their potential as environmentally friendly microbial-based products, reliable and rapid plant colonization monitoring methods are essential. We evaluated repetitive element-based (rep) and Random Amplified Polymorphic DNA (RAPD) PCR (Polymerase Chain Reaction) genotyping in a diversity assessment of 251 strains from bulk soil, straw, and manure samples across Serbia, highlighting their discriminative force and the presence of unique bands. RAPD 272, OPG 5, and (GTG)5 primers were most potent in revealing the high diversity of a sizable environmental Bacillus spp. collection. RAPD 272 also amplified a unique band for a proven biocontrol strain, opening the possibility of Sequence Characterized Amplified Region (SCAR) marker design. That will enable colonization studies using the SCAR marker for its specific detection. This study provides a guide for primer selection for diversity and monitoring studies of environmental Bacillus spp. isolates.