Etymology. It is named ‘maxigenoma’ due to its genome size – it has the biggest genome of any Planktophila isolates.
Brief description. Planktophila maxigenoma MRE-196 (ENA accession number GCA_965267625) was isolated from the epilimnion (0.5m depth) of Římov Reservoir, Czech Republic (date: 2021-11-01) and it is the only isolated representative of the species. It has a complete circular genome with a size of 1,500,077 bp, a GC content of 48.7%, and a coding density of 95.73%. It encodes one rRNA operon and 38 tRNA genes. It encodes for both actinorhodopsin and heliorhodopsin, as well as the capacity to de novo synthesize retinal. It encodes genes involved in pili assembly and maturation. The closest isolated species is Planktophila jirickensis JirE-27 with whom it shares an average nucleotide identity of 80.3%. Recruitment analysis showed that it is a very rare species, encountered only in the Římov Reservoir, and particularly in the hypolimnion (30m depth). The Current GTDB classification (r220) is d__Bacteria;p__Actinomycetota;c__Actinomycetia;o__Nanopelagicales; f__Nanopelagicaceae; g__Planktophila; s__.