Trichormus variabilis FSR Genome sequencing and assembly. Trichormus variabilis FSR

Anabaena variabilis FSR is a photosynthetic, nitrogen-fixing cyanobacterium that was isolated as a possible cyanobiont from the fresh-water fern Azolla pinnata. This free-living, filamentous strain forms heterocysts in the absence of combined nitrogen and fixes nitrogen using one of three nitrogenase systems, Nif1, Nif2, or Vnf. A. variabilis FSR is chemoheterotrophic and can use sugars as a carbon source. A. variabilis FSR is nearly identical to A. variabilis ATCC 29413 (NCBI:txid240292), a free-living strain that is capable of infecting the liverwort Blasia. However, unlike A. variabilis ATCC 29413 and other similar strains, A. variabilis FSR lacks the excision element in the nifD1 gene and lacks the 37.1 kb tRNA-cys incision element.