Effects Of Two Sugarcane Endophytic Bacteria On Sporisorium Scitanmineum

As a tropical cash crop,sugarcane is an important sugar crop and a potential renewable energy material.Sugarcane smut is a worldwide sugarcane fungal disease caused by Sporisorium scitanmineum,which seriously affects the yield and quality of sugarcane and causes great losses to the whole sugarcane industry.Sporisorium scitanmineum can colonize sugarcane after invading from bud,but the traditional chemical pesticide is difficult to enter sugarcane,the control effect is poor,and it is easy to pollute the environment.Therefore,in view of the characteristics that both Sporisorium scitanmineum and endophytic bacteria can colonize in sugarcane,endophytes that have antagonistic or promoting effects on Sporisorium scitanmineum were screened from sugarcane bud.We hope to find a new and efficient method to control sugarcane smut.In this study,by using the flat-panel confrontation method,a strain of endophytic bacteria ZC2-4 has antagonistic effect and a strain of endophytic bacteria D3 has promoting effect on Sporisorium scitanmineum were screened and separated from sugarcane bud.We conducted preliminary exploration on its bacteriostatic substances or promoting substances,and the main research results are as follows:1.Seventy-five endophytic strains of sugarcane were isolated from sugarcane buds and screened by plate confrontation method.There were five strains have promoting effect on Sporisorium scitanmineum and ten strains have antagonistic effect.The D3 and ZC2-4 strains that showed the obvious and stable character were selected.The morphological observation,physiological and biochemical characteristics identification and molecular identification analysis were used to identify the strains.The probiotic bacterium D3 was identified as Rhizobium larrymoorei,and the antagonistic bacterium ZC2-4 was identified as Bacillus amyloliquefaciens.2.The active components in the supernatant of growth-promoting bacterium D3 and antagonistic bacterium ZC2-4 were analyzed.Both strains could precipitate the protein substance in supernatant with ammonium sulfate to obtain the crude extracted active substance.The crude extract was resistanted to high temperature and proteinase K,didn’t conform to the characteristics of proteins.Therefore,it was speculated that the active substances produced by strains D3 and ZC2-4 were lipopeptide.3.Inoculation test of strains D3 and ZC2-4 were carried out in greenhouse.Theresults showed that two sugarcane endophytic bacteria reduced the incidence rate of smut.