Antifungi Activity And Antifungi Substance Of Nightshade Plants Endophytic Bacteria

Plant diseases are one of the main factors to disturb agricultural production,in recent years,vegetables are infracted severitily by plant diseases as dependency vegetable's develop and crop system's regulate. Epidemic disease,virus disease,bacterial wilt and other main plant diseases can make losses to nightshade vegetables' production. Chemical pesticides are the main measures to control plant disease presently,which can make environmental pollution,pathogens drug-resistant and do harm to non-target organisms.Abundant of research showed that there are plentiful of endophytic bacteria existing in plants bodies which show good efforts to plant diseases,which has become the hotspot in Plant Pathology.There will be good future for endophytic bacteria in Plant Pathology,for their good effort and variety of biological functions to plant diseases.By separating endophytic bacteria from nightshade vegetables,this study screens antagonistic bacteria which can colonize in plant favorably and do good in promoting health and disease prevention.To these endophytic antagonistic bacteria,we study their antibacterial substances and the relations of antagonism and endogenous.For these research,we can provide a theoretical basis to the research of endophytic bacteria. The results are as follows.1.There were 149 endophytic bacteria separated from nightshade vegetables,while 47 were from roots,56 were from caudexes,33 were from leaves and 13 were from fruits.We screened 18 antagonistic bacteria showed good efforts to Verticillium dahliae,Fusarium oxysporum,Alternaria solani,Phytophthora capsici,Rhizoctonia solani, Alternaria alternata,Bipolaris sorokiniana and Alternaria sp.from those 149 endophytic bacteria. 2.With the observation of figuration characters,the physiological and biochemical tests,we found that most of these antagonistic bacteria were Bacillus sp.,the percent was 55.6%.Left strains were Pseudomonas sp.and Xanthomonas sp.Combined the 16S rDNA gene analysis of strain L-6,we identified L-6 to be Paenibacillus polymyxa.There was no report to isolate Paenibacillus polymyxa from capsicum,and we are the first.3.We Used the measure of Drug-resistant marker to strain L-6 in order to study its endogenous.By the study of watering roots and soaking seeds of capsicum,we found strain L-6 can colonize in roots, caudexes and leaves,and maintain aconsiderable number for a long time fre the colonization number reduce less in 10 days.4.The suspension of strain L-6 can promote capsicum roots' elongation evidently,improve the activity of peroxidase(POD) in capsicum body and the activity of superoxidedimutase(SOD) in capsicum roots.5.The broth of strain L-6 can show good inhibition to the growth of mycelium and the bourgeon of spores of Fusarium oxysporum and Alternaria solani et al.,which made the mycelium become contorted and abnormality and even the mycelium's cell wall ablated,reduce the bourgeon of spores.6.The results of thin layer chromatography(TLC) and UV detection showed that L-6 strain's active substance has the absorbing peaks steady in 323nm.By study its characters,we found that L-6' active santibiotics showed good heat resistance,good antibacterial stability and weak anti-UV stability.