Description of Ectothiorhodospira salini sp. nov.

Abstract

Strain JA430 T is a Gram-negative, vibrioid to spiral shaped phototrophic purple sulfur bacterium isolated from anoxic sediment of a saltern at Kanyakumari in a mineral salts medium that contained 2% NaCl (w/v). Strain JA430 T grows optimally at 5-6% NaCl and tolerates up to 12% NaCl. Intracellular photosynthetic membranes were of the lamellar type. Bacteriochlorophyll a and carotenoids of the spirilloxanthin series are present as photosynthetic pigments. Major cellular fatty acids are C 18:1 ω7c, C 16:0, C 19:0 cycloω8c and C 16:1 ω 7c/C 16:1 ω 6c. Strain JA430 T exhibits photoorganoheterotrophy and chemoorganoheterotrophy and requires para-aminobenzoic acid, pantothenate and pyridoxal phosphate for growth. Phylogenetic analysis on the basis of 16S rRNA gene sequence analysis showed that strain JA430 T forms monophyletic group in the genus Ectothiorhodospira. The highest sequence similarity for strain JA430 T was found with the type strains of Ectothiorhodospira variabilis DSM 21381 T (96.1%) and Ectothiorhodospira haloalkaliphila ATCC 51935 T (96.2%). Morphological and physiological characteristics discriminate strain JA430 T from other species of the genus Ectothiorhodospira, for which we describe this as a novel species, Ectothiorhodospira salini sp. nov. (= NBRC 105915 T = KCTC 5805 T).