Phytohalomonas tamaricis gen. nov., sp. nov., an endophytic bacterium isolated from Tamarix ramosissima roots growing in Kumtag desert.

Abstract

A gram-stain-negative, aerobic, non-spore-forming, rod-shaped, non-motile bacterium strain R4HLG17T was isolated from Tamarix ramosissima roots growing in Kumtag desert. The strain grew at salinities of 0-16% (w/v) NaCl (optimum 5-6%), pH 5-9 (optimum 7) and at 16-45°C. Based on 16S rRNA gene sequence similarity, strain R4HLG17T belonged to the family Halomonadaceae and was most closely related to Halomonas lutea DSM 23508T(95.1%), followed by Halotalea alkalilenta AW-7T(94.8%), Salinicola acroporae S4-41T(94.8%), Salinicola halophilus CG4.1T(94.6%), and Larsenimonas salina M1-18T(94.4%). Multilocus sequence analysis (MLSA) based on the partial sequences of 16S rRNA, atpA, gyrB, rpoD, and secA genes indicated that the strain R4HLG17T formed an independent and monophyletic branch related to other genera of Halomonadaceae, supporting its placement as a new genus in this family. The draft genome of strain R4HLG17T was 3.6Mb with a total G + C content of 55.1%. The average nucleotide identity to Halomonas lutea DSM 23508T was 83.5%. Q-9 was detected as the major respiratory quinone and summed feature 8 (C18:1ω7c/C18:1ω6c), summed feature 3 (C16:1ω7c/C16:1ω6c), and C16:0 as predominant cellular fatty acids. On the basis of chemotaxonomic, phylogenetic, and phenotypic evidence, strain R4HLG17T is concluded to represent a novel species of a new genus within Halomonadaceae, for which the name Phytohalomonas tamaricis gen. nov., sp. nov., is proposed. The type strain is R4HLG17T (=ACCC 19929T=KCTC 52415T).