Abstract:

Wheat yellow dwarf disease,caused by Barley yellow dwarf viruses(BYDVs),is an important viral disease in wheat production.BYDV GAV has become the main pathogen causing wheat yellow dwarf disease.Till now the studies on the function of BYDV GAV encoded proteins P1,P2 and CP are lacking.We focued on the function of P1,P2 and CP,which could lay the foundation for the pathogenic mechanism of BYDV GAV.Phylogenetic analysis of BYDV GAV encoded P1,P2 and CP was conducted using Mega 7.0.We constructed the YFP expression vector of P1,P2 and CP,and then transformed them into GV3101 and infiltrated the leaves of Nicotiana benthamiana.The subcellular localization of P1,P2 and CP was observed using confocal laser scanning microscopy(CLSM).We constructed the biomolecular fluorescence complementation assay(BiFC)vectors of five coding proteins,and then transformed them into GV3101 and infiltrated the leaves of Nicotiana benthamiana.CLSM was used to observe the interaction of P1,P2 and CP and other viral proteins in vivo.Furthermore,we constructed the Potato virus X(PVX) expression vectors of P1,P2 and CP,transformed them into GV3101 and infiltrated the leaves of Nicotiana benthamiana.At 5 days post inoculation(dpi)the symptom formation of PVX infection was observed.The systemic leaves were collected for detection of viral accumulation to determine the effects of the pathogenicity of P1,P2 and CP.Results showed that BYDV GAV was most closely related to BYDV PAV at the nucleotide level.Subcellular localization of P1,P2 and CP was cytoplasm and nuclear.P1 interacted with itself in vivo using BiFC.In the pathogenicity assay,the systemic leaves of PVXCP infection showed chlorosis at 5 dpi,and PVX accumulation was detected,while PVX,PVXP1 and PVXP2 infection showed no symptoms in systemic leaves and PVX accumulation was undetectable,which was detected at 10 dpi,indicating that CP promoted the formation of PVX symptoms.In brief,P1 possibly involves in viral infection via self-interaction in vivo,and CP can promote viral infection.

Key words: BYDV GAV, Localization, Interaction, Pathogenicity