Potato Pathogenic Fungi Antagonistic Bacterial Identification And Its Biological Function Study

In this experiment, The potato wilt(F.tricinctum),Potato Black Bot (C.coccodes),Rhizoctonia disease in potato(R.solani)3kinds of potato pathogenic fungi as target bacteria,screening out aspects of morphology,16SrRDNA gene sequence, biological functions andcharacteristics of antagonistic bacteria have inhibitory effect for the main, the followingresults are obtained.1Screening and identification of antagonistic bacteria disease of potatoFrom103strains of bacteria were screened against40strains of bacteria have inhibitoryeffect on3kinds of potato pathogenic fungi,Through morphological determination and16SrDNA sequence analysis,11strains of B.subtilis，13strains of B.amyloliquefaciens,4strains of B.thuringiensis,3strains of B.methylotrophicus,3strains of B.mojavensis,3strains ofB.tequilensis,B.cereus、B.axarquiensis、Paenibacillus polymyxa isolate each for1strains.2Inhibition ofAntagonistic BacteriaThe4strains of antagonistic strains to3kinds of pathogenic fungi inhibition rate above50%,through antagonistic bacteria processing potato pathogens,vesicles,swelling anddisintegration, emergence of mycelial cells;or cell wall dissolution, hyphal protoplasmleakage, mycelium rupture, digestion.3Promoting effectand dissolved phosphorus of antagonistic bacteriaResults showed that strain IAA secretion，The content of IAA which secretedon culturemedium of King with tryptophan and without tryptophan were31.86ug/ml,20.94ug/ml,20.15ug/ml,23.92ug/ml and20.62ug/ml,16.28ug/ml,6.16ug/ml、10.04ug/ml. Strains O72,O47, S27and Z13of inorganic Ca3(PO4)2has good solubility, but only Z13has dissolvedorganic phosphorus ability of lecithin;Seed soaking and water S27bacteria liquid, cucumber,tomato and cabbage3crop seedling biomass fresh weight and dry weight increasedsignificantly, while O47, O72and Z13respectively on the cabbage, tomato and cucumberwith growth-promoting effect.4Biological characteristics ofAntagonistic Strains4strains of antagonistic bacteria optimum temperature was30℃, the suitable pH=7, andhas the characteristics of high temperature resistance, salt tolerance; successive subculture after20generations has good bacteriostatic effect.5Antagonistic bacteria S27antibacterial substance physicochemical characteristics ofthe crude extract liquidIn3kinds of organic solvent, ethyl acetate extract antibacterial substances of strain S27,inhibition of potato pathogenic fungi rate reached62%; antibacterial substances in crudeextracts at the temperature of30℃, pH=6, the highest antimicrobial activity, and does notbenefit still has good antibacterial activity under the conditions of high temperature, strongacid-base, radiation.Through the above research results,4strains were screened in antagonism, phosphatesolubilization and growth-promoting effect and high temperature resistance, salt tolerance andother characteristics are good, has the good development prospect, for its further developmentof microbial fertilizer and pesticide provides theoretical basis...