| In recent years, researchers are gradually paying attention to insect-symbiotic actinomycetes. Conventional screening resources have been exhausted in the screening process of actinomycetes (eg. Soil, Plants, Marine resources). Consequently, the screening of non-repeating strains has become an urgent problem in the finding process of natural activity product. Insects are similar to traditional resources, massive species and numbers insure that the source is adequate. Some insects also have the medicinal values, and a large number of bio-activity compounds also can be isolated in their bodies. At the same time, it could provide some potential and referable targets for actinomycetes activity tests, and have significances for finding the novel natural activity compounds.For the first time, we choose the Polyrhachis vicina Roger which the officinal insect as a new screening source in this study. The symbiotic actinomycetes were isolated, the metabolite activity of strains and the taxonomic identification of novel species. So far, we have obtained37symbiotic actinomycetes with new method from the new screening source-Polyrhachis vicina Roger. In activity tests,8kinds of extraction from fermentation broth have Anti-bacterial activity for two kinds of bacteria in more than15mm,8single colonies have better activity against plant pathogenic fungi and6kinds of extraction from fermentation broth have anti-fungal activity more than10mm for part of plant pathogenic fungus, meanwhile,2new species were identified using a polyphasic approach.3strains (NEAU-ycml, NEAU-ycm2and NEAU-ycm3)16S rDNA sequences were obtained and analyzed through the cultural morphology and active test. Two (NEAU-ycm2and NEAU-ycm3) of them belong to the genus Micromonospora, one (NEAU-ycml) belong to the genus Streptomyces. NEAU-ycml and NEAU-ycm2were characterized with a polyphasic approach, because of the lower16S rDNA gene sequences similarities of NEAU-ycml and NEAU-ycm2with the type strains of other members of the genus Streptomyces and Micromonospora, moreover, the gyr B gene sequence of NEAU-ycm2also have a low similarity. Therefore, strain NEAU-ycm1T (=CGMCC4.7094T=DSM42102T) and NEAU-ycm2T (=CGMCC4.7100T=DSM45886T) represent a novel species of the genus of Streptomyces and Micromonospora, respectively, for which the name Streptomyces polyrhachis and Micromonospora polyrhachis sp. nov. are proposed. So the new screening source and method have raised the proportion of new actinomycete, and also established a good foundation for obtaining of novel natural activity compounds. |
