MRNA Differential Display Of Two Nephotettix Cincticeps Groups With Distinct Virus Transmission Competence

Rice dwarf virus (RDV) disease commonly occurred and even ran rampant in rice producing areas in the south of China. It has caused great decreases to rice yields in China. The virus is transmitted by Nephotettix cincticeps in a circulative, persistent manner. On our study, we constructed two groups,one is high affinity virus transmitter group and the other is a low affinity virus transmitter group. We use DDRT-PCR(differential display RT-PCR) to detection of the two groups'genes differentially expressed.After artificially selection, two groups of Nephotettix cincticeps with contrasting virus- transmition efficiency were obtained. Biological assay indicated that the disease incidence rate of rice plants inoculated with the high virus- transmition Nephotettix cincticeps increased to 90.0%, compairing with the 1%- 4% of those inoculated with the low virus– transmition Nephotettix cincticeps. The trasmition rate of F7 derived from the high virus- transmition Nephotettix cincticeps was as high as 87.7% , demonstrating that a high virus- transmition Nephotettix cincticeps group was obtained. However, the high virus transmition competence was only a result of 3 months'selection wihout artificial selection pressure.Whether or not the group of the Nephotettix cincticeps could matain the competence needs further varification.The high virus- transmition Nephotettix cincticeps and the low virus- transmition were investigated using DDRT-PCR for the difference gene expression. We cloned and sequenced seven Segment Segment DD5 belonged to the high- transmition Nephotettix cincticeps ,it was similar to human DNA sequence from clone RP11-459I16 on chromosome 20. Segment DD6 belonged to the high- transmition Nephotettix cincticeps it was similar to P2 protein of RDV. Segment DD8 belonged to the high- transmition Nephotettix cincticeps , it was similar to Drosophila melanogaster Ubiquitin-5E. Segment DD2, DD11, DD3 and DD7 was unknown. They can't be find homologous genes when blasted, We presume they are new genes.