Induced Resistance To Low Temperature And Plant Disease By Bacterial Fermentation Fluid For Soybean

The low temperature is the key factor to reduce the yield, along with soybean root rot disease and nematodes causing serious harm. The bacterial strains that could induce the soybean to generate resistance to low temperature,pathogen and nematodes were selected through repeated screening laboratory and field. The effective strains of bacteria were systematically studied in terms of classification, fermentation condition, biocontrol effect. The purpose of this research was to develop a more effective and novel method to help the soybeans to resist anti-adversity. Results were shown as follows:1. Soybean seeds coated by 150 bacterial strains were grown in greenhouse which was in cold treatment,then these seeds were grown on farmland which Heterodera glycines occurred seriously in Liaoning and Heilongjiang province. After 35 days,4 strains showed efficiency to resist adversity after Heterodera glycines, root rot incidence survey and maturity yield monitor. Four bacterial strains that induced soybean system resistance were screened from farm and greenhouse experiments. They were Sneb69, Sneb82, Sneb179, Sneb218, and Sneb69,which showed strong and stable resistance between them.Sneb69 not only can induce to resist cold stress but also can induce to control Heterodera glycines.2. Four strains of bacteria were classified and identified by the methods of classical morphological, biochemical and molecular biological taxonomy. The sequences of 16SrDNA gene were sequenced and analyzed. Results showed strains Sneb69, Sneb82 and Sneb218 belonged to Bacillus megaterium, and Sneb179 belonged to Pseudomonas aeruginosa.3. Breeding of high-production strains and their fermentation conditions were optimized. The fermentation conditions were investigated by single factor and designs of orthogonal experiments. Results were shown as follows:the liquid medium of fermentation of strain Sneb69 constituted by fructose 0.9%, beef extract 2.1%, yeast extract0.6%. The fermentation conditions included the optimum initial pH6.5,2% of the inoculation amount, the volume of medium in shaking flasks about 30ml/100ml flask, rotate speed about 150r/min, all light cultivated at 28℃. The liquid medium of fermentation of strain Sneb179 are constituted by sucrose 3.0%, beef extract 3.0%. The fermentation conditions included the optimum initial pH5.5,2% of the inoculation amount, the volume of medium in shaking flasks about 20ml/100ml flask, rotate speed about 150r/min, and all light cultivated at 28℃.4.The effects induced by application of fermentation results have shown show that the laboratory test proved that the Sneb69,Sneb82,Sneb179 and Sneb218 fermentation of four strains of soybean of soybean can produce a strong resistance. Sneb82 and Sneb218 can control soybean cyst nematode and root rot fungi, and Sneb179 can induce soybean to resist low temperature, and Sneb69 can induce soybean to resist low temperature of those that have good prospects.