Cross Protection From Mild Vaccines Derived From Cucumber Mosaic Virus Against Virus Diseases Of Tobacco And Tomato

The occurrence of plant virus disease is more and more wide,which not only harms crops,but also becomes a major class of diseases that harm the vegetable industry in China,leading to heavy losses of agricultural economy.The cross-protection strategy of mild virus vaccine is an effective measure to control plant virus diseases.Cucumber mosaic virus(cucumber mosaic virus,CMV),with the characteristics of broad host and multiple fraction,is suitable as the ideal basic carrier for the creation of mild vaccine.In this study,based on the detection of tobacco virus disease in the field in 2021,we selected the mild vaccine with CMV as skeleton as experimental materials,selected the vaccine with good stability and cross-protection effect on tobacco indoors,and applied it to the evaluation of tobacco virus disease in the field;and analyzed the application potential of mild vaccine for tomato virus disease prevention,so as to provide data for the creation and application of CMV as skeleton.Based on the naturally occurring tobacco virus diseases detected in Weifang tobacco area in 2021,seven bivalent mild vaccines with CMV as the framework of the three viruses and four quadrivalent mild vaccines targeting the three viruses were selected as research objects to evaluate the vaccine stability and cross-protection effect indoors.The results showed that bivalent mild vaccine for the target virus PVY:R2-PVY-200II,bivalent vaccine for the target virus TMV:R2-TMV-200I,bivalent vaccine for the target virus TVBMV:R2-TVBMV-200I、R2-TVBMV-200II,and tetravalent mild vaccines:R2-2b PTⅢ-T_MPT_V、R2-2b PTⅢ-T_MT_VP、R2-2b PTⅢ-PT_VT_M、R2-2b PTⅢ-PT_MT_Vwere stably inherited in tobacco,it can be used as candidates for mild vaccine prevention and effect use in the field.According to the above mild vaccines,selecting three bivalent mild vaccines and two terivalent mild vaccines,as well as two satellite RNA species(sat CMV-TA-ca and sat CMV-TA-tb)acting as vaccine modulators,and eight vaccines were combined in Weifang high dense tobacco area,respectively CM/PVY single agent(group(1))、CM/TMVsingle agent(group(2))、CM/PVY+CM/TMV mixture(group(3))、CM/PVY+CM/TMV+CM/TVB mixture(group(4))、R2-2b PTⅢ-T_MPT_Vsingle agent(group(5))、R2-2b PTⅢ-PT_VT_Msingle agent(group(6))、R2-2b PTⅢ-T_MPT_V+sat CMV-TA-ca mixture(group(7))、R2-2b PTⅢ-T_MPT_V+sat CMV-TA-tb mixture(group(8))。After tobacco transplanting,the types of naturally occurring tobacco virus disease and the tobacco disease index were investigated in the field,so as to comprehensively evaluate the vaccine prevention efficacy in the field.The naturally occurring tobacco viruses detected in high-density tobacco areas in 2022 were CMV,TVBMV,PVY,PVX and TMV,and the detection rates of CMV and TVBMV were as high as87%and 85%,respectively.The treatment of attenuated vaccines had a good cross-protection effect on field tobacco virus disease overall,and the average control effect of the two field investigations was 25.10%and 26.98%;however,there are some differences in the same vaccine treatment groups during the growth period and between the vaccine treatment groups,the relative efficacy of treatment group(3)(CM/PVY+CM/TMVmixture)in the vaccine group was 33.83%and 32.44%,respectively,and the prevention effect was the highest among the eight vaccine treatment groups;the relative efficacy of treatment group(2)(CM/TMPTV+sat CMV-TA-Tb mixture)in the two surveys in different growing periods was 11.22%and13.37%,respectively,which was lower than the average relative effect of the vaccine with the worst effect.Five different types of CMV infection clones were used to inoculate"Zhongshusihao"(large fruit type)and"Huangshengnv"(small fruit type)tomato.The results showed that five CMV infection clones could systematically infect tomato plants,which suggested the possibility of CMV to create mild virus vaccine in tomato.In addition,the mild vaccine(R2-TMV-200 I)was selected to observe the cross-protection effect on the tomato,the results5showed that the best effect against skeleton virus CMV,the average effect of the two types of tomato reached about 70%;the control effect on the target virus TMV is the second,with the average control effect reaching about 60%;the non-target virus PVY has the cross-protection effect of about 30%.In this study,the protective efficacy of weak vaccines in tobacco indoors and in the field and on tomato,provided new research materials and control strategies for the against of plant virus diseases.