Study On Resistance To Cucumber Mosic Virus By Hypersensive Protein

Cucumber Mosaic Virus is a typical member of the genus Cucumovirus of the family Bromoviridae.CMV has a wide range of hosts and can infect 85 families,365 genera,and more than 1,000 plants.CMV is the most popular plant virus in the world and is one of the most economically important plant viruses currently researched.In recent years,with the adjustment of planting structure in China,the planting area of vegetables and fruits in the return season has been expanded,the base number of CMV overwintering is large,and it is getting closer to the tobacco growing area.Cucumber mosaic disease has been increasing year by year.At present,the prevention and control measures for this disease are mainly the cultivation of disease-resistant varieties and chemical control,but the effect is not ideal,and people are paying more attention to pesticide residues,so biological control technology has become a research hotspot in the control of cucumber mosaic virus disease.In the previous period,the laboratory screened a strain of Bacillus subtilis VH-3 with obvious induced resistance to various plant pathogens from the original forest soil of Qinling.Combined with the previous laboratory members on the study of amyloliquefaciens hypersensitivity protein,this experiment found that the presence of a hypersensitive protein in the Bacillus subtilis VH-3 strain that induces plant disease resistance through the cell allergy bad reaction,after strain activation,Liquid protein fermentation,centrifugation and filtration,ammonium sulfate fractionation and other methods were used to extract crude protein,and SDS-PAGE protein electrophoresis and bioactivity determination revealed a supersensitive protein with a molecular weight of about 40 KDa,which was named as SBT1.To determine the control effect of the high-sensitivity protein SBT1 on CMV in Bacillus subtilis fermentation broth.In this study,heart smoke was used as material,and half-leaf method was used to measure the induced resistance of 100,300,500,and 700?g/mL of different concentrations of high-sensitivity proteins to CMV.The results showed that different concentrations of high-sensitivity proteins have a certain degree of Inducing the plant's ability to produce disease resistance,the number of dead spots decreased significantly compared to the blank control and the better the effect as the concentration increased.However,there was no significant difference between 500?g/mL and 700?g/mL.Considering the economic benefits,a high-sensitivity protein with a concentration of 500?g/mL was selected for further testing.The inactivation test of cucumber mosaic virus by a high-sensitivity protein in vitro showed that the hypersensitivity protein does not have in vitro inactivation of cucumber mosaic virus,indicating that the hypersensitivity protein itself does not act directly on the virus,but acts on the plant.Induced its resistance to disease.The 500 ?g/mL hypersensitivity protein with relatively good induction of resistance was used to determine its effect on CMV prevention and treatment.The results showed that compared with the control group,the 500?g/mL hypersensitivity protein had better preventive and therapeutic effects.The earlier the application of high-sensitivity protein,the better the prevention effect.The effect of spraying 48 hours before inoculating CMV can reach 67.75%.The earlier the treatment,the better the treatment effect.The effect of treatment after CMV inoculation can reach 60.53%.The effect of high-sensitivity protein on the activities of defense enzymes POD,SOD and PAL in tobacco were measured.The results showed that the activities of POD,SOD and PAL in tobacco leaves after treatment with hypersensitivity protein were significantly higher than those in the control group,and the overall trend showed a rise.Afterwards,it showed that the hypersensitivity protein could increase the activity of tobacco disease-resistant enzyme and revealed its mechanism of induced resistance.Field trials have shown that hypersensitivity proteins can increase agronomic traits such as plant height,stem circumference,and maximum leaf area.It shows that the hypersensitivity protein can not only induce plants to produce anti-CMV,but also has a promoting effect on tobacco growth,and has broad development and market prospects.