Familial Reclassification Within Order Lysobacterales and Proposal of Four Novel Species

The order <i>Lysobacterales</i> consists of three families (<i>Rhodanobacteraceae</i>, <i>Lysobacteraceae</i> and <i>Marinicellaceae</i>), many members of which are important pathogenic and beneficial bacteria. Previous classifications of members within order <i>Lysobacterales</i> have relied heavily on 16S rRNA gene sequences, leading to taxonomic ambiguities at the familial level. With the advancement of sequencing technologies, an increasing number of whole-genome sequences have been available, providing an opportunity to revisit the taxonomy of families in <i>Lysobacterales</i>. In this study, we revisited the taxonomy of <i>Lysobacterales</i> by focusing on family-level reclassification based on phylogenomic frameworks. A total of 218 genome sequences, including 217 strains from <i>Lysobacterales</i> and 1 from <i>Nevskiales</i> (used as an outgroup), were collected for phylogenetic analysis. Phylogenetic relationships were inferred based on UBCG (up-to-date bacterial core gene) approach using 92 core genes and a concatenated protein phylogeney based on 227 single-copy orthologous proteins. Additionally, genomic similarity metrics, including average nucleotide identity (ANI), digital DNA-DNA hybridization (dDDH), average amino acid identity (AAI) and core-proteome average amino acid identity (cpAAI), were employed to assess the taxonomy of order <i>Lysobacterales</i>. Our results support the proposal of one novel family and the reassignment of six genera across different families within <i>Lysobacterales</i>, emphasizing the need for a refined family-level taxonomy. In addition, four novel species belonging to the family <i>Lysobacteraceae</i> were also confirmed. This study provides an updated familial framework for <i>Lysobacterales</i>, laying a robust foundation for future detailed taxonomic revisions at the genus and species levels.