International Diatom Annotation Jamboree and Phytoplankton Sequencing Workshop Held at DOE Joint Genome Institute Surprises Revealed


Twenty-seven scientists from the U.S. and six other countries met at the DOE Joint Genome Institute in Walnut Creek, California, on October 21-24 to annotate the newly sequenced genome of the diatom Thalassiosira pseudonana. Annotation of the genome revealed some surprises, including the presence of genes coding for compounds called siderophores that bind iron. Low iron concentrations limit the growth of phytoplankton, and thus carbon fixation, in large regions of the world’s oceans. The discovery of these genes has profound implications for our understanding of how the ocean carbon cycle is regulated. Diatoms are of primary importance to the “biological pump” of carbon in the world’s oceans. They fix carbon dioxide into their cells, then sink to the deep ocean where the carbon may be sequestered for decades or longer. Diatoms are also of keen interest to the biotechnology industry because of their ability to produce silica cell walls in highly complex patterns. A second meeting on October 25 brought together world experts in marine phytoplankton to generate a list of top candidates for future genomic sequencing. Four high priority candidates were selected, including other diatom species and a colony forming alga called Phaeocystis, that are important in ocean carbon sequestration.