Dyella monticola sp. nov. and Dyella psychrodurans sp. nov., isolated from monsoon evergreen broad-leaved forest soil of Dinghu Mountain, China

Abstract

Cells of bacterial strains 4 G-K06T and 4MSK11T, isolated from soil samples collected from monsoon evergreen broad-leaved forest of the Dinghushan Mountain (112° 31′ E 23° 10′ N), Guangdong Province, PR China, were Gram-stain-negative, aerobic, non-spore-forming, non-motile and rod-shaped. Strain 4 G-K06T grew at 10–37 °C, pH 3.5–7.5 and 0–3.5 % (w/v) NaCl; while 4MSK11T grew at 4–42 °C, pH 3.5–7.5 and 0–2.5 % (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences showed strain 4 G-K06T formed a clade with Dyella flagellata 4 M-K16T, Dyella acidisoli 4M-Z03T, Dyella humi DHG40T and Dyella nitratireducens DHG59T, while strain 4MSK11T formed a clade with Dyella caseinilytica DHOB09T and Dyella mobilis DHON07T, both within the genus Dyella . The result of the partial atpD, gyrB and lepA gene sequence analysis supported the conclusion based on 16S rRNA gene sequence analysis, which showed that these two strains represent two novel species of Dyella . The average nucleotide identity and digital DNA–DNA hybridization value for the whole genomes were 75.0–79.0 and 20.3–22.6 % between strains 4 G-K06T, 4MSK11T and those described Dyella species with genome sequences; while the DNA–DNA hybridization rates between strains 4 G-K06T, 4MSK11T and closely related Dyella species (without genome sequence) were 29.5–41.8 %. The major cellular fatty acids of these two strains were iso-C15 : 0, iso-C16 : 0 and iso-C17 : 1 ω9c, while the major polar lipids consisted of phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol and several unidentified phospholipids and aminophospholipids. The only ubiquinone of these two strains was ubiquinone-8. The DNA G+C contents of 4 G-K06T and 4MSK11T were 60.4 and 61.3 mol%, respectively. On the basis of the evidence presented here, strains 4 G-K06T and 4MSK11T represent two novel species of the genus Dyella , for which the names Dyella monticola sp. nov. (type strain 4 G-K06T=LMG 30268T=GDMCC 1.1188T) and Dyella psychrodurans sp. nov. (type strain 4MSK11T=KCTC 62280T=GDMCC 1.1185T) are proposed.