Trinickia violacea sp. nov. and Trinickia terrae sp. nov., isolated from forest soil

Abstract

Two Gram-stain negative, aerobic and rod-shaped bacterial strains, DHOD12T and 7GSK02T, were isolated from forest soil of Dinghushan Biosphere Reserve, Guangdong Province, PR China. Strain DHOD12T grew at 4–42 °C (optimum, 28–33 °C), pH 4.0–8.5 (optimum, pH 5.5–6.5) and in the presence of 0–1.5 % (w/v; optimum, 0–0.5 %)NaCl; while strain 7GSK02T grew at 12–42 °C (optimum, 28–33 °C), pH 4.0–8.5 (optimum, pH 5.0–6.0) and in the presence of 0–0.5 % (w/v; optimum, 0 %) NaCl. Strains DHOD12T and 7GSK02T had the highest 16S rRNA sequence similarities of 98.0 and 98.3 % with the same species Trinickia mobilis DHG64T, respectively, and 98.4 % between themselves. In the 16S rRNA phylogeny, they formed a clade that was sister to a major cluster consisting of all described Trinickia species. Phylogenomic analyses with the UBCG and PhyloPhlAn methods consistently showed that strains DHOD12T and 7GSK02T formed a clade with T. mobilis DHG64T that was a sister of a cluster containing the remainder of the Trinickia species. The DNA G+C contents of strains DHOD12T and 7GSK02T were 63.1 and 64.6 mol%, respectively. Digital DNA–DNA hybridization and average nucleotide identity values of strains DHOD12T, 7GSK02T and their closely related strains were in the ranges of 21.6–31.4 % and 77.1–86.9 %, respectively. These two strains had the same major respiratory quinone, ubiquinone-8, and both had C16 : 0, C17 : 0 cyclo and summed feature 8 (C18 : 1  ω7c/C18 : 1  ω6c) as their major fatty acids. Their major polar lipids were phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol. Genomic analysis indicated that the two strains could have the potential to degrade aromatic compounds like other Trinickia species. On the basis of phenotypic and phylogenetic results, strains DHOD12T and 7GSK02T represent two novel species of the genus Trinickia , for which the names Trinickia violacea sp. nov. (type strain DHOD12T=LMG 30258T=CGMCC 1.15436T) and Trinickia terrae sp. nov. (type strain 7GSK02T=CGMCC 1.15432T=KCTC 62468T) are proposed.