Isolation Of An Bacillus Pumilus With The Activity Of Inhibiting Rice Blast And Analysis Of Its Antimicrobial Compounds

Rice blast, rice sheath blight and rice leaf blight are the most destructive pathogens in the world for the rice. The losses caused by rice blast destroy the development of output of the rice. The means against rice blast involve chemical control, biocontrol and cultivation management. Chemical pesticides, which are cheap, operate quickly. Overuse of chemical pesticides leads to:polluting environment, being harmful to human and animals and strengthen resistibility. Biocontrol, friendly to human, animals and environment, is long-lasting and having bright future.Now, many microorganisms were used as biocontrol. Some were used to control Rice blast, such as actinomyces spp.,bacillus spp., pseudomonad spp.In our research, a strain, with strong antibacterial activity, was isolated from osmanthus fruits and named as osm-1.Accoring to the morphology identification, physiological and biochemical identification and16SrDNA identification, the strain osm-1was charaeterized as bacillus pumilus.The strain has strong antibacterial activity to rice blast, rice sheath blight, rice leaf blight. The culture broth was treated with ethyl acetate, butanol, chloroform.It can be seen that this active compound was a polar compound. It can be solubilized in water and can not in organic solvent.Besides, the compound is stable with strong heat resistance, acid and alkali resistance between the temperature of20-80℃and the PH level of2-10.The strain not only has strong antibacterial activity, but also has the ability of root colony and promoting the growth of plant.Crude products with little glucose was collected from the Purification of MCI material. After further purification of high performance liquid chromatography, the pure products were gotten and submitted to LC-MS. The molecular weight were379.2and324.1. Through contrasting in database, there was no analog in database. As a result, it maybe some new compounds.Bacillus spp. with endogenesis gemma can sustain bad environment and it is easy for transportation and store. Generally, the antibacterial compounds are antibiotics and polypeptide compounds. The polypeptide compounds have the ability to form ion channel in the cytoplasmic membrane of the pathogenicbacteria leading to the divulgence of cytoplasmic substance. If osm-1is exploited as biocontrol pesticide, it will possess good prospect to manufacture in industrialization.Besides, the strain has the ability to promote the growth of the root. So it could be exploited as a plant growth regulator.