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

Bueno-Gonzalez, Victoria; Brady, Carrie; Denman, Sandra; Allainguillaume, Joël; Arnold, Dawn

Abstract

As the current episode of Acute Oak Decline (AOD) continues to affect native British oak in the United Kingdom, ongoing isola-tions from symptomatic and healthy oak have yielded a large Pseudomonas species population. These strains could be divided into taxa representing three potential novel species. Recently, two of these taxa were described as novel Pseudomonas species in the Pseudomonas fluorescens lineage. Here, we demonstrate using a polyphasic approach that the third taxon represents another novel Pseudomonas species. The 16S rRNA gene sequencing assigned the strains to the Pseudomonas aeruginosa lineage, while multilocus sequence analysis (based on partial gyrB, rpoB and rpoD sequences) placed the 13 strains in a single cluster on the border of the Pseudomonas stutzeri group. Whole genome intra-species comparisons (based on average nucleotide identity and in silico 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 Pseudomonas kirkiae sp. nov., with the type strain FRB 229T (P4CT=LMG 31089T=NCPPB 4674T). The phylogenetic analyses performed in this study highlighted the difficulties in assigning novel species to the genus Pseudomonas due to its polyphyletic nature and close relationship to the genus Azotobacter. We further propose that a thorough taxonomic re-evaluation of the genus Pseudomonas is essential and should be performed in the near future.

• Journal Article Type: Article
• Acceptance Date: Jan 30, 2020
• Online Publication Date: Feb 18, 2020
• Publication Date: Feb 18, 2020
• Deposit Date: Feb 25, 2020
• Publicly Available Date: Feb 27, 2020
• Journal: International Journal of Systematic and Evolutionary Microbiology
• Print ISSN: 1466-5026
• Electronic ISSN: 1466-5034
• Publisher: Microbiology Society
• Peer Reviewed: Peer Reviewed
• Volume: 70
• Issue: 4
• Pages: 2426-2434
• DOI: https://doi.org/10.1099/ijsem.0.004055
• Keywords: Ecology, Evolution, Behavior and Systematics; Microbiology; General Medicine; Acute Oak Decline; Azomonas; Azotobacter; Pseudomonas and Pseudomonas kirkiae
• Public URL: https://uwe-repository.worktribe.com/output/5536402