Emphasis Type="Italic"Verminephrobacter aporrect

Authors: Marie B Lund Sarah Schätzle Andreas Schramm Kasper U Kjeldsen

Publish Date: 2011/10/22

Volume: 101, Issue: 3, Pages: 507-514

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Abstract

Clone librarybased studies have shown that almost all lumbricid earthworm species harbour hostspecific 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 rodshaped nonendosporeforming 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 573 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 At4T = DSM 21361T = LMG 25313T and V aporrectodeae subsp caliginosae type strain Ac9T = DSM 21895T = LMG 25312T isolated from the nephridia of the earthworms Aporrectodea tuberculata and A caliginosa respectivelyWe thank Tove Wiegers and Britta Poulsen for excellent technical assistance and Rikke Louise Meyer for help with processing oxygen micro profiles This study was financially supported by the Danish Research Council for Natural Sciences grant 21040410 to AS and postdoctoral fellowship grant 27205313 to KUK

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