Phylogenomic description of three novel species of the Microbulbifer genus, phylum Pseudomonadota, isolated from marine sponges and corals.

Understudied bacterial genera present a dynamic phylogenetic landscape and opportunities for discovering new taxa as more strains are isolated and genomic data is added. Here, through phylogenomic analysis, we describe three novel species of the globally distributed cosmopolitan marine bacterial genus Microbulbifer. This genus is ubiquitous in marine microbiomes and is a validated source of biodegradation enzymes as well as high value small molecule natural products. Average nucleotide identity (ANI) to the closest known species, Microbulbifer variabilis ATCC 700307T, was less than 88.4% for all three novel species. Isolates of the three novel species, designated as PAAF003Ts (T = type genome), ZKSA006Ts, and SSSA003Ts were imaged to reveal their morphological characteristics. Based on phylogenetic data, strains PAAF003Ts, ZKSA006Ts, and SSSA003Ts represent three new species of the genus Microbulbifer, for which the names Microbulbifer maximicatervae sp. nov., Microbulbifer regidiadema sp. nov., and Microbulbifer mixtoriginis sp. nov. are proposed, respectively, under the SeqCode. We also reconstructed a robust phylogeny of available Microbulbifer genomes, which should facilitate future isolation and strain description studies.