Isolation, Screening Of Actinomycetes From Mangrove Sediments With Nematicidal Activity And Identification Of Three Active Strains

Meloidogyne spp. is a kind of foliage autoeciousness nematodes which disserves greatly, distributes widely, be difficult for prevention and cure and endangers the production of crop heavily. Meanwhile, it is one of the important causes that place a premium on vegetation disease. At present, the nematodes biological control has been paid much attention at home and abroad There are rich actinomycetes resources in mangrove sediment, which are important origin of secondary metabolizing productions. This article aimed to sampling and isolate actinomycetes from mangrove sediment in Dongzhaigang of Hainan Island. And then isolate actinomycetes and determine nematocidal activity opposite to fermentation of actinomycetes, sort and identify active fungus strain. Results list as follows:11samples of mangrove sediment were gathered and then206actinomycetes were isolated by dilution-plate method, which included7categories. The quantities of Streptomyce were the most, accounted for63%. Singularity rare actinomycetes accounted for37%, thereinto, Micromonospora accounted for18%, Saccharopolyspora accounted for8%, Pseudonocardia, Tsukamurella,Norcardiopsis accounted for3%respectively, Isoptericola accounted for2%.Determine the anti-nematode activities of fermentation liquor of206actinomycetes. After the first of filter,28strains which had better activity were obtained. Through double filter, HA11055,HA11090,HA11166strains were finally confirmed to have high acticity and stable heredity, their mortality rates were54.2%,65.0%and56.6%respectively.To test modality and culture characters, biophysical and biochemistry characters,16S rDNA sequence and construct phylogenetic tree of3actinomycetes which were anti-nematocidal activity. Strain HA11090was identified as Saccharopolyspora jiangxiensis. Strain HA11055wes identified as Streptomyces sp.HA11055. Strain HA11166was identified as Nocardiopsis sp. HA11166. Strain HA11055and HA11166maybe new strain, which were worth researching further on DNA-DNA hybridization.