The Mechanisms For The Different Competence Of Southern Rice Black-streaked Dwarf Virus With Sogatella Furcifera And Laodelphax Striatellus

The spread of most virus depends on insect vectors, which play a key role in the process of virus transmission. Southern rice black-streaked dwarf virus (SRBSDV) is a arboviruses, which was transmitted mainly by white backed planthopper (Sogatella furcifera, WBPH) in a persistent propagative manner. Some scholars found the small brown planthopper (SBPH) can acquire SRBSDV but not transmit it. SRBSDV outbreak showed a trend of increase between 2009 and 2012. Why SRBSDV was spread so rapidly? The endemic mainly because of the high affinity with WBPH and virus from the point of view. Under suitable climatic conditions WBPH can break out quickly, which result in the epidemic of SRBSDV. WBPH can filter with high affinity of the virus population unceasingly. Whether that SBPH is not spread SRBSDV is related to the affinity between the virus and the mediator recognition mechanism and virus co-evolution of insects need further research.The purpose of this paper is to investigate the root which SRBSDV is propagated by WBPH instead of SBPH from the tissue and cell level. Our results will lay the foundation for further exploring the molecular mechanism of virus different affinity. We studied the acquisition and transmission of SRBSDV in WBPHs and SBPHS1 by traditional biology, RT-PCR and immune fluorescence labeling methods. Our results indicated that WBPH was easy to acquire and transmit SRBSDV while SBPH couldn’t transmit it. The primary infection sites of SBPH and WBPH were midgut. The accumulation of virus in WBPH was much higher than SBPH. SRBSDV couldn’t spread to the salivary glands of SBPH and didn’t exist in its hemolymph at 25 days after infection. These results suggested the transmission barrier for SRBSDV in SBPH is the midgut escape barrier. We also studied the infection and spread of SRBSDV in the cultured cells of two vectors. The spread ability of SRBSDV in culture cells of SBPH is poor than that in WBPH. This may not be a breakthrough of SBPH fallen in the gut releases.In summary, we have observed the distribution and diffusion of SRBSDV in insect cultured cells and in intact insects of WBPH and SBPH by biological and immunofluorescence methods. It has resolved the affinity relationship between SRBSDV and its vectors. These studies will provide a basis for further elucidating the mechanism of affinity recognition and provide a new idea for disease prevention.