Taxonomy of registered Bacillus spp. strains used as plant pathogen antagonists

Strains of Bacillus spp. are one of the most important classes of bacterial biocontrol agents, which are commonly used and commercialized as plant pathogen antagonists and plant growth promoters. In the United States, there are currently 14 strains of Bacillus sp. registered as plant pathogen crop protection products. Recent advances in sequencing technology have led to many taxonomic revisions in the Bacillus subtilis group, which encompasses many of these strains. Recent studies have identified a few strains that were registered with different species nomenclature than they are currently recognized. The current study determined that taxonomic position of each of these strains and the results show most were registered under species nomenclature that is inconsistent with their current taxonomy. In addition, the current study identified selective primers to identify Bacillus velezensis, which was the most commonly misidentified strain in the study. This study should help establish a link between the research literature and product labels, which should lead to improved knowledge and regulatory actions.