Screening And Evaluation Of Antagonistic Organisms Against Pyricularia Grisea And Xanthomonas Oryzae PV.Oryzae

1015 bacteria strains were isolated from rice soil field in Nanjing,Fengxian,Siyang of Jiangsu Province. Among the tested strains,10 strains could inhibit the growth of eight plant pathogens of Pyricularia grisea, Rhizoctonia solani, Xanthomonas oryzae pv. oryzae, Xanthomonas oryzae pv.oryzicola, Ustilaginoidea oryzae, Fusarium graminearum, Aspergillus niger and Aspergillus flarres. Two strains, T392 and T429, had strong inhibitory activity against Pyricularia grisea and Rhizoctonia solani, with the inhibition rate of 61.1%,40.8% and 62.6%,40.3%, respectively. Screening Bacillus thuringiensis against Pyricularia grisea showed that 61 strains of Bacillus thuringiensis were abtained from 570 strains. Among the tested strains,6 strains Bacillus thuringiensis had strong inhibitory activity against Pyricularia grisea, with the inhibition rate of over 60%; 6 strains had any inhibitory activity against Xanthomonas oryzae pv. oryzae; the inhibit rate of PS2D8and MO3B9 against Ustilaginoidea oryzae were 55.56% and 66.67%.Determining antagonistic bacterias of production of enzymes,siderophore and phosphate solubilizatio, the result showed that 10 antagonistic bacterium were not the producer of chitinase, T429,T533,T553,JT261 and JT301 could produce proteinase, cell ulase and siderophore,T455,T457,JT81 and JT84 could produce proteinase and siderophore,T392 could produce siderophore and phosphate solubilizatio. Certainly, it was also possible that other antibiotic materials could play a role in antibiosis. Effect of antagonistic bacterium on rice growth promotion, the result showed that 10 antagonistic bacterium on rice hight promotion rate were low,and on the rice root and dry weight promotion rate were high. The results of compatibility antagonistic bacterium with tricyclazole showed that the plate contain 3000μg/mL tricyclazole the colony was little,and in the plate contain 4000μg/mL tricyclazole the colony was grow hardly.The results of antagonistic bacterium control rice blast and rice bacterial leaf blight showed that the T392 and T429 control rice seeding blast effect was 69.4% and 61.1%, and the control rice blast effect was 54.20%,51.91%; the control seeding stage of rice bacterial leaf blight effect was 68.25%,57.14%,and the contron rice bacterial leaf blight effect was 45.56%,40.29%. The results of Bacillus thuringiensis control rice sheath blight and rice bacterial leaf blight showed that the control rice sheath blight effect of MO3B9 was 54.69%; the control rice bacterial leaf bligh effect of PS7F4,PS9F2 and PS2D8 were about 30%.The results of antagonistic bacterium and tricyclazole control rice seeding blast was that the control effect of T392,T429 and tricyclazole compatibility using 1:5 proportion was best.Based on the morphology, physiological, biochemical characteristics and 16S rDNA sequence analysis, the strains T429,T455,T457,JT81,JT84,JT261 and JT301 were identified to be Bacillus subtilis, T553 was identified to be Bacillus amyloliquefaciens, T392 was identified to be Burkholderia.