Pseudomonas cistanchae sp. nov., a novel plant-associated bacterium isolated from diseased Cistanche soil in Xinjiang, China

A novel bacterial strain, designated JK66 T , was isolated from the rhizosphere soil of diseased Cistanche plants collected in Turpan, Xinjiang, China. Strain JK66 T grew at 20–42 °C (optimum, 37 °C), pH 5.0–10.0 (optimum, pH 7.0), and with 0–3.0% (w/v) NaCl (optimum, 2.0% (w/v)). The strain was selected for taxonomic characterization because of its antagonistic activity against Fusarium acuminatum and its potential to produce indole-3-acetic acid. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain JK66 T belongs to the genus Pseudomonas , showing the highest sequence similarity to Pseudomonas borbori R-20821 T (98.70%), followed by Pseudomonas cuatrocienegasensis 1N T (98.46%), Pseudomonas segetis CIP108523 T (98.35%), Pseudomonas marincola KMM3042 T (98.32%) and Pseudomonas xionganensis R-22-3w-18 T (98.15%). The DNA G+C content of strain JK66 T was 61.63%. The average nucleotide identity and digital DNA–DNA hybridization values between strain JK66 T and closely related type strains were 76.82–82.06% and 21.10–25.30%, respectively, which are below the threshold values for species delineation. Chemotaxonomic analyses showed that the respiratory quinone was ubiquinone Q-9. The major polar lipids comprised diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, unidentified phospholipid, unidentified glycolipid, unidentified phosphoglycolipid and two unidentified lipids and the predominant fatty acids (>5%) were C 12:0 , C 12:0 3-OH, summed feature 3, C 16:0 and summed feature 8. On the basis of phenotypic, physiological, biochemical, phylogenetic and genomic evidence, strain JK66 T represents a novel species within the genus Pseudomonas , for which the name Pseudomonas cistanchae sp. nov. is proposed. The type strain is JK66 T (=CCTCC AB 2025123 T =LMG 34229 T ). The GenBank accession numbers for the 16S rRNA gene sequence and the whole-genome sequence are PX795502 and JBTLWN000000000, respectively.