Paraburkholderia pallida sp. nov. and Paraburkholderia silviterrae sp. nov., isolated from forest soil.

Abstract

Two Gram-stain-negative, aerobic, motile, white-pigmented and rod-shaped bacterial strains, 7MH5T and 4 M-K11T, were isolated from forest soil of Dinghushan Biosphere Reserve, Guangdong Province, PR China. Strain 7MH5T grew at 4-37 °C (optimum, 28-33 °C), pH 3.5-9.0 (pH 4.0-5.5) and in the presence of 0-3 % (w/v) NaCl (0-1.5 w/v); while strain 4 M-K11T grew at 4-42 °C (20-33 °C), pH 3.5-8.5 (pH 4.5-6.0) and in the presence of 0-2.5 % (w/v) NaCl (0-1.5 w/v). Strains 7MH5T and 4 M-K11T have the highest 16S rRNA gene sequence similarities of 98.6 and 98.7 % to Paraburkholderia peleae PP52-1T, and 98.4 % between themselves. In the 16S rRNA gene sequence phylogram, strains 4 M-K11T and Paraburkholderia ferrariae NBRC 106233T formed a clade while 7MH5T were relatively distinct from other Paraburkholderia species. Based on the UBCG phylogenomic analysis, strains 7MH5T and 4 M-K11T formed a clade with Paraburkholderia oxyphila NBRC 105797T and Paraburkholderia sacchari LMG 19450T in the genus of Paraburkholderia. The DNA G+C contents of strains 7MH5T and 4 M-K11T were 64.2 and 64.3 %, respectively. Digital DNA-DNA hybridization and the average nucleotide identity values of strains 7MH5T, 4 M-K11T and closely related strains were in the ranges of 25.2-63.6 % and 81.0-95.5 %, respectively. The two strains had the same major respiratory quinone: ubiquinone-8. Strain 7MH5T had C16 : 0, C17 : 0cyclo, C19 : 0cyclo ω8c and summed feature 8 (C18 : 1 ω7c/C18 : 1 ω6c) as its major fatty acids, while strain 4 M-K11T had major fatty acids of C16 : 0, C17 : 0cyclo and summed feature 2 (iso-C16 : 1 I/C14 : 0-3OH). The major polar lipids were phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol. On the basis of phenotypic and phylogenetic analyses based on both 16S rRNA gene and whole genome sequences, as well as chemotaxonomic data, strains 7MH5T and 4 M-K11T represent two novel species of the genus Paraburkholderia, for which the names Paraburkholderia pallida sp. nov. (type strain 7MH5T=GDMCC 1.1450T=KACC 19962T) and Paraburkholderia silviterrae sp. nov. (type strain 4 M-K11T=GDMCC 1.1284T=CGMCC 1.15450T=KACC 19961T=LMG 29217T) are proposed.