Investigation Of MRNA Expression Of RSV Genes In Hosts

In order to understand the changes of Rice stripe virus (RSV) coding genes (RdRp,NS2,NSvc2,NS3,CP,SP and NSvc4) in mRNA expression levels during the replication of the virus, seven specific primers were designed based on all sequences of RSV in GenBank. The relative mRNA expression level of RSV 7 genes in rice suspension cells were investigated by real-time reverse transcription PCR. These 7 genes of RSV could be detected at various time (0h,12 h,24h,36 h,48h and 60 h) post infection with RSV in rice suspension cells. The mRNA expression of RdRp gene reached its peak at 12 h after RSV infection, and increased 44.07 times than that of primary inoculation. However, the mRNA expressions of others genes of RSV reached their peaks at 48h post-infection, and increased 20.08,9.92,10.99,139.14,49.19 and 0.54 times in comparison with those of primary inoculation respectively. These results indicated that the RdRp gene play an important role in the replication of RSV, and the replication of RSV reached its peak at 48h after inoculation in rice suspension cells. The variabilities of RSV 7 genes in the course of RSV replication were analyzed by the method of t-test. And disclosed that the negative sense coding genes (RdRp,NSvc2 and NSvc4) showed more difference with significance except for CP gene in the RSV replication course. RdRp gene showed most difference with significance, and the value of t-test was 2.67 (P=0.05～0.025). However, CP gene showed most difference without significance, the value of t-test was 1.35 (P=0.40～0.20). All of positive sense coding genes (NS2,NS3 and SP) were proved more difference without significance.Rice stripe virus (RSV) is transmitted in persistent propagative manner by Laodelphax striatellus, but relative little is known about the gene expression features of RSV and its vector that permit their interaction in nature. To determine the possible genes whose expression profiles might reflect the virus-transmission competence. In this study, we first screened three types L. striatellus with significantly different transmission competence for RSV, high efficiently transmitting population (HETP), little efficiently transmitting population (LETP) and nontransmissible viruliferous population (NTVP) with the inoculative rates at 95%, 5%, and 0, respectively. Then, the different relative mRNA expression of RSV coding seven genes from individual female L. striatellus of three types vectors were determined using real-time reverse transcription PCR. Results show that the RSV transmission competence of L. striatellus may be regulated by high selection pressure of RSV and inherited from the predecessors. And the expression of NSvc2 and NSvc4 genes were associated with the RSV transmission competence of L. striatellus. The SP gene expression of HETV and LETV exhibit most significantly different as comparison with that of NTVV. NS3 gene shows more stable expression among three types vector. The results of this study will aid in the design of transmission and pathogenesis studies involving Tenuivirus.