Phylogeny of
16S rRNA, Ribulose 1,5-Bisphosphate Carboxylase/Oxygenase,and
Adenosine 5'-Phosphosulfate Reductase Genes from Gammaand
Alphaproteobacterial Symbionts in Gutless Marine Worms (Oligochaeta)
from Bermuda and the Bahamas
Anna Blazejak,1 Jan Kuever,1†
Christer Erse´us,2 Rudolf Amann,1
and Nicole Dubilier1*
Max Planck Institute of Marine Microbiology, Celsiusstrasse
1, D-28359 Bremen, Germany.
Gutless oligochaetes are small marine worms
that live in obligate associations with bacterial endosymbionts.While
symbionts from several host species belonging to the
genus Olavius have been described, little is
known of the symbionts from the host genus Inanidrilus.
In this study, the diversity of bacterial endosymbionts
in Inanidrilus leukodermatus from Bermuda and
Inanidrilus makropetalos from the Bahamas was
investigated using comparative sequence analysis of
the 16S rRNA gene and fluorescence
in situ hybridization. As in all other gutless oligochaetes
examined to date, I. leukodermatus and I.
makropetalos harbor large, oval bacteria identified
as Gamma 1 symbionts. The presence
of genes coding for ribulose-1,5-bisphosphate
carboxylase/oxygenase form I (cbbL)
and adenosine 5'-phosphosulfate reductase (aprA)
supports earlier studies indicating that these symbionts
are chemoautotrophic sulfur oxidizers. Alphaproteobacteria,
previously identified only in the gutless oligochaete
Olavius loisae from the southwest Pacific Ocean, coexist
with the Gamma 1 symbionts in both
I. leukodermatus and I. makropetalos,
with the former harboring four and the latter two alphaproteobacterial
phylotypes. The presence of these symbionts in hosts
from such geographically distant oceans as the Atlantic
and Pacific suggests that symbioses with alphaproteobacterial
symbionts may be widespread in gutless oligochaetes.
The high phylogenetic diversity of bacterial endosymbionts
in two species of the genus Inanidrilus, previously
known only from members of the genus Olavius,
shows that the stable coexistence of multiple symbionts
is a common feature in gutless oligochaetes.
Keywords:16SrRNA,Phylogeny;Oceanobacillus,microorganisms;Taxonomy,
Microbes,Gutless oligochaetes,endosymbionts,Olavius,Inanidrilus,I.
leukodermatus ,I. makropetalos.
Corresponding author: Tel 49-421 2028-932;
Fax 49-421 2028-580.
E-mail: ndubilie@mpi-bremen.de |
