Bacillus velezensis as a model for plant-associated beneficial bacilli

The Bacillus strain GB03, the first representative of a group of plant growth-promoting rhizobacteria, now designated Bacillus velezensis, was isolated as Bacillus subtilis A13 around 50 years ago from a wheat field in Australia. With the advent of genome sequencing, FZB42, another example of the same taxonomic group of plant-associated gram-positive bacteria, was sequenced in 2007. FZB42 and other B. velezensis strains devote a much higher proportion of their whole genomic capacity than the model B. subtilis to the synthesis of secondary metabolites with antimicrobial action. This review summarizes the history of discovery and agricultural use, as well as the impressive accumulation of our knowledge base about the mutualistic interactions of B. velezensis with plants obtained during the last two decades.