# Genome Analysis and Characterization of Formosa bonchosmolovskayae sp. nov. Isolated from Brown and Green Algae, and a Proposal to Reclassify Formosa maritima Cao et al. 2020 and Bizionia arctica Li et al. 2015 as Xanthomarina New Members

## TL;DR

Scientists discovered a new marine bacterial species, Formosa bonchosmolovskayae, and reclassified two existing species into a new genus, Xanthomarina.

## Contribution

The paper introduces a new species and proposes the reclassification of two existing species based on genomic and phenotypic data.

## Key findings

- The new species Formosa bonchosmolovskayae has a genome with high potential for degrading marine polysaccharides.
- Formosa maritima and Bizionia arctica were reclassified into the genus Xanthomarina based on genomic and phenotypic analysis.
- The genus Formosa has an open pangenome with a high proportion of carbohydrate-active enzymes.

## Abstract

Two marine bacteria, designated strains 4Alg 33Tand 3Alg 14/1, were isolated from brown (Saccharina japonica) and green (Ulva fenestrata) macroalgae, respectively. These isolates were aerobic Gram-negative rods exhibiting a gliding motility. The 16S rRNA gene phylogenetic analysis clearly showed their belonging to the genus Formosa, the family Flavobacteriaceae, and the phylum Bacteroidota. The closest relatives of the new strains were Formosa undariae KCTC 32328T (99.05%), Formosa arctica IMCC 9485T (99.05%) and Formosa agariphila KMM 3901T (98.96%). The ANI and dDDH values between the two new strains were 97.9% and 85.3%, respectively. The AAI values between 4Alg 33T and Formosa type strains ranged from 80.1% (Formosa haliotis MA1T) to 91.4% (F. undariae KCTC 32328T). The cellular fatty acid and polar lipid profiles of the new isolates were generally similar to those of the type strains of Formosa species. The genomes of 4Alg 33T and 3Alg 14/1 are represented by a circular chromosome of 4,157,724 bp and 4,316,096 bp in size with 3536 and 3879 protein-coding genes, respectively. They shared a DNA G+C content of 34.3 mol% and comprised four rrn operons. The pangenome of the genus Formosa belongs to the open type and is characterized by an abundance of CAZymes. The proportion of CAZyme genes in novel genomes was more than 5%, with a prevalence of glycoside hydrolase genes, suggesting great potential for utilizing marine-derived polysaccharides. Based on the results of polyphasic characterization, the two algal isolates represent a distinct species lineage within the genus Formosa, for which we propose the name Formosa bonchosmolovskayae sp. nov. with the type strain 4Alg 33T (= KMM 3963T = KCTC 72008T). In addition, we have proposed to transfer Formosa maritima Cao et al. 2020 and Bizionia arctica Li et al. 2015 to the genus Xanthomarina Vaidya et al. 2015 as Xanthomarina maritima comb. nov. and Xanthomarina arctica comb. nov. based on a combination of the genomic and phenotypic characteristics.