Sequence variability of the pattern recognition receptor Mermaid mediates specificity of marine nematode symbioses

Autor(en)
Silvia Bulgheresi , Harald Gruber-Vodicka , Niels Robert Heindl , Ulrich Dirks , Maria Kostadinova , Heimo Breiteneder , Jörg Ott
Abstrakt

Selection of a specific microbial partner by the host is an all-important process. It guarantees the persistence of highly specific symbioses throughout host generations. The cuticle of the marine nematode Laxus oneistus is covered by a single phylotype of sulfur-oxidizing bacteria. They are embedded in a layer of host-secreted mucus containing the mannose-binding protein Mermaid. This Ca 2-dependent lectin mediates symbiont aggregation and attachment to the nematode. Here, we show that Stilbonema majuma symbiotic nematode co-occurring with L. oneistus in shallow water sedimentis covered by bacteria phylogenetically distinct to those covering L. oneistus. Mermaid cDNA analysis revealed extensive protein sequence variability in both the nematode species. We expressed three recombinant Mermaid isoforms, which based on the structural predictions display the most different carbohydrate recognition domains (CRDs). We show that the three CRDs (DNT, DDA and GDA types) possess different affinities for L. oneistus and S. majum symbionts. In particular, the GDA type, exclusively expressed by S. majum, displays highest agglutination activity towards its symbionts and lowest towards its L. oneistus symbionts. Moreover, incubation of L. oneistus in the GDA type does not result in complete symbiont detachment, whereas incubation in the other types does. This indicates that the presence of particular Mermaid isoforms on the nematode surface has a role in the attachment of specific symbionts. This is the first report of the functional role of sequence variability in a microbe-associated molecular patterns receptor in a beneficial association.

Organisation(en)
Department für Ökogenomik und Systembiologie , Department für Limnologie und Bio-Ozeanographie
Journal
The ISME Journal: multidisciplinary journal of microbial ecology
Band
5
Seiten
986-998
ISSN
1751-7362
DOI
https://doi.org/10.1038/ismej.2010.198
Publikationsdatum
2011
Publikationsstatus
Veröffentlicht
Peer-reviewed
Ja
ÖFOS 2012
106014 Genomik
Link zum Portal
https://ucris.univie.ac.at/portal/de/publications/sequence-variability-of-the-pattern-recognition-receptor-mermaid-mediates-specificity-of-marine-nematode-symbioses(8800b936-b91d-463d-b42b-28e589ff8ddd).html