Thalassospira australica sp. nov. isolated from sea water.

Abstract

Two Gram-negative, non-pigmented, motile bacteria were isolated from a sea water sample collected at St. Kilda Beach, Port Philip Bay, Victoria, Australia. The two strains were found to grow between 4 and 40°C, pH 5-10 and tolerate up to 10% NaCl. A phylogenetic study, based on a 16S rRNA gene sequence analysis indicated that strains NP 3b2(T) and H 94 belong to the genus Thalassospira. The sequence similarity of the 16S rRNA gene between the two new isolates is 99.8% and between these strains and all validly named Thalassospira species was found to be in the range of 95-99.4%. The DNA-DNA relatedness between the two strains was found to be 80.2%, while relatedness with other validly named species of the genus Thalassospira was between 53 and 65%. The average nucleotide identity (ANI) and the in silico genome-to-genome distance (GGD) between the two bacteria and T. profundimaris WP0211(T), T. xiamenensis M-5(T), 'T. permensis' NBRC 106175(T) and T. lucentensis QMT2(T) was 76-82% and 21-25%, respectively. The results of phylogenetic and genomic analysis, together with physiological and biochemical properties, indicated that the two strains represent a new species of the genus Thalassospira. Based on these data, a new species, Thalassospira australica, is proposed with strain NP 3b2(T) (=KMM 6365(T)=JCM 31222(T)) as the type strain.