RESUMEN
OBJECTIVE: The aim of this study was to identify the microbiological characteristics of a Lysinibacillus strain isolated from storage liquid in the stems of Populus euphratica trees. METHODS: Bacterial morphology and cultivation characteristics were studied by conventional cultivation and dyeing method. Biochemical characteristics, fatty acid components, menaquinone, polar lipids, phylogenetic analyses of 16S rRNA, determination of (G + C) mol% content and DNA- DNA hybridization were studied by polyphasic taxonomic approach. RESULTS: Strain ML-64 is Gram-positive, endospore-forming and rod-shaped. Colonies are pale-yellow, circular and entire margin. Temperature range for growth is between 10 and 45 degrees C (optimum at 37 degrees C ). The pH range for growth is between 6. 0 and 9.0 (optimum at 7.0). NaCl concentration range for growth is between 0 and 6% (optimum 3% ). Cells were positive for lipid esterase, Arginine dihydrolase, urease and Voges-Proskauer test. No sugars were fermented in the API 50CH strips. L-Serine, Methyl Pyruvate, α-Keto-Butyric, Acetoacetic Acid were oxidized. Resistant to polymyxin b (30 µg), novobiocin (30 µg), peillin G (10 U). 16S rRNA gene sequence demonstrated that strain ML-64 was closely related to Lysinibacillus chungkukjangi 2RL3-2T (100%) , Lysinibacillus sinduriensis BLB-1T (99.1%). DNA-DNA relatedness were 82% and 50. 9% with Lysinibacillus chungkukjangi 2RL3-2T and Lysinibacillus massiliensis CIP108446T, respectively. The genomic DNA G + C content of strain ML-64 was 36. 8% (mol). Major fatty acids were iso-C,,, (55. 05% ) and anteiso-C15,0 (20. 70% ). The predominant menaquinone is MK-7. Based on the phenotypic phylogenetic and genotypic analyses, the strain ML-64 is concluded to represent a new mutant strain of the Lysinibacillus chungkukjangi species, GenBank accession number is KC609752. CONCLUSION: As an endophytic bacterium of Populus euphratica, genomic structure of the strain ML-64 was greatly differentiated from the closest strain L. chungkukjangi, and suitably adapted to the endophytic environment of Populus euphratica.