| Plants often distribute many nutrients to the roots, and attract a large number of microorganisms throughout the whole process of growth. These microbes have a great influence on healthy plants that and establish a both complex and harmony microecological relationship of selectiving each other to survive as a result of co-evolution with host plants, it is an obvious sign of the healthy plants that the changes in the structure and abundance of the colony. As a natural component of plant micro ecosystem, endophytic actinomycetes can affect plant growth through some metabolites or signal transduction. Therefore, it is of great significance to study the relationship between different physiological states of tomato, the diversity and abundance of endophytic actinomycetes and control the Botrytis cinerea by endophytic actinomycetes.In this study, samples for tomato plants infected by B.cinerea and adjacent healthy plants were collected used to islate actinomycetes. Preliminary analysis of the diversity of actinomycetes in root by morphological and molecular biological classification, and by the method of plants surface disinfection, grinding, coating plate dilution, the separation and purification of culture;antagonistic actinomycetes were selected by confrontation culture method against B.cinerea, study on the broad spectrum activity of antagonistic endophytic actinomycetes by plate growth inhibition method, 11 the pathogenic fungi is B.cinerea; We performed polyphasic taxonomy on strain NEAU-FJL2. The main conclusions are as follow:(1) The actinomycetes community was single, and the total number of the strains was large in the healthy plant; however, the community structure of diseased plant is rich but the overall number is small; there is no duplicate strain isolated from healthy and diseased plants. The results showed that the community structure and abundance of actinomycetes in the root of tomato were significantly changed after infection by B.cinerea.(2) By plate growth inhibition assay, 131 strains antagonistic against B.cinerea were screened, 20 active strains were obtained, 13 strains isolated from healthy plants whose proportion was 16.7%, 7 strains isolated from diseased plants whose proportion was 12.1%. The proportion and number of endophytic actinomycetes antagonism B.cinerea isolated from healthy tomato roots were higher than that of the diseased plant. 20 active strains were tested against 10 kinds of pathogenic fungi, and 5 strains with broad spectrum antagonistic activity were obtained Thefermentation extracts of 5 strains were tested for the antibacterial activity of the 11 kinds of fungi,and they all had different degrees of antibacterial activity.Strain NEAU-FJL2 was isolated from tomato root(Solanum lycopersicum L.) and characterised using a polyphasic approach. Morphological and chemotaxonomic properties of strain NEAU-FJL2 T were consistent with the description of the genus Dactylosporangium. Fingershaped sporangia was observed to form on short sporangiophores branching from the substrate hyphae. The cell-wall peptidoglycan was found to contain meso- and 3-hydroxy-diaminopimelic acids; arabinose, mannose, rhamnose and xylose were found as whole-cell sugars. The phospholipid profile was found to consist of diphosphatidylglycerol, phosphatidylethanolamine,phosphatidylglycerol and phosphatidylinositol. The predominant menaquinones were identified as MK-9(H8) and MK-9(H6). The major fatty acids were identified as iso-C16:0, C16:1ω7c and isoC15:0. Consequently, it is proposed that strain NEAU-FJL2 represents a novel species of the genus Dactylosporangium, for which the name Dactylosporangium solaniradicis sp. nov. is proposed. |
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