Genomes of N2-fixing endosymbionts of unicellular eukaryotes and host-independence

Within the limits of genome analysis, some of the Rhopalodian endosymbionts appear to be metabolically independent of their hosts, except for requiring a carbon source. However, the choice of carbon source and the likely means of nitrogen export are not compatible with crop plants. Genetic modification would surely be necessary for any prospect of propagation of an endosymbiont in a plant of agricultural importance, and significant questions must first be answered in the laboratory. To this end, the endosymbiont of Epithemia clementina may be best suited for such investigations, eventually after transfer to the model diatom Phaeodactyllum tricornutum.