Methylobacillus draconifructis sp. nov., a New Species of Methylotrophic Bacteria from Pitahaya

Abstract Two novel isolates of obligate methylotrophic bacteria, strains Pita1T and Pita2, were obtained from tissues of pitahaya fruits (Hylocereus sp., Vietnam) purchased from a supermarket at different times (January and March 2022). The isolates were aerobic, gram-negative, motile rods and grew optimally at 29–37°C and pH 7.0–8.0, in the presence of 0–2.0% NaCl in the medium. Both strains utilized methanol (up to 4% in the medium) as a carbon and energy source, and strain Pita1T also grew on methylamine. The predominant fatty acids in the cell composition were C16:0, C16:1ω7c, and C17cyc, and the major ubiquinone was Q8. The dominant phospholipids were phosphatidylethanolamine, phosphatidylcholine, phosphatidylglycerol, and diphosphatidylglycerol. The 16S rRNA gene sequences of strains Pita1T and Pita2 had 99.6% similarity with each other and 97.7–99.5% with the type members of the genus Methylobacillus. The genome size of strain Pita1T was 3.0 Mb with DNA G + C content of 57.5%, while that of strain Pita2 was 3.1 Mb with DNA G + C content of 57.0%. The values of the ANI and dDDH with the type strains of the genus Methylobacillus were 74.36–92.76% and 18.8–51.0%, respectively, which is below the proposed threshold for delineation of prokaryotic species. Based on the results of phylogenetic, phenotypic and chemotaxonomic analyses, the new strains Pita1T (= VKM B-3933T = BIM B-2126T) and Pita2 (= VKM B-3966 = BIM B-2127) were assigned to a new species of the genus Methylobacillus, for which the name Methylobacillus draconifructus sp. nov. is proposed.