Study On The Active Substance Of Bacillus Sp.AMCC100018 Against Meloidogyne Incognita

Root-knot nematode?RKNs?are an organism of plant pathogens,which has the features of a broad range of hosts,simple transmission channels,significant hazards,and difficulties in prevention and control.RKNs can invade the roots of crops,block their absorption of nutrients,for example,water and fertilizer.It will make the plant shorter in the early step,and the immunity will be decreased in the first stage.In the later step,it will reduce crop yields,extinction,and even death.Hence,it has severely jeopardized the development of agriculture in China.Bacillus sp.AMCC100018 is a biocontrol strain screened by our laboratory with high efficiency against southern RKNs.This research first confirmed the stability of the nematicidal activity of Bacillus sp.AMCC100018.Later,the laboratory was isolated and purified,and the active substance was investigated and compared by mass spectrometry to check the standard's nematicidal activity.Principally reached the following research outcomes:The LB fermentation broth of Bacillus sp.AMCC100018 has extremely effective nematicidal activity,and its maximum value can be obtained after 48 hours of fermentation.The nematicidal activity of the fermentation broth of the strain comes with generational stability,high-temperature resistance,acid and alkali resistance,and can not be enzymolysis by protease so that it can be saved under the light for a long time.The four organic solvents,which include n-butanol,ethyl acetate,chloroform,and trichloromethane,cannot effectively extract active nematicidal substances,Therefore,nematicidal active substances are water-soluble ingredients.Furthermore,four macroporous adsorption resins,two cation exchange resins,and two anion exchange resins were screened.Meantime,these eight resins were unable to adsorb active nematicidal substances effectively.Moreover,XAD1180 and XAD16N resins were adopted to pretreat the fermentation broth.Next,chromatographically pure white material was reached by RP-C18,Sephndex,and preparative liquid phase technology.Besides,it employed a TLC color reaction and infrared scanning and estimated that as a peptide or an amide.The separated active substance was investigated and compared by LC-MS,and the compounds were presumed to 5-aminolevulinic acid,Gly-l-pro and Prolylglycine.After identifying the standard product's nematicidal activity,wherein 5-aminolevulinic acid had the activity of killing southern RKNs with a 24-hour LC₁₀₀00 of 0.8mg/mL.