Trichormus variabilis PNB Genome sequencing and assembly. Trichormus variabilis PNB

Anabaena sp. PNB 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. Anabaena sp. PNB is chemoheterotrophic and can use sugars as a carbon source. Anabaena sp. PNB is nearly identical to Anabaena variabilis ATCC 29413 (NCBI:txid240292), a free-living strain that is capable of infecting the liverwort Blasia. However, unlike A. variabilis ATCC 29413, Anabaena sp. PNB lacks the 15 kb tRNA-cys incision element.