为了解药用植物内生放线菌次级代谢产物合成潜能,采用2种不同的发酵培养基对39株分离自5种药用植物根部的内生放线菌进行发酵,利用甲醇抽提发酵液,然后对抽提液进行13株病原指示菌的抗菌活性测定.结果显示32株(82%)供试菌的发酵抽提液至少对1种病原指示菌表现出抑制活性.为进一步评价供试菌株的次级代谢产物合成潜能,对所有供试菌株的基因组DNA进行了聚酮合酶(PKS)基因与非核糖体肽合成酶(NRPS)基因的扩增及检测.结果表明:所有供试菌株至少能扩增出1种次级代谢产物合成基因,其比例为PKS I型(1)(59%)),PKS I型(2)(62%),PKS II型(82%),NRPS(1)(100%),NRPS(2)(100%),表明大多数药用植物内生放线菌具有合成聚酮类和非核糖体肽类化合物的潜能,在适宜的培养条件下可能产生这些种类的活性物质,有待进一步开发.
In order to understand the biosynthetic potential of medicinal endophytic actinomycetes,39 strains isolated from roots of 5 species of medicinal plants were fermented in two different media.Then methanol was used to extract the fermentations.After getting the crude extracts,the bioactivity test of crude extracts were performed on 13 strains of indicator bacteria and fungi.About 32(82%)of the crude extracts exhibited bioactivity to one of the 13 indicator bacteria and fungi at least.To further verify the biosynthetic potential of the 39 strains,the polyketide synthases(PKS)and nonribosomal peptide synthetases(NRPS)genes were amplified.One of the several genes at least could be amplified from genomic DNAs of all of the strains,and the proportions for the type I PKS(1),type I PKS(2),type II PKS,NRPS(1) and NRPS(2) are 59%,62%,82%,100% and 100%,respectively.These results above suggested- that the endophytic actinomycetes from medical plants possessed significant biosynthetic potential,and they could produce active compounds under certain conditions.
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