Isoptericola croceus sp. nov., a novel actinobacterium isolated from saline-alkali soil.

Abstract

A novel actinomycete, designated strain q2T, was isolated from the saline-alkaline soil, collected from Daqing, Heilongjiang province, China. The results of phylogenetic analysis based on the 16S rRNA gene sequences indicated that strain q2T belongs to the genus Isoptericola, and showed the highest sequence similarity to Isoptericola halotolerans KCTC 19046T (98.48%) and Isoptericola chiayiensis KCTC 19740T (98.13%), respectively. The average nucleotide identity values between strain q2T and other members of the genus Isoptericola were lower than 95% recommended for distinguishing novel prokaryotic species. Cells of strain q2T were Gram-staining-positive, aerobic, non-motile, rod-shaped and non-spore-forming. Colonies of strain q2T were golden-yellow pigmented, tidy edged and smooth surfaced. Growth occurred at 15-37°C (optimum, 29°C), pH 7.0-10.0 (optimum, pH 8.0). The predominant respiratory quinones were MK-9(H4) and MK-9(H2). The main detected polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, and phosphatidylinositol mannoside. The peptidoglycan compositions were L-alanine, D-aspartic, L-glutamic acid and L-lysine (type A4α). The major cellular fatty acids (> 10%) were anteiso-C15:0, iso-C15:0, and anteiso-C17:0. The G+C content of the genomic DNA was determined to be 69.7%. Based on the phenotypic, physiological, genotypic, and phylogenetic data, strain q2T represents a novel species of the genus Isoptericola, for which the name Isoptericola croceus sp. nov. is proposed. The type strain is q2T (= GDMCC 1.2923T = KCTC 49759T).