Urease Characteristics and Phylogenetic Status of Bacillus paralicheniformis

Abstract

In 2015, <i>Bacillus paralicheniformis</i> was separated from <i>B. licheniformis</i> on the basis of phylogenomic and phylogenetic studies, and urease activity was reported as a phenotypic property able to differentiate between the two species. Subsequently, we have found that the urease activity of <i>B. paralicheniformis</i> is strain-specific, and does not reliably discriminate between species, as strains having the same urease gene cluster were identified in <i>B. licheniformis</i> and <i>B. sonorensis</i>, the closest relatives of <i>B. paralicheniformis</i>. We developed a multilocus sequence typing scheme using eight housekeeping genes, <i>adk, ccpA, glpF, gmk, ilvD, pur, spo0A</i>, and <i>tpi</i> to clearly identify <i>B. paralicheniformis</i> from closely related <i>Bacillus</i> species and to find a molecular marker for the rapid identification of <i>B. paralicheniformis</i>. The scheme differentiated 33 <i>B. paralicheniformis</i> strains from 90 strains formerly identified as <i>B. licheniformis</i>. Among the eight housekeeping genes, <i>spo0A</i> possesses appropriate polymorphic sites for the design of a <i>B. paralichenofomis</i>-specific PCR primer set. The primer set designed in this study perfectly separated <i>B. paralicheniformis</i> from <i>B. licheniformis</i> and <i>B. sonorensis</i>.