Research On Function And Application Of Immune Inducing Protein Po3 Of Pythium Oligandrum

Plants grow in nature and they are often attacked by various pathogens.Plants defend pathogens through their own immune systems.Exogenous elicitors can activate plant immune mechanism,and artificial addition of Pythium oligandrum,proteins and other plant elicitors can induce disease resistance in plant immune system.According to the characteristics of plant immune system,scientists developed the elicitors that activate plant immunity.The application of plant immune elicitors to control plant diseases and insect pests can not only reduce the harm caused by diseases and insect pests,but also solve the problems of environmental pollution and the safety of agricultural products.P.oligandrum belongs to oomycetes,which is high efficient in controling fungal and oomycete pathogens,and promote crop growth and yield.P.oligandrum can produce a protein that induces resistance,which is called oligandrin.In this study,we analyzed the culture filtrate of P.oligandrum and identified the oligandrins with biological control potential to provid the basis for the development of plant immune elicitors.We have identified a protein with potential immune-inducing function from the culture filtrate of P.oligandrum,and named the protein Po3.Cloning the Po3 gene into the corresponding vector and transient expression in Nicotiana benthamiana,Po3 could induce an immune response to N.benthamiana.Po3 was obtained by prokaryotic expression,the protein could induce up-regulation of tobacco defense-related gene.For the further study of the Po3 biological control effects,this paper proved that Po3 could improve the resistance of soybean hypocotyls to Pythium ultimum and Fusarium oxysporum;then we demonstrated that Po3 could improve the resistance of N.benthamiana to Phytophthora capsici by leaf inoculation;finally,Po3 was proved to improve the resistance of tobacco to tobacco mosaic virus.For the purpose of investigate whether Po3 have the potential to act as an immune-induced protein,we explored whether Po3 still have activity at different temperatures and pH,the results showed that Po3 still has activity at 50℃ and at the interval of 2-9.5 in pH.In this study we explored the induced temperature of Po3 and demonstrated that Po3 could be induced at 28℃.Then we carried out the protein spray soybean experiment at the Baima base of Nanjing Agricultural University,and counted the biomass of soybean.The results showed that the hundred-grain weight and yield of soybean were increased after spraying Po3.We hope that the research in this paper will provide new materials for the research and development of plant immune elicitors,and also provide new method for the control of plant diseases.