Study On Screening And Colonization Ability Of Bacillus In Response To Recruitment Of Maize Root Exudates

Fungal diseases,such as Fusarium moniliforme,Bipolaris maydis and so on,are the main causes of corn yield reduction,in which Fusarium moniliforme will cause a series of problems,such as short fruit size,dim color,insufficient corn kernels,reduced1000-grain weight and so on,which will reduce the yield by 50% to 60% in serious cases.At present,chemical control is the main measure to control corn diseases,but long-term use of chemical pesticides will not only make pathogenic microorganisms resistant,but also pollute the environment,endanger people’s health and destroy the ecological balance.However,the biological control method of plant rhizosphere growth promoting bacteria will not make the pathogen produce drug resistance,and the control effect is good,which is environmentally friendly and maintains the ecological balance.In this study,Xanthomonas oryzae pv,Oryzicola Sclerotinia sclerotiorum,Bipolaris maydis,Fusarium moniliforme were used as targets.The inhibition ability of PGPR was screened through plate antagonistic experiment.The control effect of PGPR depended on its colonization ability in rhizosphere,and chemotaxis,biofilm and mass movement ability were important factors affecting colonization,The detection of bacterial PGPR chemotaxis,biofilm and colony movement ability is the prerequisite for the effective colonization of bacterial PGPR in rhizosphere.This study can provide an effective way for people to use biocontrol fungi to control corn stalk rot disease,and has great significance in the control of plant fungal diseases.The main results are as follows:1.The inhibition of 156 strains on Xanthomonas oryzae pv,Oryzicola Sclerotinia sclerotiorum,Bipolaris maydis,Fusarium moniliforme was determined by plate confrontation method and mycelial growth rate method.51 strains were screened out to inhibit Xanthomonas oryzae pv,40,36 and 33 strains were screened out to inhibit rape Oryzicola Sclerotinia sclerotiorum,Fusarium moniliforme and Bipolaris maydis respectively,and 9 strains were screened out to inhibit Oryzicola Sclerotinia sclerotiorum,Fusarium moniliforme and Bipolaris maydis with 50% inhibition rate.2.The chemotaxis of the candidate biocontrol strains was detected by using the root exudates of Fusarium moniliforme as inducer.The results showed that the chemotaxisindex of OR2-30 strain was 5.67.therefore,OR2-30 strain was selected as the research strain.3.The effects of corn root exudates infected by Fusarium moniliforme on OR2-30 cluster movement ability and biofilm formation ability were further detected.The results showed that corn root exudates infected with Fusarium moniliforme had stronger cluster movement ability and biofilm formation ability to OR2-30 cluster movement ability and biofilm formation ability than normal corn root exudates to OR2-30 cluster movement ability and biofilm formation ability.4.The primers and probes were analyzed by TaqMan qPCR.The primers were compared with oligo6 blast by primer5 and oligo6 blast.The specificity and sensitivity of primers were good.The colonization of OR2-30 strain in the Rhizosphere of normalcorn and the colonization of Fusarium moniliforme infected by Fusarium moniliforme was detected.The results showed that Fusarium moniliforme infection could increase the colonization of OR2-30 strain in the rhizosphere of corn.