| Himetobi P virus (HiPV) is a single-stranded RNA virus infecting riceplanthoppers, which belongs to Cripavirus, Dicistroviridae, Picornavivales. HiPV wasfirst isolated and purified from Laodelphax striatellus Fallen in1992. But, it is notclear so far about strain diversity of HiPV from various geographic host populations,and its infection status in different tissues and developmental stages of Nilaparvatalugens. So a study was carried out on the infection and the influence on its host. Bydetecting HiPV in different geographic populations of rice planthoppers, and thelocation of HiPV in brown planthoppers’ organs and tissues, In addition, looking intothe impact to brown planthoppers(BPH) of HiPV by the method of RNA interference,to make it clear the relationship between the virus HiPV and its one of hosts the BPH.The results were summarized as following.（1）Detection of HiPV in differenct geographic populations of rice planthoppers.After detecting10populations of Nilaparvata lugens,5populations of Sogatellafurcifera and1populations of Laodelphax striatellus collected at different areas inAsia by RT-PCR, HiPV was found in all of the geographic populations of riceplanthoppers. In phylogenetic analysis based on the viral capsid protein sequences,the16virus strains were clustered into four groups with less relevance to the hostgeographic locations.（2）Location the HiPV in organs and tissues of the BPH. Firstly, express thecapsid protein of HiPV in E. coli by building an expression vector ofpGEX-6P-1-HiPV. Preparation the polyclonal antibody of GST-HiPV throughoptimized the expression conditions and purified expression products. Secondly, usethe antibody of HiPV to detect the ovaries, spermaries, midgut, Malpighian tubules,hindgut, salivary glands and fat bodies of the BPH by immunohistochemical staining.Furthermore，detect the relative content of HiPV in these organs and tissues byreal-time quantitative PCR. The results demonstrated that HiPV mainly distributed inthe post part of midgut, followed by Malpighian tubules and hindgut. Spermaries,salivary glands and fat bodies were also infected with HiPV, but at a relatively lowlevel. The Ovaries were almost no HiPV infected with.（3）The proliferation of HiPV in the BPH. Real-time quantitative PCRdetections showed that the relative content of HiPV in the BPH increased graduallyalong with nymph growth and increased sharply after adult emergence. Male adults were infected with more HiPV than female adults.（4）A preliminary study of the physiological role of HiPV to the BPH. Theresearch focused on the subsequent reaction of brown planthoppers and theirdescendants, which were injected the dsRNA of HiPV capsid protein. The resultsshow that after RNA interference, it has no effect on developmental duration of theBPH. The mortality rate of the BPH was not a statistically significant difference.Different stages of nymphs had different reactions toward RNAi of HiPV. Forinterference, the effects were more obvious in3instar nymphs, last longer than othersin4instar nymphs, but not so efficacious in5instar nymphs. As for offspring, it wasdemonstrated that injected the dsRNA of HiPV when the BPH were3instar nymphs,it can affect the content of HiPV in first generation.In conclusion, the paper expound that, HiPV distributed widely in3kinds of riceplanthopper. The relative content in the different tissues of the BPH, the end ofmidgut content of the highest and lowest levels in ovarian. HiPV can reproduce in thebody of the BPH. But it does not affect the normal growth and development of theBPH. The result will provide a base for the further reaserch of the relationshipbetween HiPV and the BPH, which can apply to rice insect resistance or anti-virusresearch. |
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