The Action Mechanism And Application Evaluation Of Biological Vaccine To Rice Stripe Virus

Because of environment pollution and pest resistance to pesticide after extensive use of chemical pesticides in the course of control of rice stripe disease,and rice stripe virus(RSV) will spread quickly by the small brown planthopper (Laodelphax striatellu Fallen),once infect to rice, there is no specific pesticide to inhibit the occurrence of rice stripe disease.Using the latest research achievements of RSV genomics and RNAi technology, the vector, which most effectively interfered with RSV genome, was constructed, and the genetic vaccine was generated. We screened a series of penetrating agents to make the vaccine easily infiltrate into the rice plant by seed soaking and spraying, and the vaccine degraded the CP and SP genes of RSV efficiently, and thus inhibited the expression of RSV and the occurrence of rice stripe disease.Through the vaccine soaking of rice seeds,the results showed that, there is no significant impact to seeds'germination and emergence rate when the concentration of penetrating agents is no more than 1‰;the vaccine can seep into rice seeds and plants under the action of penetrating agents,it could retain in the rice plants for at least 20 days,and the effective duration to RSV and rice stripe disease is at least 15 days, the control effect to rice stripe disease up to 55% by soaking. Summing up all the test results, 1‰A penetrating agent in the vaccine was the optimal concentration of preventing and controlling rice stripe disease by seed soaking.In the research of vaccine spraying,the biological vaccine with appropriate concentration of penetrating agents can seep into rice plants by spraying, its retention time in the rice plants is at least 10 days after spraying one time and the detection rate of vaccine and the adding concentration of penetrating agent are interrelated.It can effectively reduce the relative expression levels of RSV in rice plants by spraying,the effective duration of spraying three times are at least 20 days, the control effect of the vaccine added to 5‰A penetrating agent to rice stripe disease up to 70%. Summing up all the test results, 5‰A penetrating agent in the vaccine was the optimal concentration of preventing and controlling rice stripe disease by spraying.In the research of combination of soaking and spraying, seed soaking by vaccine have a good control effect to rice stripe disease in rice seedlings, and the effect still obviously after 20 days of seedlings; vaccine spraying after rice transplanting to field can further control the incidence of rice stripe disease,the effect duration is at least 10 days.The study concluded that,it can effectively reduce the relative expression level of RSV and control the incidence of rice stripe disease by the combination of soaking and spraying, the effective duration are at least 30 days, the best treatment of combination of soaking and spraying is 1‰A penetrating agent seed soaking combine with 5% A penetrating agent spraying.Comparing the three ways of vaccine seeping into rice plant, the control effect to rice stripe disease by the order from better to worse is: seed soaking combine with spraying >seed soaking>spraying.We compared the vaccine control with pesticide control, the results showed that: the RSV relative expression level of two treatments of combination of soaking and spraying(A2 soaking+A5 spraying,A2 soaking+B5 spraying) and two treatments of seed soaking(A1,A2) are always lower than regent treatment, the incidence of rice stripe disease of three treatments of combination of soaking and spraying(A1 soaking+A5 spraying,A1 soaking+B5 spraying,A2 soaking+B5 spraying),one treatment of soaking(A2) and one treatment of spraying(A5) are always lower than regent pesticide treatment.This showed that combination of vaccine soaking and spraying can achieve a similar control effect with pesticide,and it can be used as a new method of preventing and controlling rice stripe disease.