Two Gram-negative, aerobic, motile bacteria strains were isolated from leaf spot disease of Quercus mongolica. Strain hsmgli-8T has 99.86 % 16S rRNA gene sequence similarity to LY10J, and the highest 16S rRNA gene sequence similarity to Pseudomonas cerasi 58T (97.2 %), then Pseudomonas ficuserectae JCM 2400T (97.18 %), Pseudomonas meliae CFBP 3225T, Pseudomonas tremae CFBP 6111T and Pseudomonas congelans DSM 14939T (all 97.12 %), and less than 97.1 % similarity to other recognized species. In phylogenetic trees based on 16S rRNA gene and multilocus sequence data, the two novel strains form a separate branch, indicating that they do not belong to any Pseudomonas group and subgroup, and should belong to a novel species within the genus Pseudomonas. This assertion is also supported by the results of genome average nucleotide identity analysis. The major fatty acids are C16 : 0, C18 : 1 ω7c and/or C18 : 1 ω6c, C16 : 1 ω7c and/or C16 : 1 ω6c. Polar lipids include phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol, aminolipid and seven uncharacterized phospholipids. The predominant respiratory quinone is Q-9. The DNA G+C content is 59.45-59.50 mol%. Based on these data, we propose that the two novel strains should be assigned as a novel species within the genus Pseudomonas. We propose that the novel strains be named Pseudomonas quercus sp. nov. The type strain is hsmgli-8T (=CFCC 15739T=LMG 31544T).
Keywords: Pseudomonas; Quercus mongolica; average nucleotide identity; multilocus sequence analysis.