Siya Wu, Delong Kong, Hao Xu, Xinran Wang, Wei Zhang
A novel bacterial strain, designated JK66T, was isolated from the rhizosphere soil of diseased Cistanche plants collected in Turpan, Xinjiang, China. Strain JK66T 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 JK66T belongs to the genus Pseudomonas, showing the highest sequence similarity to Pseudomonas borbori R-20821T (98.70%), followed by Pseudomonas cuatrocienegasensis 1NT (98.46%), Pseudomonas segetis CIP108523T (98.35%), Pseudomonas marincola KMM3042T (98.32%) and Pseudomonas xionganensis R-22-3w-18T (98.15%). The DNA G+C content of strain JK66T was 61.63%. The average nucleotide identity and digital DNA-DNA hybridization values between strain JK66T 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 C12:0, C12:0 3-OH, summed feature 3, C16:0 and summed feature 8. On the basis of phenotypic, physiological, biochemical, phylogenetic and genomic evidence, strain JK66T represents a novel species within the genus Pseudomonas, for which the name Pseudomonas cistanchae sp. nov. is proposed. The type strain is JK66T (=CCTCC AB 2025123T=LMG 34229T). The GenBank accession numbers for the 16S rRNA gene sequence and the whole-genome sequence are PX795502 and JBTLWN000000000, respectively.