Paraburkholderia acidiphila sp. nov., Paraburkholderia acidisoli sp. nov. and Burkholderia guangdongensis sp. nov., isolated from forest soil, and reclassification of Burkholderia ultramafica as Paraburkholderia ultramafica comb. nov.

Abstract

Three Gram-stain-negative, aerobic, motile and rod-shaped bacterial strains, 7Q-K02T, DHF22T and DHOM02T, were isolated from forest soil sampled at Dinghushan Biosphere Reserve, Guangdong Province, China. Strains 7Q-K02T, DHF22T and DHOM02T grew at 4-37, 4-42 and 12-37 °C, pH 3.0-8.5, 3.5-8.5 and 5.0-8.0, and in the presence of 0-3.0, 0-3.5 and 0-2.5\u200a% (w/v) NaCl; with optima at 28-33, 28 and 28-33\u2009°C, pH 3.5-6.5, 4.0-5.5 and 6.5-7.0, and 0-1.5, 0-1.5 and 0.5-1.5\u200a% (w/v) NaCl, respectively. Strains 7Q-K02T and DHF22T have the highest 16S rRNA gene sequence similarities of 99.0 and 98.0\u200a% to Paraburkholderia sacchari LMG 19450T and 97.7\u200a% between themselves, while strain DHOM02T shares the highest similarity of 98.4\u200a% to Burkholderia rinojensis A396T followed by 98.3\u200a% to Burkholderia plantarii ATCC 43733T. In the 16S rRNA gene sequence phylogram, strain 7Q-K02T formed a sister branch with Paraburkholderia sacchari, Paraburkholderia oxyphila and Paraburkholderia paradisi, and strain DHF22T was separated from all other species within the genus Paraburkholderia, while strain DHOM02T formed a separated clade with members of the genus Burkholderia. The DNA G+C contents of strains 7Q-K02T, DHF22T and DHOM02T wwe 64.3, 65.4 and 66.6\u200a%, respectively. Digital DNA-DNA hybridization (dDDH) and average nucleotide identity (ANI) values of strains 7Q-K02T, DHF22T and closely related Paraburkholderia strains were in the ranges of 25.5-43.7\u200a%\u2009and 81.5-91.3\u200a%, respectively. While dDDH and ANI values between strain DHOM02T and Burkholderia strains with genome sequence data were in the ranges of 22.4-31.0\u200a%\u2009and 78.2-86.1\u200a%, respectively. These three strains have the same major respiratory quinone: ubiquinone-8. Strains 7Q-K02T, DHF22T and DHOM02T have C16\u200a:\u200a0, C17\u200a:\u200a0 cyclo, C19\u200a:\u200a0 cyclo ω8c and summed feature 8 (C18\u200a:\u200a1 \u2009ω7c/C18\u200a:\u200a1 \u2009ω6c) as their major fatty acid compositions. The major polar lipids were phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol. On the basis of phenotypic, phylogenetic, genomic analyses and chemotaxonomic data, strains 7Q-K02T and DHF22T represent two novel species of the genus Paraburkholderia, for which the names Paraburkholderia acidiphila sp. nov. (type strain 7Q-K02T=CGMCC 1.15433T=KCTC 62472T=LMG 29209T) and Paraburkholderia acidisoli sp. nov. (type strain DHF22T=GDMCC 1.1448T=LMG 30262T) are proposed, while strain DHOM02T represents a novel species in the genus Burkholderia, for which the name Burkholderia guangdongensis sp. nov. (type strain DHOM02T=KCTC 42625T=LMG 28843T) is proposed. We also propose to transfer Burkholderia ultramafica to the genus Paraburkholderia as Paraburkholderia ultramafica comb. nov. based mainly on the results of phylogenomic analysis.