Two Gram-stain-negative, aerobic, non-spore forming and rod-shaped bacterial strains, designated DHOM06T and 7MK8-2T, were isolated from forest soil sampled at Dinghushan Biosphere Reserve, Guangdong Province, PR China. Strain DHOM06T grew at 12-37 °C (optimum, 28-33 °C), pH 4.5-7.5 (pH 5.5) and in the presence of 0-0.5 % NaCl (w/v); while strain 7MK8-2T grew at 12-42 °C (28-33 °C), pH 4.0-8.5 (pH 4.5-5.5) and in the presence of 0-1.0 % NaCl (w/v). Strains DHOM06T and 7MK8-2T each has a 16S rRNA gene sequence similarity of 97.1-98.9 % as well as 97.4-97.9 % to Trinickia strains, respectively. In the 16S rRNA gene sequence phylogram, both strains and all five currently described Trinickia species formed a clade but they were all distinct from each other. The average nucleotide identity and digital DNA-DNA hybridization values for strains DHOM06T and 7MK8-2T and all Trinickia species were in the range of 77.4-82.6 % and 21.7-26.2 %, respectively. The DNA G+C content of DHOM06T and 7MK8-2T was 63.2 and 63.5 mol%, respectively, based on total genome calculations. These two strains contained ubiquinone 8 as the major respiratory quinone and C16 : 0, C17 : 0cyclo, C19 : 0cyclo ω8c, summed feature 3 (C16 : 1ω7c/C16 : 1ω6c) and summed feature 8 (C18 : 1ω7c/C18 : 1ω6c) as the major cellular fatty acids. The major polar lipids of DHOM06T and 7MK8-2T were phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol. On the basis of phenotypic, chemotaxonomic, phylogenetic and genomic analysis data, strains DHOM06T and 7MK8-2T represent two novel species of the genus Trinickia, for which the names Trinickia dinghuensis sp. nov. (type strain DHOM06T=GDMCC 1.1280T=LMG 30259T) and Trinickia fusca sp. nov. (type strain 7MK8-2T=GDMCC 1.1449T=KCTC 62469T) are proposed.
Keywords: Trinickia; phylogeny; proteobateria; taxonomy.