Halorussus halobius sp. nov., Halorussus marinus sp. nov. and Halorussus pelagicus sp. nov., isolated from salted brown alga Laminaria

Abstract Four halophilic archaeal strains, designated HD8-83T, LYG-36T, DLLS-82 and RC-68T, were isolated from the salted brown alga Laminaria of three different origins (Dalian, Lianyungang, Dalian and Rongcheng) in China. All strains had pleomorphic rod cells that were motile, lysed in distilled water, stained Gram-negative and formed red-pigmented colonies on agar plate, except DLLS-82 showing white colonies. Based on phylogenetic analyses of the 16S rRNA genes, strain HD8-83T was closely related to Halorussus litoreus HD8-51T (97.9 % similarity), strain LYG-36T and DLLS-82 were closely related to Halorussus rarus TBN4T (94.4 % and 94.7 % similarities, respectively), and strain RC-68T exhibit close to Halorussus salinus YJ-37-HT (96.9 % similarity). Phylogenetic analyses based on rpoB′ gene and 728 concatenated single-copy orthologous clusters also show these strains formed three different branches and clustered tightly with the Halorussus members. The ANI, AAI and isDDH values between strain LYG-36T and DLLS-82 were 98.9 %, 98 % and 92.4 %, showing they were different strains of same species. While those values between isolates and other Halorussus members with values below 84.7 %, 82.9 % and 28.9 %. Based on the phenotypic, chemotaxonomic and phylogenetic properties, the strains HD8-83T, LYG-36T, DLLS-82 and RC-68T represent three novel species of the genus Halorussus for which the names Halorussus halobius sp. nov. (type strain HD8-83T = CGMCC 1.15334T = JCM 31110T), Halorussus marinus sp. nov. (type strain LYG-36T = CGMCC 1.13606T = JCM 32952T, reference strain DLLS-82 = CGMCC 1.13604 = JCM 32951) and Halorussus pelagicus sp. nov. (type strain RC-68T = CGMCC 1.13609T = JCM 32953T) are proposed.