Characterization Of Antimicrobial Substances Produced By Pseudomonas Aurantiaca JD37and Its Role In Growth Promotion And Disease Suppression In Oilseed Rape

Crop diseases are caused by infestation from roots or stems by bacterium, fungal, viruses and nematodes appropriate situation. For the accumulation of extent of endanger with the increase of years of continuous cropping, it cuts production,even destruct totally of crops which leads to severe economical loss. Previous studies showed that approximate80%crop diseases are caused by fungal. Current chemical pesticides application leads quite a lot hazards such as hazardous substance residue, environment pollution and food pollution. It also generates resistant which weakens disease resistance efficiency.Our research group obtained a strain of Pseudomonas aurantiaca named JD37which with wide-range antibiotic activities(CGMCC.7099). The P.aurantiaca JD37has a widely resistance against pathogen fungal such as Fusarium graminearum、 Rhizoctonia solani、Botrytis cinerea、Sclerotinia sclerotiorum. Meanwhile, JD37also have ability of growth promotion to many monocotyledons, gramineaes, and green vegetations. In this issue, we extracted active ingredient of JD37to analysis the mechanisms of antibiotic activities. At the same time, we applied P. aurantiaca JD37in cole to study the efficiency of biocontrol in greenhouse. Our work laid the foundation for the application of P. aurantiaca JD37. The results show that:1. The fermentation broth of JD37on rape seed germination rate:JD37fermentation broth at higher concentrations is not conducive to rape seed germination, when the dilution≥30times, on seed germination lift. JD37agents can be applied in a rape after emergence or moderately diluted.Effect of JD37on Rape Seedlings:rape seedlings with different concentrations of the JD37fermentation broth processing, combined with research found that the best growth-promoting concentration of JD37on plants is different, for example:the best growth-promoting concentration on Maize and Wheat is about107cfu/g, and the best growth-promoting concentration on Rape is about10cfu/g. Therefore, after dilution, 2. JD37moderate fermentation broth not only can promote the growth of seedlings, but also can play a pest control effect.3. JD37in the the rape rhizosphere and root internal colonization:colonization in the soil concentration of about105-106cfu/g, the concentration of colonization of the roots of approximately103cfu/g, good colonization of biocontrol bacteria play its disease prevention and promoting effects of base, bacteria on rape has a good potential for disease prevention and promoting.4. JD37extraction and separation of antibacterial substances:by the JD37fermentation supernatant extraction, thin layer chromatography, liquid chromatography method to detect the JD37able to generate broad-spectrum antibacterial antibiotics PC A, PC A concentration of its crude sample is about103mg/L. PC A generation of antibiotics, making it a more direct and effective to inhibit a variety of plant pathogenic fungi, bacteria were prepared JD37bio-pesticides can be used for prevention and treatment of crop bacteria.5. Effect of JD37broth in greenhouse control:JD37broth under greenhouse conditions the biocontrol of Sclerotinia sclerotiorum is obviously, the control effect is about82.3%, prevention and treatmentthe effect of talc as a carrier the JD37biological pesticides was66.7%, slightly lower than the bacterial suspension JD37control effect, which may be related to the carrier, protective agent, the storage time, the use of concentration and other related.