Study On The Herbicidal Substance From Secondary Metabolite Of Aureobacidium Pullulans PA-2

In the early a pathogenic fungi PA-2 strain was isolated and purificated from poplar leaves at ping an county in the eastern city of qinghai province by bio-control lab of Institute of Plant Protection of Agriculture and Forestry Science of Qinghai University. It is sure that PA-2 has nice control effects for broadleaf weeds,such as quinoa,sorrel leaf smartweed,cleavers, malva, large cephalanoplos and gramineous weeds wild oats in the field by idefiniting its biological activity determination,and has potential in research and development of secondary metabolites microbial herbicides from pathogenic fungi. After morphological identification and ribosomes ITS sequence alignment, PA-2 for has been Identificated as Aureobacidium pullulans. According to many previous research reports, metabolites of the kind of fungus are mostly used in medicine manufacture, fusi product packaging, retain freshness, the tobacco industry, agricultural seeds and other fields. But in the field of pesticide, there is nothing about secondary metabolites of budding short stalks enzyme was used to synthesis the herbicides to control weeds.The experiment developed to isolate and purificate the crude extractings from budding short stalks enzyme, through active tracking method, expecting to get material with herbicidal activity, identify its chemical structure, and a preliminary study the mechanism of inhibiting the growth and metabolic of wild oats, laying a certain foundation for the prevention and control of weeds by microbial secondary metabolites.1. The number of fermented liquids of Aureobacidium pullulans PA-2 strains was extracted by equal volume of n-butyl alcohol, ethyl acetate, chloroform three times, respectively combine the same organic phase, obtain crude extract extract via reducing pressure concentration and rotary evaporation. The best active organic phase- ethyl acetate phase was cleared with activity Identification that is treating the germination of wild oat seed with each crude organic phase extractings.2. Using column chromatography to isolate ethyl acetate crude extractings from PA-2, 16 fractions were obtained, among them 9, 4, 7, 11 with herbicidal activity. While continuing to carry out SephadexLH-20 gel column chromatography for them the composition 9, 11 were geted,and control effect for wild oat has been proved very well at the concentrations in 800 ug/mL.3. Rour component 7-1 、 11-1 、 9-1 、 9-2 was obtained by thin-layer chromatography purification preparation for distillate 7, component 9,11.The maximum absorption peak of the four component respectively are 300.5 nm and 287.5 nm, respectively 287.5 nm and 289.5 nm. Among them component 9-1 is the best one in herbicidal activity by biological activity assay.4. With the best active components to explore its Inhibiting mechanism for wild oats. The result shows that the component 9 interfere and suppress the photosynthesis process of wild oats.