Study On Induced Activity Of Tobacco Resistance To Pseudornonas Syringae Pv.Tabaci By Harpin Protein From Pseudomonas Syringae

Tobacco wildfire is one of important bacterial diseases in tobacco in the world. Because lack knowledge of resistance, increasing frequency in pesticide application has lead to pesticide residue and environmental pollution, As a result, green barrier is established causing severe economic losses. Harpin protein is nonspecific protein elicitor coded by hrp genes of plant pathogen, and it can elicit hypersensitive cell death (HCD) in nonhost plants and induce resistance to pathogens in many plants. Because harpin has no direct inhibition or toxic effect to the pathogen, resistance and pollution won’t be produced after long-term, large and many use.This study laid the foundation of new production development which is innocuity, no pollution, no resistance and high-efficiency on control of tobacco wildfire disease by harpin protein from Pseudomonas syringae.In this study, induced activity of harpin protein HrpZPsg12and HrpZPsta218from Pseudomonas syringae was measured on resistance to tobacco wildfire.disease Bioactivity and function of harpin proteins from different hrpZ genes were different.Disease decline rate and expand inhibition rate were found out by observation and statistics of tobacco leaf spots for5days,10days and15days after inoculation. Compared with the control, the results showed that there are obvious differences of symptoms relieved between HrpZPsta218supernatant HrpZPsta218precipitations HrpZPsg12precipitation, but there are little different between HrpZPsg12supernatant and HrpZpGEX in the blank vector control group. After15days, decline rates of HrpZPsg12precipitation HrpZPsta218supernatant and precipitation are more than50%, especially that of HrpZPsg12precipitation and HrpZPsta218precipitation reached84.42%and93.51%. Expand inhibition rates HrpZPsg12precipitation and HrpZPsta218precipitation were more than50%, and that of HrpZPsta218precipitation is74.94%.To clear whether protein elicit defense response in tobacco, real-time PCR was use to evaluate gene hsr203and hinl which were signed by HCD expression. The result shows that hsr203of HrpZPsta218precipitation is1.95times than control group, hinl is21.6times than control group. Compared with the HrpZPsg12, hinl of HrpZPsta218precipitation is3.34times than HrpZPsg12. This suggests that treatments by HrpZPsg12and HrpZPsta218elicit defense response in tobacco, but different degrees.From the above, harpin protein HrpZPsg12and HrpZPsta218from Pseudomonas syringae can better control symptom of tobacco wildfire disease by eliciting defense response in tobacco. HrpZPsta218has the most highest activity in precipitation, and it implies wide application foreground in developing of new biological pesticide.