Sequencing of invertebrate viruses in water samples of Teltow Canal and Havel River, Germany

In an attempt to explore the RNA viromes of two German rivers, we searched the virus particle content of each one 50-L water sample of the Teltow Canal and the Havel River for viruses assumed to infect invertebrates. More than 300 complete and partial virus genomes up to a length of 37 kb were identified with noda-like and reo-like viruses being most abundant, followed by bunya-like and birna-like viruses. Viruses related to the Permutotetraviridae, Nidovirales, Flaviviridae, Rhabdoviridae, Chuviridae as well as the unclassified Jingmen virus and Negev virus groups were also present. The results indicate a broad extent of recombinant virus genomes supporting the concept of the modularity of eukaryotic viruses. For example, novel combinations of genes encoding replicase and structural proteins with jellyroll fold have been observed. Less than 35 viruses could be assigned to existing virus genera. These are (i) an avian deltacoronavirus which was represented by only one short contig - albeit with 98% similarity, (ii) a seadornavirus and a rotavirus, and (iii) some 30 nodaviruses. All remaining viruses are novel and too diverse for accommodation in existing genera. Many of the virus genomes exhibit ORFans encoding hypothetical proteins of up to 2000 amino acids without conserved protein domains.