Endophytic Actinomycete Resources From Sophora Alopecuroides L. And Its Evaluation Of Biocontrol Effect

Endophytic actinomycetes were widespread in the all kinds of terrestrial and aquatic plants which had currently been found. Its diversity was influenced by many factors. Different areas or site, climate conditions, and vegetation can affect the diversity of the endophytic actinomycetes groups. Research showed that medicinal plants contain a large number of beneficial endophytic actinomycetes which has close ecological relationship with the host. The secondary metabolites produced by the plant endophytic actinomycetes had gotten more and more significant application in medicine, plant disease biology controls, and become the important direction in finding new active natural products.In this paper, we chose Sophora alopecuroides L. as the object, which is the important medicinal psammophyte in the arid desert of Ningxia. Endophytic actinomycetes from S. alopecuroides L. were isolated, identified and made diversity analysis. Soon afterwards, active strains of them were screened by biological method, determined the taxonomic status by16S rRNA gene sequence similarity analysis and done their evaluation of biocontrol effect. The main conclusions were as follows:1. The health Sophora alopecuroides L. which separated158endophytic actinomyces were collected from6different samples of different soil types and different preponderant vegetations in Baijitan national nature reserve in Ningxia. In different originations of same plant, root has the most number of endophytic actinomyces, followed by seed, and the leaf has the least.And the number of endophytic actinomyces from Sophora alopecuroides L. which grow in light sierozem is more than which grow in sandy soil. The result shows that the Streptomyces and Nocardia were the main genera of endophytic actinomyces. The Albosporus was mainly group in Streptomyces.2. Through transparent circle method, the feature of excreting enzyme about126endophytic actinomycetes from Sophora alopecuroides L. in arid desert region of Ningxia, was studied. The results showed that the71strains can produce enzyme, accounting for56.3%of total isolates, in which8strains were the most significantly active. In these strains, NDZKDS73and NDZKDS7strains were the highest on amylase activity, the transparent circle radius were24.62and19.12mm, respectively; FJYKDS5strain was the highest on protease activity, the transparent circle radius was16.94mm; FJYKDS11and BJGKDS2strains were the highest on cellulase activity, transparent circle radius were24.72and22.40mm, respectively; FJJKDS2strains was the highest on chitinase activity, transparent circle radius was17.76mm; NDZKDS24and NDZKDS20strains were highest on glucanase activity, transparent circle radius were12.06and10.50mm, respectively. By morphological characteristics and16S rRNA gene sequence similarity analysis,7strains were identified as Streptomyces and1strain were Nocardiopsis in8strains.3. Through antimicrobial activity tests in vitro,126endophytic actinomycetes strains from the Sophora alopecuroides L. were done antimicrobial activity test with6kinds of target pathogens. The results showed that the15strains have better inhibiting effects on target pathogens than others, accounting for56.3%of total isolates. In these strains, YWZKDS4strains inhibition zone against Pyricularia oryzae reachs up to15.12mm; NDZKDS65strains inhibition zone against Fusarium oxysporum reachs up to18.54mm; NDZKDS22strain has broad-spectrum antibacterial activity, its inhibition zone against5kinds of target pathogens was more than10mm. By morphological characteristics and16S rRNA gene sequence similarity analysis, YWZKDS4, NDZKDS22and NDZKDS65respectively with Streptomyces scabiei, Streptomyces albospinus, Streptomyces capillispiralis have closest relative, sequence similarity was99.1%,96.4%and99.1%.4.28strains was selected representative strains of endophytic actinomycetes from sophora alopecuroides, By chromogenic method and plate culture method for its ability to IAA secrete, inhibit the activity of weed seed germination. The results show that1strains NDZKDS1with pink color reaction;3strains YCZKDS3, FJJKDS19, NDZKDS22fermented liquid of weed seed germination have obvious inhibition effect. By morphological characteristics and16S rRNA gene sequence similarity analysis,1strain had higher ability in IAA secret were Nocardiopsis,3strains of fermented liquid can inhibit weeds active strains were identified as Streptomyces in4strains.