Interplay Of RSV And RBSDV On The Acquisition And Accumulation By Their Insect Vector Laodelphax Striatellus

Plant viruses which are transmitted by the Hemiptera vectors have commonly caused economic losses to crop production.Rice stripe virus(RSV)and rice black streaked dwarf virus(RBSDV)are both transmitted between rice,wheat and grass weeds through the same vector,small brown planthopper(SBPH,Laodelphax striatellus Fallén),in persistently and propagative manner.According to historical data,rice virus diseases caused by RSV and RBSDV rarely broke out in the field at the same time,and the underlying mechanism has been unclear.This document examines the effects of successive and simultaneous infections of RSV and RBSDV in the same Laodelphax striatellus on the efficiency and accumulation of the virus.The study found that Laodelphax striatellus,after acquiring RBSDV first,its efficiency of acquiring RSV dropped by more than 67%.However,after acquiring RSV first,the acquisition efficiency of RBSDV did not change significantly.Even when the insect is 100% infected with RSV,the acquisition of RBSDV was not affected.Immunofluorescence results showed that the RBSDV acquired first may inhibit RSV from invading the midgut epithelial cells of Laodelphax striatellus,but the RSV obtained first will not affect the invasion of RBSDV.When Laodelphax striatellus feeds on rice plants co-infected by the two viruses,the probability of obtaining RBSDV is greater,and the titer of RBSDV is significantly increased,which may mean that RBSDV replicates higher in Laodelphax striatellus.On the other hand,the titer of RSV showed a trend of first decreasing and then increasing in time.Laodelphax striatellus was fed on rice plants co-infected by the two viruses for 3 days,and only about 5% of the insects were able to acquire the two viruses at the same time,and the acquisition efficiency of Laodelphax striatellus to RBSDV was significantly higher than that of RSV.Although,in general,the efficiency in the transmission of both viruses did not exceed 15%,which shows the low probability that this phenomenon occurs in field conditions.The results of this study help us to understand the behavior of two persistent viruses that interact simultaneously in the same vector insect and give us a vision of why in the field it is rare to find these interactions between RBSDV and RSV.