Characterization And Polyphasic Taxonomy Of New Bacterial Strains From Alpine Frozen Soils And Subnival Plants

Bacteria from alpine frozen soils live in the environment with low temperature, oligotrophic system, and the absence of liquid water and O2. So Bacteria from alpine frozen soils are kinds of extreme microorganism. Bacteria from alpine frozen soils have lots of species. At the same time, their metabolites are new types resources and have great benefit to people. To develop new types resources, people must isolate more bacteria from alpine frozen soils, and classify and identify them.Endophytic bacteria residing within plant tissues without any harm to the plant play active roles in plant. It could be a new approach to explore ecosystem type agriculture. To develop new types resources, people must isolate more bacteria from plants living all kinds of environments, and classify and identify them.My paper mainly classify and identify strains isolating from alpine frozen soils and subnival plant-Leontopodium leontopodoides, and confirm their new taxonomic positions.1. Strain TSBY 57T and strain TSBY 67T were isolated from alpine permafrost. Strain Enf 54T was isolated from Leontopodium leontopodoides in Tianshan Mountains. Their pure cultures which we obtain provide good material of study. We have firstly performed systematic taxonomy of isolated strains from alpine permafrost and Leontopodium leontopodoides, in Tianshan Mountains.2. Cells of strain TSBY 57T are non-spore-forming, non-motile rods,0.2-0.3μm in diameter and 0.3-1.1μm in length. Colonies are yellow; Cells of strain TSBY 67T are non-spore-forming, non-motile rods,0.3-0.5μm in diameter and 0.6-1.6μm in length. Colonies are smooth and shiny, orange-yellow. Flexirubin type pigments are produced; Cells of strain Enf 54T are non-endospore-forming, non-motile, irregular-shaped rods,0.3μmin diameter and 0.9μm in length. Colonies are pale yellow. Therefore, their morphological features are respectively in accordance with morphological features of their respective genus. These results lay the foundation for classification and identification in the aspect of morphology.3. Strain TSBY 57T grew with 0-1.5% NaCl, at 0-30℃, and at pH 6-8; Strain TSBY 67T grew with 0-2% NaCl, at 4-37℃, and at pH 6-8; Strain Enf 54T grew with 0-4% NaCl, at 4-30℃, and at pH 6.0-8.5. As a conclusion, they have cold resistance to a certain extent. That is external expression that they adapt to low temperature all the year round.4. In light of the physiological and chemical tests, Strains TSBY 57T, TSBY 67T and Enf 54T are respectively considered to have generality of their respective genus and have obviously distinct from other closely related members of their respective genus.5. We conclude that the fatty acids'composition of TSBY 57T, TSBY 67T and Enf 54T were respectively consistent with those of the closest phylogenetic neighbours grown under the same conditions. However, the content of fatty acids differed from them by higher proportions by lower proportion. Hence, it is a powerful evidence to classify and identify.6. Studying by means of molecular biology, The DNA G+C content of strain TSBY57T, TSBY67T and Enf 54T were respectively 34.1mol%,33.5 mol% and 66.8mol%, lying within the range reported for members of their respective genus. On the basis of the sequence similarity of 16S rRNA gene, strain TSBY 57T was closely related to members of the genus Epilithonimonas, strain TSBY 67T was closely related to members of the genus Chryseobacterium and strain Enf 54T was closely related to members of the genus Frondihabitans.Therefore, based on polyphasic taxonomic analytical results, strain TSBY57T represents a novel species of the genus Epilithonimonas, which is named as Epilithonimonas xinjiangense sp. nov., strain TSBY 67T represents a novel species of the genus Chryseobacterium, which is named as Chryseobacterium xinjiangense sp. nov., and strain Enf 54T could be a novel species of the genus Frondihabitans, which is named as Frondihabitans xinjiangense sp. nov..