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-K02^T, DHF22^T and DHOM02^T, were isolated from forest soil sampled at Dinghushan Biosphere Reserve, Guangdong Province, China. Strains 7Q-K02^T, DHF22^T and DHOM02^T 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 % (w/v) NaCl; with optima at 28-33, 28 and 28-33 °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 % (w/v) NaCl, respectively. Strains 7Q-K02^T and DHF22^T have the highest 16S rRNA gene sequence similarities of 99.0 and 98.0 % to Paraburkholderia sacchari LMG 19450^T and 97.7 % between themselves, while strain DHOM02^T shares the highest similarity of 98.4 % to 'Burkholderia rinojensis' A396^T followed by 98.3 % to Burkholderia plantarii ATCC 43733^T. In the 16S rRNA gene sequence phylogram, strain 7Q-K02^T formed a sister branch with Paraburkholderia sacchari, Paraburkholderia oxyphila and Paraburkholderia paradisi, and strain DHF22^T was separated from all other species within the genus Paraburkholderia, while strain DHOM02^T formed a separated clade with members of the genus Burkholderia. The DNA G+C contents of strains 7Q-K02^T, DHF22^T and DHOM02^T wwe 64.3, 65.4 and 66.6 %, respectively. Digital DNA-DNA hybridization (dDDH) and average nucleotide identity (ANI) values of strains 7Q-K02^T, DHF22^T and closely related Paraburkholderia strains were in the ranges of 25.5-43.7 % and 81.5-91.3 %, respectively. While dDDH and ANI values between strain DHOM02^T and Burkholderia strains with genome sequence data were in the ranges of 22.4-31.0 % and 78.2-86.1 %, respectively. These three strains have the same major respiratory quinone: ubiquinone-8. Strains 7Q-K02^T, DHF22^T and DHOM02^T have C_{16 : 0}, C_{17 : 0} cyclo, C_{19 : 0} cyclo ω8c and summed feature 8 (C_{18 : 1} ω7c/C_{18 : 1} ω6c) 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-K02^T and DHF22^T represent two novel species of the genus Paraburkholderia, for which the names Paraburkholderia acidiphila sp. nov. (type strain 7Q-K02^T=CGMCC 1.15433^T=KCTC 62472^T=LMG 29209^T) and Paraburkholderia acidisoli sp. nov. (type strain DHF22^T=GDMCC 1.1448^T=LMG 30262^T) are proposed, while strain DHOM02^T represents a novel species in the genus Burkholderia, for which the name Burkholderia guangdongensis sp. nov. (type strain DHOM02^T=KCTC 42625^T=LMG 28843^T) 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.

Keywords: Burkholderia; Paraburkholderia; acidiphila; acidisoli; guangdongensis; phylogeny.