Genome Sequence of “Candidatus Frankia datiscae ” Dg1, the

Members of the noncultured clade of Frankia enter into root nodule symbioses with actinorhizal species from the orders Cucurbitales and Rosales. We report the genome sequence of a member of this clade originally from Pakistan but obtained from root nodules of the American plant Datisca glomerata without isolation in culture. Frankia strains are filamentous, sporulating, aerobic actino-bacteria that induce nitrogen-fixing root nodules on about 220 plant species from eight families in three orders, Fagales, Ro-sales, and Cucurbitales. Phylogenetic analyses place symbiotic Frankia strains into three distinct clusters (7). Genomes of two members of cluster I have been sequenced, Frankia alni strain ACN14a (7.50 Mbp; GenBank accession number NC_008278) and the Casuarina-infective Frankia sp. strain HFPCcI3 (5.43 Mbp; GenBank accession number NC_007777). Three ge-nomes of cluster III representatives have been sequenced, in-cluding Frankia sp. strains EAN1pec (8.9 Mbp; GenBank ac-cession number NC_009921), EUN1f (9.35 Mbp; GenBan