Genomic and phenotypic insights into Pseudocolwellia antarctica sp. nov., a novel psychrotolerant bacterium with symbiotic potential from Antarctic zooplankton

Description

Min Kyo Kim and four colleagues described in 2026 a new cold-tolerant bacterium from Antarctic zooplankton, the tiny animals that host rich microbial communities in the Southern Ocean. Two Gram-negative strains, HL-MZ7T and HL-MZ19, were characterised through combined methods, since polar microbes help drive nutrient cycles yet remain poorly mapped. Phylogenetic analysis placed both strains in the genus Pseudocolwellia, as a sister group to Pseudocolwellia agarivorans.

Complete genomes of 4.5 and 4.6 million base pairs, with guanine-cytosine contents near 36 percent, confirmed a distinct species, at only 79.5 percent average nucleotide identity with its closest relative. Gene analysis revealed tools for cold survival and for living with a host, including clusters for aryl polyenes and signalling molecules, plus genes for surface attachment and nutrient uptake. The strains grow best at 15 to 20 degrees Celsius in salty water. The authors propose the name Pseudocolwellia antarctica for this symbiotic polar resident.

Catalog record

Source: https://europepmc.org/articles/PMC13473541