Xenophilus arseniciresistens sp. nov., an arsenite-resistant bacterium isolated from soil

Abstract

A Gram-reaction-negative, aerobic, motile, rod-shaped, arsenite [As(III)]-resistant bacterium, designated strain YW8T, was isolated from agricultural soil. 16S rRNA gene sequence analysis showed over 97 % sequence similarity to strains of the environmental species Xenophilus azovorans , Xenophilus aerolatus , Simplicispira metamorpha , Variovorax soli , and Xylophilus ampelinus . However, the phylogenetic tree indicated that strain YW8T formed a separate clade from Xenophilus azovorans . DNA–DNA hybridization experiments showed that the DNA–DNA relatedness values between strain YW8T and its closest phylogenetic neighbours were below 24.2–35.5 %, which clearly separated the strain from these closely related species. The major cellular fatty acids of strain YW8T were C16 : 0, C 17 : 0 cyclo, C18 : 1ω7c, and summed feature 3(C16 : 1ω6c and/or C16 : 1ω7c). The genomic DNA G+C content was 69.3 mol%, and the major respiratory quinone was ubiquinone-8. The predominant polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, three unknown phospholipids, an unknown polar lipid and phosphatidylserine. The major polyamines were 2-hydroxyputrescine and putrescine. On the basis of morphological, physiological and biochemical characteristics, phylogenetic position, DNA–DNA hybridization and chemotaxonomic data, strain YW8T is considered to represent a novel species of the genus Xenophilus , for which the name Xenophilus arseniciresistens sp. nov. is proposed; the type strain is YW8T ( = CCTCC AB2012103T = KACC 16853T).