Taxonomic description of Pseudomonas rhizovicinus sp. nov., isolated from the rhizosphere of a desert shrub Haloxylon ammodendron.

A Gram-negative aerobic bacterium, strain M30-35 T, was isolated from the rhizosphere of Haloxylon ammodendron in Tengger desert, Gansu province, northwest China. Our previous research indicated that strain M30-35 T can promote the growth of ryegrass (Lolium perenne L.). In this study, strain M30-35 T was subjected to a polyphasic taxonomic study. Phylogenetic analysis of the 16S rRNA gene and two other housekeeping genes (gyrB, rpoD) showed that strain M30-35 T is a member of Pseudomonas anguilliseptica group. The average nucleotide identity (ANI) scores for strains KMM 3042 T and FR1439T were 76.5% and 83.7%, respectively, and DNA-DNA hybridization (DDH) were 21.6% and 26.6%, respectively, and the rates were less than the threshold range for species determination. The dominant cellular fatty acids of strain M30-35 T were C16:0 (22.7%), summed feature 3 (C16:1ω7c and/or C16:1ω6c; 18.5%), summed feature 8 (C18:1ω7c and/or C18:1ω6c; 23.1%). The major polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phospholipid and aminophospholipid and the predominant respiratory quinone was ubiquinone (Q9). On the basis of above data, it can be concluded that strain M30-35 T represents a novel species in the genus Pseudomonas, for which the name Pseudomonas rhizovicinus sp. nov. is proposed. The type strain is M30-35 T (= MCCC 1K03247T = KCTC 52664 T).