Two psychrotolerant facultative anaerobes, strains B7-2T and B5T, were isolated from the Zoige Wetland on the Qinghai-Tibetan Plateau. The 16S rRNA gene sequences of strains B7-2T and B5T shared high similarity (>99 %) with those of the type strains of the genus Trichococcus, while their digital DNA-DNA hybridization values with each other (49 %) and with the reference type strains (48-23 %) were lower than 70 %, which suggest that they represent two novel species of the genus Trichococcus. Cells of strains B7-2T and B5T were immotile cocci, grew in the temperature range of 4-37 °C (optimum 25 °C) and were alkaliphilic with optimum growth at pH 9.0. The major components of the cellular fatty acids were C16 : 0, anteiso-C17 : 0 and C18 : 0 for strain B7-2T, and C16 : 0, anteiso-C17 : 0, C18 : 1ω9c and C18 : 0 for strain B5T. The genomic DNA G+C contents were 46.0 and 46.7 mol% for strains B7-2T and B5T, respectively. Based on physiological and genomic characteristics, it is suggested that strains B7-2T and B5T represent two novel species within the genus Trichococcus, for which the names Trichococcus paludicola sp. nov. and Trichococcus alkaliphilus sp. nov. are proposed. The type strains are B7-2T (=DSM 104691T=KCTC 33886T) and B5T (=DSM 104692T=KCTC 33885T), respectively.
Keywords: Qinghai-Tibetan Plateau; Trichococcus alkaliphilus; Trichococcus paludicola; alkalophiles; genomic analysis; wetland soil.