Borborobacter xinjiangensis sp. nov., a moderately halophilic bacterium isolated from grapevine rootstock in Xinjiang, China.

A Gram-negative, facultatively anaerobic, non-motile, and non-spore-forming rod-shaped bacterium, designated strain NGMCC 1.201702T, was isolated from grapevine rootstock in a vineyard in the Xinjiang Uygur Autonomous Region, China. This isolate represents the first reported member of the genus Borborobacter recovered from a plant-associated environment. Before this study, the genus was known only from arsenic-contaminated aquifer sediment. A comprehensive polyphasic taxonomic study was conducted to determine its precise taxonomic position. Strain NGMCC 1.201702T showed the highest 16S rRNA gene sequence similarity to Borborobacter arsenicus KCTC 52625T (98.29%), while digital DNA-DNA hybridization (23.50%) and average nucleotide identity (79.70%) values with this closest relative were well below species demarcation thresholds. The sole respiratory quinone was ubiquinone-10. The major cellular fatty acids (> 10%) were C18:0, cyclo-C19:0 ω8c and Summed feature 8 (C18:1 ω7c and/or C18:1 ω6c). The polar lipid profile consisted of phosphatidylethanolamine, phosphatidylcholine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylmonomethylethanolamine, an unidentified aminophospholipid, an unidentified aminolipid, two unidentified phospholipids (PL1-2), and four unidentified lipids (L1-4). The genomic DNA G + C content was 61.32%. Qualitative screening assays showed positive reactions for indolic compounds and siderophore production. Genome analysis identified genetic features potentially associated with stress adaptation and iron/tryptophan metabolism, providing additional ecological context for this plant-associated isolate. Based on phenotypic, phylogenetic, genomic, and chemotaxonomic evidence, strain NGMCC 1.201702T represents a novel species of the genus Borborobacter, for which the name Borborobacter xinjiangensis sp. nov. is proposed. The type strain is NGMCC 1.201702T (= CGMCC 1.61957T = JCM 37105T).