The Biogeography and Phylogeny of Unicellular Cyanobacterial Symbionts in Sponges from Australia and the Mediterranean

Abstract

The distribution, host associations, and phylogenetic relationships of the unicellular cyanobacterial symbionts of selected marine sponges were investigated with direct 16s rDNA sequencing. The results indicate that the symbionts of the marine sponges Aplysina aerophoba, Ircinia variabilis, and Petrosia ficiformis from the Mediterranean, four Chondrilla species from Australia and the Mediterranean, and Haliclona sp. from Australia support a diversity of symbionts comprising at least four closely related species of Synechococcus. These include the symbionts presently described as Aphanocapsa feldmannii from P. ficiformis and Chondrilla nucula. A fifth symbiont from Cymbastela marshae in Australia is an undescribed symbiont of sponges, related to Oscillatoria rosea. One symbiont, Candidatus Synechococcus spongiarum, was found in diverse sponge genera in the Mediterranean Sea and the Indian, Pacific, and Southern oceans, whereas others were apparently more restricted in host association and distribution. These results are discussed in terms of the biodiversity and biogeographic distributions of cyanobacterial symbionts.

Vertical transmission and successive location of symbiotic bacteria during embryo development and larva formation in Corticium candelabrum (Porifera: Demospongiae)

“…Moreover, cyanobacteria and heterotrophic bacteria can coexist in the same species, spread through the sponge mesohyl (e.g. Usher et al, 2004).…”

Ultrastructure, Molecular Phylogenetics, and Chlorophyll a Content of Novel Cyanobacterial Symbionts in Temperate Sponges

“…using electron microscopy, molecular characterization and 91 chlorophyll a quantification. The host sponges I. fasciculata and I. variabilis were chosen 92 due to previous reports of cyanobacterial symbionts in these species [8,47,65,66], their 93 close phylogenetic relationship [14] and their distinct zonation patterns within the littoral 94 benthos of the NW Mediterranean Sea [14]. Typical of a phototrophic sponge species, I.…”

Species of the sponge genus Chondrilla (Demospongiae: Chondrosida: Chondrillidae) in Australia

“…"Candidatus S. spongiarum" was also found in samples of Chondrilla nueula from the Ligurian Sea, with the two symbionts having 100'J:) 165 rDNA sequence similarity. This cyanobacterial species has not to date been found free-living in seawater (Usher et al 2004c). …”

“…Cyanobacteria: sponges were found to contain cyanobacteria in low concentrations with 99.8'!i) partial sequence similarity to Synechococcus WH 8103 (Genbank), a species which occurs in the water column (Usher et al 2004c). …”

“…Species of Chondrilla have been reported to have abundant populations of symbiotic bacteria in their mesohyl (Boury-Esnault 2002), and C. allstraliensis has been found to have both bacteria (Dey et al 2004) and symbiotic cyanobacteria (Usher et al 2001(Usher et al , 2004c. Cyanobacterial symbionts are thought to aid in the rapid growth of larvae at settlement (Wilkinson 1992), and to provide an advantage to adult sponges in competition with algae and other photosynthetic organisms for substrate in high light areas (Wilkinson 1983).…”