title: Verminephrobacter aporrectodeae sp. nov. subsp. tuberculatae and subsp. caliginosae, the specific nephridial symbionts of the earthworms Aporrectodea tuberculata and A. caliginosa.
abstract: Clone library-based studies have shown that almost all lumbricid earthworm species harbour host-specific symbiotic bacteria belonging to the novel genus Verminephrobacter in their nephridia (excretory organs). To date the only described representative from this genus is Verminephrobacter eiseniae, the specific symbiont of the earthworm Eisenia fetida. In this study two novel rod-shaped, non-endosporeforming, betaproteobacterial symbionts were isolated from the nephridia of two closely related earthworm species. Both isolates were affiliated with the genus Verminephrobacter by 16S rRNA gene sequence analysis. Similarly to V. eiseniae, the two isolates grew aerobically with a preference for low oxygen concentrations on a range of sugars, fatty acids and amino acids and fermentatively on glucose and pyruvate. These phenotypes match well with the conditions reported or inferred for the nephridial environment. Based on 16S rRNA gene similarity, DNA-DNA hybridization value and phenotypic characteristics the two isolates are clearly distinct from V. eiseniae. Phenotypic characteristics could not clearly differentiate the two strains as separate species but a low DNA-DNA hybridization value of 57.3%, their earthworm host specificity, differing temperature ranges and pH optima suggest that they represent two subspecies of a novel species of Verminephrobacter. For this species, the name V. aporrectodeae sp. nov. is proposed, with the two subspecies V. aporrectodeae subsp. tuberculatae (type strain, At4(T) = DSM 21361(T) = LMG 25313(T)) and V. aporrectodeae subsp. caliginosae (type strain, Ac9(T) = DSM 21895(T) = LMG 25312(T)) isolated from the nephridia of the earthworms Aporrectodea tuberculata and A. caliginosa, respectively.
authors: Department of Bioscience, Microbiology, Aarhus University, Ny Munkegade 114, Aarhus C, Denmark. mlund@stanford.edu
authors: Marie B
authors: MB
authors: Lund
authors: Sarah
authors: S
authors: Schätzle
authors: Andreas
authors: A
authors: Schramm
authors: Kasper U
authors: KU
authors: Kjeldsen
mesh_terms: D000825:Animal Structures / Q000382:microbiology; D000818:Animals; D042621:Comamonadaceae / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D004269:DNA, Bacterial / Q000235:genetics; D004275:DNA, Ribosomal / Q000235:genetics; D005838:Genotype; D008969:Molecular Sequence Data; D009835:Oligochaeta / Q000382:microbiology*; D010641:Phenotype; D010802:Phylogeny; D012329:RNA, Bacterial / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D021521:Ribotyping; D012689:Sequence Homology, Nucleic Acid; D013045:Species Specificity; D013559:Symbiosis
chemical_list: D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S