| Wheat yellow dwarf(BYD)is a destructive viral disease in wheat production in China.In the past 60 years,the disease has been epidemic for more than 10 times in the arid regions of northwest China,which reduced the production of winter and spring wheat,and caused serious economic losses.BYD disease is caused by the infection of Barley yellow dwarf viruses(BYDVs)specifically transmitted by aphids.However,after BYDVs infection,the leaves of wheat in the field appear inverted V-shaped yellowing,the plants become dwarf,and the tillers are reduced.As a result,the production and quality of wheat is reduced by BYD disease.In recent years,BYDV-GAV is one of the most prevalent viruses in China,and it has brought a major loss to wheat production in our country.With the popularization and cultivating of novel varieties,there are no report on whether there are cultivars resistant to BYD disease.Therefore,it is an efficient way to control BYD disease by identifying,screening,and promoting wheat cultivars resistant to BYD disease.When plant is infected by virus,the release level of host volatiles will be affected,some metabolic pathways and a series of complex defense responses will be activated,and the virus will benefit itself by regulating defense signal transduction pathways and synthesizing certain defense compounds of plant.Meanwhile,the infection of the host by the virus will affect the selection behavior of the vector to host,and to some certain extent,it will also affect the transmission of the virus by the insect vector.However,interaction between BYDV-GAV,Schizaphis graminum and wheat.During the virus infection process,how does the virus affect the content of volatile substances in wheat remains unknown.Further exploring the interaction between these three items is helpful to propose new ideas and new ways to effectively prevent and control BYD disease,and it is also significant to prevent and control arbovirus diseases.Therefore,in this research,we identified the resistance of wheat cultivars to BYD disease and investigated the influence on selection behavior of vector to host.The main results are as follows:(1)The heap test method was used to identify the resistance of 148 wheat varieties to yellow dwarf disease.The results showed that there were differences in the resistance to yellow dwarf disease among the varieties.A total of 20 varieties resistant to yellow dwarf disease were identified: Bainong 589,Yingman 208,Tianmai 116 etc,accounting for 13.51%;36 highly susceptible varieties: Ruihua 520,Ruihua 523,Ruihua 518 etc,Accounted for 24.32%,other varieties are susceptible.After BYDVs infection,plant height,ear length,flag leaf length,thousand-grain weight,grain protein components,and chlorophyll content of wheat decreased;enzyme activity SOD,POD,CAT content increased.(2)Analyzation of the selection behaviors of the wheat aphid containing virus and wheat aphid without virus to healthy wheat and wheat infected by GAV.Put the Aphids containing virus into two sets of selection devices.The results showed that the selection rates of the aphids with virus for GAV-infected wheat are 25.17% and 29.17%,and the selection rates for healthy wheat are 55.67% and 49.83%,which indicated that the aphids containing virus are more effective.They prefer to feed on healthy wheat which has host selectivity to the poisonous Aphid(p=0.0186).The aphids without virus were put into two sets of selection devices.The results showed that the selection rates of non-toxic aphids for GAV-infected wheat were 31%and 26.33%,and the selection rates for healthy wheat were 37.67% and 38.33%.The nontoxic aphids were independent.The result of independent t test(P=0.0583)showed that the non-toxic aphids had no obvious selectivity for wheat infection.(3)Collect the volatiles of GAV infected wheat,wheat fed by non-toxic aphids,and healthy wheat,then use GC-MS technology for identification and analysis.The results showed that the three types of compounds were released under the three conditions including terpenes,alkanes and green leaf volatiles,among which the relative content of green leaf volatiles was the highest.A total of 48 volatiles were detected in wheat plants infected by GAV;a total of42 volatiles were detected in wheat plants fed by non-toxic aphids;a total of 39 volatiles were detected in healthy wheat.It showed that the types of volatiles in wheat leaves infected by GAV virus are most various,and the relative content of green leaf volatiles is the highest in healthy wheat plants.The expression levels of key genes in the metabolic pathways of green leaf volatiles were analyzed by RT-q PCR,and it was found that the virus infection reduced gene expressions of lipoxygenase(LOX),hydroperoxide lyase(HPL),and allene oxide synthase(AOS).The relative expression level of enzyme gene is consistent with the results of GC-MS analysis.(4)The selection behavior of 3 different green leaf volatiles was verified by experiments using the poisonous aphid.E-2-Hexenal was serially diluted and sprayed on the wheat inoculated with GAV virus.The number of aphids on wheat with different treatment were counted,and the influence of monomer volatiles on the selection of aphids was analyzed.The results showed that when Hexenal was not sprayed,the aphids containing virus tended to feed on healthy wheat,and the selection rate was 56.67%.When the dilution concentration of hexenal was low,healthy wheat was more attractive to toxic aphids;when the spraying concentration of hexenal gradually increased,the attraction of toxic wheat to aphids gradually increased,approaching the attractiveness of healthy wheat.Similarly,in wheat sprayed with E-2-Hexenol gradient dilution,a similar phenomenon appeared in the selection behavior of aphids.Similarly,the gradient dilution of Hexenyl acetate was sprayed on the wheat inoculated with GAV,and it was found that as the dilution concentration increased,the attractiveness of the aphids containing virus to the poisonous wheat was not affected,and aphids containing virus Still prefer to eat healthy wheat.In summary,the selection of varieties with different resistances is to use wheat yellow dwarf resistance resources to speed up the selection and breeding of disease-resistant varieties.The selection behavior of the venomous wheat aphid and the non-venomous aphid on healthy wheat and GAV infected wheat was analyzed.The volatiles of wheat infected with GAV virus,wheat fed by non-toxic aphids,and healthy wheat were collected,and it was found that three types of compounds including terpenes,alkanes and green leaf volatiles were released in all three states.BYDV-GAV infection to wheat increased the release of host volatiles,besides,the types of compounds can affect the selection behavior of aphids.This research provided new thoughts and strategies for preventing and controlling wheat yellow dwarf disease effectively,and it also of significant for the prevention and control of arbovirus diseases. |
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