The Study Of Rice Black-streaked Dwarf Virus Coat Protein-mediated Antiviral Mechanism

Rice black-streaked dwarf virus(RBSDV)belongs to the group 2 of the genus Fijivirus species within the family Reoviridae and its main insect vector is Laodelphax striatellus(SBPH).The symptom of plants infected with RBSDV mainly exhibit plant dwarfing and leaf color deepened.RBSDV lead to rice black-streaked dwarf disease in rice and maize rough dwarf in maizes,which cause serious damage to the grain production in our country.Previous studies indicated that RBSDV was a double-stranded RNA virus with 10 genome segments(S1-S10)and encoded a total of 13 proteins,of which P10 encodes the coat protein of the virus.Viral coat protein plays important roles in all processes of plant virus infection.Previous studies suggested that P10 coat protein could localize on the endoplasmic reticulum(ER)and trigger the ER stress response in Nicotiana.benthemina.However,little information is known about the role of P10 coat protein in RBSDV infection.Here,we report the function of P10 coat protein in virus infection in its host rice.In our study,we focus on the function of P10 protein in rice and the role of P10 in virus infection.The results revealed that expression of P10 in rice resulted in plant development abnormal,such as reducing plant height,increasing tillering and reducing grain number of grain in P10 transgenic rice.These results suggested P10 could affect the plant growth and development.Virus inoculation by SPBH showed that P10 transgenic rice could significantly reduce the titre of RBSDV virus and reduce the incidence of virus than control plants.These results indicated that P10 make more resistant to RBSDV infection.Our results showed that expressing the P10 mutant P10RNA in rice(P10 only transcribed RNA,but no protein was translated)did not increase the resistance to RBSDV,indicating that P10 protein plays a prominent role in rice resistance to RBSDV but not P10 RNA.That the ability of P10 increased RBSDV resistance in rice promoted us to explore whether P10 transgenic was resistant to the Southern rice black-streaked dwarf virus(SRBSDV).Interestingly,virus inoculation by white-backed planthopper(WBPH)showed that P10 transgenic rice can effectively reduce the content of SRBSDV and disease incidence.RT-PCR analysis showed that both SRBSDV and RBSDV were not found in the same plant.SRBSDV was only found in rice that had not been infected by RBSDV.These results indicate that RBSDV has antagonistic interaction and homologous exclusion with SRBSDV,and the coat protein P10 may play a pivotal role in both viruses interaction.