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

Two Gram-stain negative, aerobic and rod-shaped bacterial strains, DHOD12(T) and 7GSK02(T), were isolated from forest soil of Dinghushan Biosphere Reserve, Guangdong Province, PR China. Strain DHOD12(T) grew at 4-42 degrees C (optimum, 28-33 degrees 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 7GSK02(T) grew at 12-42 degrees C (optimum, 28-33 degrees 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 DHOD12(T) and 7GSK02(T) had the highest 16S rRNA sequence similarities of 98.0 and 98.3% with the same species Trinickia mobilis DHG64(T), 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 DHOD12(T) and 7GSK02(T) formed a clade with T. mobilis DHG64(T) that was a sister of a cluster containing the remainder of the Trinickia species. The DNA G+C contents of strains DHOD12(T) and 7GSK02(T) were 63.1 and 64.6mol%, respectively. Digital DNA-DNA hybridization and average nucleotide identity values of strains DHOD12(T), 7GSK02(T) 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 C-16:0, C-17:0 cyclo and summed feature 8 (C-18:1 omega 7c/C-18:1 omega 6c) 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 DHOD12(T) and 7GSK02(T) represent two novel species of the genus Trinickia, for which the names Trinickia violacea sp. nov. (type strain DHOD12(T)=LMG 30258(T)=CGMCC 1.15436(T)) and Trinickia terrae sp. nov. (type strain 7GSK02(T)=CGMCC 1.15432(T)=KCTC 62468(T)) are proposed.