Pusillimonas Maritima sp. nov., isolated from surface seawater

Abstract

Two Gram-stain-negative, short rod-shaped and non-flagellated strains, designated 17-4AT and L52-1-41, were isolated from the surface seawater of the Indian Ocean and South China Sea, respectively. The 16S rRNA genes of the two strains shared sequence similarity of 99.45 %. Strain 17-4AT shared the highest 16S rRNA gene similarity of 98.02 % with Pusillimonas caeni EBR-8-1T, followed by Pusillimonas noertemannii BN9T (97.47%), Pusillimonas soli MJ07T (96.93%), Parapusillimonas granuli Ch07T (96.68%), Pusillimonas ginsengisoli DCY25T (96.65%), Eoetvoesia caeni PB3-7BT (96.63%), Paracandidimonas caeni 24T (96.34%), Castellaniella defragrans 54PinT (96.28%) and Pusillimonas harenae B201T (96.05%). L52-1-41 shared the highest 16S rRNA gene similarity of 97.74 % with Pusillimonas caeni EBR-8-1T, followed by Pusillimonas noertemannii BN9T (97.47%), Pusillimonas soli MJ07T (96.65%), Parapusillimonas granuli Ch07T (96.41%), Pusillimonas ginsengisoli DCY25T (96.37%), Eoetvoesia caeni PB3-7BT (96.35%), Pusillimonas harenae B201T (96.28%), and Paracandidimonas caeni 24T (96.06%). The results of phylogenetic analyses indicated that 17-4AT and L52-1-41 formed a stable, distinct and highly supported lineage affiliated to the genus Pusillimonas. The results of the digital DNA–DNA hybridization (dDDH) and average nucleotide identity (ANI) analyses indicated that they represented a single species. They featured similar genomic DNA G+C contents of 53.2–53.4 mol%. Activities of catalase and oxidase were negative for both strains. The fatty acids patterns of 17-4AT and L52-1-41 were most similar, mostly comprised of C16: 0, C17: 0cyclo, C18: 0, C18: 1ω9c and summed feature 8 (C18: 1ω7c and/or C18: 1 ω6c). The major polar lipids of the two strains were phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol and unidentified aminolipids. The respiratory quinone of the two strains was Q-8. Hence, on the basis of the phenotypic, chemotaxonomic and genotypic data presented in this study, we proposed the classification of both strains as representatives of a novel species named Pusillimonas maritima sp. nov., with the type strain 17-4AT (=MCCC 1A12670T=KCTC 62121T=NBRC 113794T), and another strain L52-1-41 (=MCCC 1A05046=KCTC 52313).