Isolation And Composition Analysis Of Secondary Metabolites From A Strain Of Bacillus Amyloliquefaciens Which Inhibit Rice Blast Fungus

Rice blast is one of the most serious diseases affecting rice yield. Currently,We screen resistant rice varieties and chemical control of methods to prevent and treat. With the improvement of people’s living standards,the improvement of blast resistance, the reduction of resistant varieties associated resistance.The demand of prevention increase which use natural biological pesticides and other biological means.This study is starting from a Bacillus that can inhibit the rice blast growth which from traditional Chinese medicine antibacterial test. Through the bacterial secondary metabolites were isolated and purified, find a clue that several biologically active metabolites,and determination of the molecular weight of one of the active substance.Test select the best strain which from five pairs of strains have rice blast inhibitory effect which find in traditional Chinese medicines,and tentatively named it Rdx5. After morphological observation, starch hydrolase observation and 16SrDNA Phylogenetic analysis,we confirmed the strain Rdx5 is Bacillus amyloliquefaciens.The total synthesis Landy medium were selected and ferment for Rdx5. Filter bacteria and bacterial fermentation have good inhibitory effect. Antibiotic susceptibility tests, Rdx5 exhibit sensitive to many antibiotics.Rdx5 of secondary metabolites, with a variety of rice blast inhibit bioactive substances. After the liquid extraction, the chloroform layer methanol layer, the aqueous layer were active. Chloroform/acetone assignment and HPLC analysis discovery that only in chloroform extract layer contains at least three biologically active substance. Secondary metabolites which inhibit Rice Blast has good thermal stability and UV stability,but have poor pH stability. By liquid extraction, high performance liquid chromatography, a test selection were isolated and purified in several secondary metabolites with antibacterial activity. And finally got the biologically active substances, Mass spectral analysis showed the molecular weight active substance is 586.2759.