Screening, Identification And Studies On The Fermentation Conditions Of Antagonistic Bacteria Of Tobacco Wildfire

Tobacco wildfire disease caused by pseudomonas syringae pv. tabaci is an important bacterial disease. The disease has happened more and more seriously since 1980s in tobacco fields Yunnan,Guizhou,Henan,Shandong,Hubei,Liaoning and Jilin and has already caused great economic losses each year. With the further knowledge to chemical pesticides, however, many concerns, such as the pollution of environment and 3R including Resistance,Residue,Resurgence have caused the many serious problems. Biological control by natural antagonistic organisms is a potential safe tool for crop protection against pathogenic fungi and bacteria and offers a promising alternative to synthetic pesticides, in part because it is perceived as safe to the environment and human health and can avoid the appearance of drug-resistance. The following are the conclusion of this research:(1)A total number of 127 bacterial strains were isolated from rhizosphere soils of tobacco, by tube dilution assay from tobacco fields in Jingyang Shaanxi. The result of plate test showed that six strains had antagonistic activity against the tobacco wildfire disease. According to the result of the suppression assay, strain w-5233 was selected as the one of the best effect. It's control effect of pseudomonas syringae pv. tabaci is 85.98% and was preliminarily identified as Bacillus subtilis.(2)In the test of antagonistic spectrum of bacteria against the crops pathogens,the result showed strain,w-5233 could inhibit the growth of eleven plant pathogenic fungi, besides, it shows the greatest inhibiting effect on pseudomonas syringae pv. tabaci .W-5233 shows the great inhibiting effect on Altermaria solani(E.et M.Jones et Grout), Pyricularia Oryzae Cav. , Fusarium oxysporum f.lycopersici(Sacc).snyder et Hanse, Fusariumoxyspor (Scho).f.sp.cucumbrum Owen, Alternaria alternate and Bipolaris sorokiniana. (3)In pot experiment, strain w-5233 had a protective efficiency of 85.98% and therapeutic efficiency of 76.95% against the tobacco wildfire disease. The test of control effect of antagonistic bacteria to tobacco wildfire disease by DMRT showed protection effect and curing effect reached great significant level. Strain w-5233 showed promoting effect on the tobacco growth by test of on growth-promoting effects. This strain could...