title: Speciation and biosynthetic variation in four dictyoceratid sponges and their cyanobacterial symbiont, Oscillatoria spongeliae.
abstract: Four species of marine sponges (Phylum Porifera, Order Dictyoceratida), which contain the filamentous cyanobacterial symbiont Oscillatoria spongeliae, were collected from four locations in Palau. The halogenated natural products associated with the symbiont were characterized from each sample, revealing that each species contained either chlorinated peptides, brominated diphenyl ethers, or no halogenated compounds. Analysis of the host sponges and the symbionts indicated that each species of sponge contained a distinct strain of morphologically similar cyanobacteria. Although cospeciation may be present in this group, we have identified that at least one host switching event has occurred in this symbiosis. Only the strain of O. spongeliae in the sponge containing the chlorinated compounds possessed genes involved in the biosynthesis of chlorinated leucine precursors, indicating that the chemical variation observed in these animals has a genetic foundation.
authors.affiliation: Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California at San Diego, La Jolla, California 92093, USA.
authors.forename: Christian P
authors.initials: CP
authors.lastname: Ridley
authors.forename: Patricia R
authors.initials: PR
authors.lastname: Bergquist
authors.forename: Mary Kay
authors.initials: MK
authors.lastname: Harper
authors.forename: D John
authors.initials: DJ
authors.lastname: Faulkner
authors.forename: John N A
authors.initials: JN
authors.lastname: Hooper
authors.forename: Margo G
authors.initials: MG
authors.lastname: Haygood
mesh_terms: D000818:Animals; D000458:Cyanobacteria / Q000378:metabolism*; D047088:Dysidea / Q000378:metabolism* / Q000382:microbiology*; D019029:Palau; D010802:Phylogeny; D013045:Species Specificity; D013559:Symbiosis / Q000502:physiology*