Genome sequence of freshwater nontoxigenic Limnoraphis associated with microcystin-producing blooms.

• The complete genome of Limnoraphis sp. WA205, order Oscilllatoriales, was determined from a microcystin-containing CyanoHAB in a US Pacific NW freshwater reservoir (2019). • Large, 7.3 Mbp, genome with large numbers of genes for signaling and cellular processes, metabolizing various compounds, and transposases. • Presence of genes for gas vesicles, dinitrogen fixation (in the absence of heterocysts), phycocyanin and phycoerythrin, but not for cyanotoxins or geosmin. • In the US Pacific NW, Limnoraphis typically co-occurs in CyanoHABs with other cyanobacteria, often in the presence of microcystin. A sample from a 2019 cyanobacterial bloom in a freshwater reservoir in eastern Oregon, USA, was used to produce a metagenome from which the complete, circular 7.3 Mbp genome of Limnoraphis sp. WC205 was assembled. The Limnoraphis sp. WC205 genome contains gas vesicle genes, genes for N 2 -fixation and genes for both phycocyanin- and phycoerythrin-containing phycobilisomes. Limnoraphis was present in Willow Creek Reservoir throughout the summer and fall, coexisting with various other cyanobacteria in blooms that were associated with microcystin. The absence of cyanotoxin genes from the Limnoraphis sp. WC205 genome showed this cyanobacterium to be non-toxigenic, although it is predicted to produce cyanobactins closely related to Microcystis aeruginosa microcyclamides. DNA sequence corresponding to the Microcystis mcyG gene identified Microcystis as the microcystin producer in this lake. [ABSTRACT FROM AUTHOR]