Revealing The Interactions Of Barley Yellow Dwarf Virus-Vector Sitobion Avenae-Wheat

Barley yellow dwarf viruses(BYDVs)are phloem-limited luteoviruses that infect most members of the Poaceae family including wheat(Triticum aestivum L.),barley(Hordeum vulgare L.)and oat(Avena sativa L.).BYDV is most efficiently transmitted by Schizaphis graminum(Rondani),Sitobion avenue(Fab.),Rhopalosiphum padi L.and R.maidis(F.)in China.BYDV and its vector insects are always found in field together.Wheat cultilar resistance is an especially advantageous,efficient and environmentally friendly way to controlling BYDV and aphids.I used natural aphid infestation to evaluate the resistance of 36 wheat varieties(lines),which were from abroad,and found that KOK,KOK IPPCAS,Astron,tp19 and Amigo-6 are not only resistant to aphids and BYDV,but alos to BYDV.PI137739,PI262660,PI294994 and 98-10-30 are reisistant varieties(lines)to S.avenge,but not resistant varieties(lines)to BYDV.Tm and Tam200(13)G are susceptible varieties(lines)to S.avenae,but prevent BYDV development in field.Xiaoyan6,186Tm10,98-10-35q-9 and 186tm39 are susceptible varieties both to aphid and BYDV.Used hill plot technique,the resistance of 197 varieties(lines)and germplasms to BYDV was evaluated.Nine varieties(lines)were considered as high resistant.11 varieties(lines)were identified as high susceptible.12 varieties(lines)could not prevent the vector transferred virus,but could prevent the BYDV symptom(severity)development.These disease incidences were greater than 80%,but disease indexes were lower than 4 grade,14 varieties(lines)could prevent the vector transferred virus,but could not prevent the BYDV symptom(severity)development.These disease incidences were less than 60%,but disease index was higher than 4 grade.The tripartite interactions in a wheat-Sitobion avenae-barley yellow dwarf viruses(BYDV)pathosystem,and the varieties(lines)resistance influence on the interactions had been studied on three wheat varieties(lines)under field conditions for two consecutive years.The results demonstrated that:(1)aphid peak number(APN)in the aphid + BYDV(viruliferous aphid)treatment occurred greater and earlier than that in the aphid(non-viruliferous)treatment.The APN on a S.avenae-resistant cultilar 98-10-30 was significantly lower than on two aphid-susceptible varieties Tam200(13)G and Xiaoyan6.(2)The production of alatae(PA),BYDV disease incidence(DIC)in the aphid + BYDV treatment was greater than that in the aphid treatment on 98-10-30,but not on Tam200(13)G and Xiaoyan6.(3)The PA and DIC on 98-10-30 were greater than those on other two varieties in both years,and the disease index(DID)on Xiaoyan6 was greater than that on Tam200(13)G in the aphid + BYDV treatment in 2012.The DIDs on 98-10-30 and Xiaoyan6 were greater than on Tam200(13)G in the BYDV treatment in both years.(4)Yield loss in the aphid + BYDV treatment was greater than that in the aphid or BYDV treatments.The BYDV or aphid + BYDV treatments caused greater yield losses on 98-10-30;the aphid + BYDV treatment resulted in greater yield loss than either the aphid or the BYDV treatments on Tam200(13)G.We concluded that aphid infestation and BYDV infection promoted each other under field conditions.The viruliferous aphids caused greater yield reductions than non-viruliferous aphids or virus alone.The wheat cultilar resistance affected the aphid dispersal,virus transmission,and wheat yield loss obviously.98-10-30 prevented aphid population from increasing,but increased PA,and accelerated BYDV spread when infested by viruliferous aphids,Tam200(13)G could prevent the BYDV symptom(severity)development,but not BYDV spread.I used the multiples PCR technique,found the BYDV isolation,named as BYDV-GAV-12YL,belong to BYDV-GAV species.The complete genome sequences identify and open read frame(ORF)was analysised.It was found that BYDV-GAV-12YL was closed to BYDV-GAV-YL4(GenBank No.is KF52338).There was lower homology between different strains,but higher homology within GAV strain.The biological process and molecular function was predicted for the proteins coded by ORF of BYDV-GAV-12YL isolation.We guessted the biological process and molecular function of protein coded by ORF1 were binding,localization,and transport.It maybe related with the infection and diffusion of BYDV.The sequence identity of CP-RDT protein coded by ORF3 + ORF5 was 16.33%with the sialidase of Trypanosoma rangeli.We guessted it related with vector recognition.The function of protein coded by ORF6 possbile was signal response related with transport.