The Role Of Sperm Protein Vigilin In Vertical Transmission Of RGDV

In recent years,the epidemics of rice gall dwarf disease have became the main virus disease in rice planting area,Hainan,Guangdong,Fujian Province,southern China,which also caused a serious threat to agricultural production of rice.Rice gall dwarf virus(RGDV)belongs to the genus of Phytorevirus in the Family Reoviridae,which is mainly transmitted by Recilia dorsalis in a persistent propagative manner.Currently,researches mainly focus on the infection route,replication and spread of RGDV in its vector.Immunofluorescence and electron microscopy showed that RGDV viral particles are mainly adhered to sperm surface.In our previous study,we have got nine proteins that possibly interacted with RGDV P8 by GST pull-down assay,including high density lipoprotein binding protein(vigilin),Calreticulin,Lipophorin precursor and other candidate proteins.In this study,we verified the interaction between the nine proteins and RGDV P8 by yeast two-hybrid technique and found that only vigilin could interact with P8.We further proved that vigilin could interact with RGDV P8 in vitro by using GST pull-down and co-immunoprecipitation assay.Results from RT-qPCR and western blot assay showed that vigilin has a higher expression level in testis than other tissue Recilia dorsalis.Interestingly,the expression of vigilin was positively correlated with the transcript level of RGDV.When treated with the systhesized double strand RNAs of vigilin gene,the expression of vigilin in Recilia dorsalis was significantly suppressed and the viral titer was also decreased significantly compared with that of control treatment.Additionally,the expression of vigilin in testis was also decreased significantly.Therefore,we think that vigilin may affect the proliferation of RGDV by interacting with P8 in the testis of Recilia dorsalis.In a conclusion,this study demonstrated the interaction between RGDV P8 and vigilin protein of Recilia dorsalis testis.Because male Recilia dorsalis can transmit RGDV by mating with female insects,and then transmitted to offspring by female insects.We have proved that the relative expression of vigilin in testis is higher than in other tissues,so vigilin may facilitate this process in Recilia dorsalis.These results have provided a new evidence for further study the vertical transmission mechanism of RGDV by Recilia dorsalis.