Nereida ignava gen. nov., sp. nov., a novel aerobic marine α-proteobacterium that is closely related to uncultured Prionitis (alga) gall symbionts

Abstract

A Gram-negative, slightly halophilic, non-pigmented, strictly aerobic, chemo-organotrophic bacterium was isolated from Mediterranean sea water off the Spanish coast near Valencia. This strain was poorly reactive, being unable to grow in most carbon sources analysed in minimal medium. However, good growth was observed when more complex media and longer incubation times were used. Phylogenetic analysis based on an almost complete 16S rRNA gene sequence placed strain 2SM4T within the Roseobacter group, in the vicinity of uncultured bacteria described as gall symbionts of several species of the red alga Prionitis. Sequence similarity values between strain 2SM4T and the closest neighbouring species were below 95·0 %. The cellular fatty acid composition of the Mediterranean strain confirmed its position within the ‘Alphaproteobacteria’, sharing 18 : 1ω7c as the major cellular fatty acid. The phylogenetic distance from any taxon with a validly published name and also a number of distinguishing features support the designation of strain 2SM4T as representing a novel genus and species, for which the name Nereida ignava gen. nov., sp. nov. is proposed. The type strain is 2SM4T (=CECT 5292T=DSM 16309T=CIP 108404T=CCUG 49433T).