sp. nov., a novel species isolated from oak in the United Kingdom, and phylogenetic considerations of the genera , and .

As the current episode of Acute Oak Decline (AOD) continues to affect native British oak in the United Kingdom, ongoing isolations from symptomatic and healthy oak have yielded a large species population. These strains could be divided into taxa representing three potential novel species. Recently, two of these taxa were described as novel species in the lineage. Here, we demonstrate using a polyphasic approach that the third taxon represents another novel species. The 16S rRNA gene sequencing assigned the strains to the lineage, while multilocus sequence analysis (based on partial , and sequences) placed the 13 strains in a single cluster on the border of the group. Whole genome intra-species comparisons (based on average nucleotide identity and DNA-DNA hybridization) confirmed that the strains belong to a single taxon, while the inter-species comparisons with closest phylogenetic relatives yielded similarity values below the accepted species threshold. Therefore, we propose these strains as a novel species, namely sp. nov., with the type strain FRB 229 (P4C=LMG 31089=NCPPB 4674). The phylogenetic analyses performed in this study highlighted the difficulties in assigning novel species to the genus due to its polyphyletic nature and close relationship to the genus . We further propose that a thorough taxonomic re-evaluation of the genus is essential and should be performed in the near future.