Sreening And Identification Of Symbiotic Actinomycetes From Corydalis Yanhusuo L And Study Of Antibacterial Activity

Endophytic actinomycetes live inside the host causing no obvious harm to the host. The symbiosis for a lang time force endophytic actinomycetes to form distinctive physiological and metabolic characteristics, which make them becoming valuable microbiological resource. As a series of discovery and research on novel compounds with intense biological activities extracted and purificated from endophytic actinomycetes such as enzymes and antibiotic, the importance of endophytic actinobacteria have drawn increasing attention among agronomists, chemists and biologist day by day.In this study,a kind of medicinal Plants Corydalis yanhusuo collected from Fenghuang Mountain in Wuchang, Heilongjiang Province was used to isolated a total of 78 endophytic actinomycetes strains on ten kinds of agar media including HV, Gauze’s medium no. 1 and modified Gause Ⅱmedium with cycloheximide(50 mg l-1) and nalidixic acid(20 mg l-1) as inhibitor combination. The cross method were used to determine the antibacterial activity of all the78 actinomycetes strains and 14 strains inhibited 5 kinds of fungi. Strains YHS9, NEAU-YHS12,NEAU-YHS15, YHS37 and YHS39 were sequenced and compared on Ez Taxon-e according to morphological comparison. The results showed that YHS9 belonged to the genus Streptosporangineae, YHS37 and YHS39 belonged to the genus Micromonosporineae and NEAU-YHS12 and NEAU-YHS15 which were subjected to polyphasic taxonomy study was a member of the genus Sphaerisporangium.Phylogenetic analysis of 16 S r RNA gene sequences showed that the two strains closely related to one another(99.8 % similarity) fell within the genus Sphaerisporangium, and had the closest relationship with Sphaerisporangium cinnabarinum JCM 3291T(98.7%, 98.6%),Sphaerisporangium flaviroseum YIM 48771T(98.6%, 98.6%), Sphaerisporangium melleum JCM13064T(98.5%, 98.4%) and Sphaerisporangium dianthi NEAU-CY18T(98.4%, 98.4%). Both neighbour-joining and maximum-likelihood phylogenetic tree based on 16 S r RNA gene sequences showed that strains NEAU-YHS12 and NEAU-YHS15 formed a distinct phyletic line with the second related strain Sphaerisporangium flaviroseum YIM 48771 T which was not supported by the ow boots value. he phylogenetic distinctiveness, genomic distinctiveness and the differential phenotypic properties are suf?cient to separate strains NEAU-YHS12 and NEAU-YHS15 T from recognized species of the genus Sphaerisporangium. The high similarities of 16 S r RNA genesequences and phenotypic properties and the over 80 % DNA–DNA relatedness value between the two isolates indicate that they should belong to one species, for which the name Sphaerisporangium corydalis is proposed. The type strain is NEAU-YHS15T(CGMCC 4.7148T=DSM46732T).