Complete genome sequencing of newly isolated thermotolerant Corynebacterium glutamicum N24 provides a new insights into its thermotolerant phenotype

To understand the genetic background of thermotolerance, we determined the complete genome sequence of a thermotolerant Corynebacterium glutamicum N24 strain isolated from soil. The whole genome based phylogenetic analysis between N24 and other related species revealed that N24 diverged from other C. glutamicum strains at earlier stages. Comparisons of thermotolerance between N24 and its related species showed that N24 and Corynebacterium efficiens YS-314 have a higher thermotolerance than Corynebacterium callunae DSM 20147 and C. glutamicum KY9002. In order to understand the link between a particular genetic background and thermotolerance, we compared the genomes of these four strains by mapping their genomes onto the N24 chromosome. We then determined the genes that were conserved in the thermotolerant species. Our results indicated the specific presence of glutathione-dependent aldehyde dehydrogenase, two sortase homologs, and lipid synthesis-related genes in the genomes of thermotolerant strains, YS-314 and N24. Therefore, these genes may be responsible for the differences in their thermotolerant phenotypes.