Bacterial Associations - Pfiesteria Dinoflagellates

Co-existing with dinoflagellates are bacterial assemblages that interact with the dinoflagellates and may affect their physiology and toxigenesis. Who are these bacteria? We have discovered a diverse group of over 30 bacterial species co-existing in laboratory cultures of Pfiesteria piscicida and related dinoflagellates. The composition of the bacterial community in these cultures is similar to prokaryotic communities found associated with other harmful algal species observed in the environment, with a key component taxonomically similar to the alpha-3 subgroup, comprising the Roseobacter clade, of the marine alpha-Proteobacteria group. We are currently focusing this and other species that appear to be involved in the dinoflagellate's physiology. Our hypothesis is that some of these bacteria are endosymbiotically associated with Pfiesteria.