Dyella humicola sp. nov., Dyella subtropica sp. nov., Dyella silvatica sp. nov. and Dyella silvae sp. nov., isolated from subtropical forest soil.

Abstract

Four novel bacterial strains, designated RBB1W86T, RXD159T, RBB189T and RLT163T, were isolated from subtropical forest soil of the Nanling National Nature Reserve located in Guangdong Province, PR China. 16S rRNA gene phylogeny indicated their affiliation to the genus Dyella, among which strains RBB1W86T and RXD159T were closely related to Dyella halodurans CGMCC 1.15435T with 16S rRNA gene sequence similarities of 98.8 and 99.5 %, respectively, and strains RBB189T and RLT163T were closely related to Dyella tabacisoli CGMCC 1.16273T (98.8 %) and Dyella japonica JCM 21530T (99.4 %), respectively. Phylogenomic analysis based on 92 core genes showed consistent phylogeny with the 16S rRNA gene phylogeny for strains RBB1W86T, RBB189T and RLT163T, while strain RXD159T showed a closer relationship with D. tabacisoli CGMCC 1.16273T and strain RBB189T. The genome-derived average nucleotide identity (ANI) values between the newly isolated strains and their closely related species were 70.18‒90.20 %, and the corresponding digital DNA-DNA hybridization (dDDH) values were 20.80‒40.30 %. Meanwhile, the ANI and dDDH values between each pair of the newly isolated strains were 75.80‒79.77 % and 21.30‒23.30 %, respectively. They all took iso-C15 : 0 and summed feature 9 (10-methyl C16 : 0 and/or iso-C17 : 1 ω9c) as the major fatty acids. Moreover, C16 : 0, iso-C16 : 0, iso-C17 : 0 and summed feature 3 (C16 : 1 ω7c and/or C16 : 1 ω6c) were also variously distributed as major components. They all took ubiquinone 8 as the only predominant respiratory quinone and phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine and an unidentified phospholipid as the major polar lipids. Phosphatidylmethylethanolamine was only present in strain RBB189T as another major component. Based on the results of phenotypic, genotypic and chemotaxonomic analyses, the newly isolated strains could be clearly distinguished from their closely related species and should represent four distinct novel species of the genus Dyella, for which the names Dyella humicola sp. nov. (type strain RBB1W86T=GDMCC 1.1901T=KACC 21988T), Dyella subtropica sp. nov. (type strain RXD159T=GDMCC 1.1902T=KACC 21989T), Dyella silvatica sp. nov. (type strain RBB189T=GDMCC 1.1900T=KACC 21990 T) and Dyella silvae sp. nov. (type strain RLT163T=GDMCC 1.1916T=KACC 21991T) are proposed.