Isolation Screening And Identification Of Antagonistic Bacteria Against Ustilago Scitaminea Sydow And Studies On Their Antagonistic Mechanisms

Nine hundred and twenty-eight bacteria strains were isolated from 54 samples (sugar cane leave, bud, stalk, root and soi I s of the different growth stages of sugarcane ), of which, the number of strains with antagonism to Usti lago scitaminea Sydow was 301 strains. By rescreening experiements 18 strains (A3^ A4B> A6i> A66x B6N Bn> Bu> B,7, B24, B26l B30> B3^ B37> B39N B42> B43N B9i,Bioo ) were selected as potential biocontrol agents for sugarcane smut caused by U. scitaminea, and then used in the study of identification and antagonistic mechanism by PCR.Through Bio log GN identification results were that strain Bioois i dent i f i ed as Pseudomonas aeruginosa\ B24 i s i dent i f i ed as Acinetobacter genospecies 10; B30 as Burkholderia cocovenenans and QM is identified as Serratia marcescens \ Twelve strains(A3^ A46> A6i> A6e> Bu> B26, B3]^ B37N B39> B4?x B43x B9D are Bacillus', two strains (B6N B,,) are Pseudomonas. Based on the sequence related to mycosubti I in synthetase of Bacillus subtilus , primers are designed to amplify the genomic DNA among the A34^ A46^ A6is A66>B14^B^ B24N 630^6,00 and B3 strai ns of antagoni st ic bacteria. A band of about 2.2kb length was gained in 6 strains (A34, A46, A6i, A66, B)4 and B3), of which, the bands of A34 and B3 are sequenced. Studies of antagonistic mechanism show that Bacillus subtilus ismainly dependent on antibiotics production. Sequence analysis showed that the gene related to the biosynthesis mycosuti Iin, a potent antifungal peptide antibiotics, which belong to the Iturin fami ly of lipopeptide antibiotics.lt can conclude that the antagonistic mechani sm of the strai n (A34, A4e, A6i, A66, B,4 , B3 ) i s associated with producing lipopeptide antibiotics. The strains are most likely to be well biocontrol prospect and commercially used in fields for disease controlling and worth doing further research.