Study On Biological Characteristics Of Papaya Ringspot Virus Luohanguo Isolate And Preparation And Application Of Antibodies Against The Virus

Siraitia grosvenori (Luohanguo) viral disease was co-infected by Papaya ringspotvirus (PRSV), Zucchini yellow mosaic virus (ZYMV) and Watermelon mosaic virus(WMV). PRSV Luohanguo isolate (PRSV-LHG) separation, propagation, purification,biological characteristics and polyclonal antibodies preparation were conducted in thisstudy. PRSV-LHG polyclonal antibodies were used for detected different plants in thefield to confirm the viral host range. The results showed that PRSV-LHG could beseparated by Luffa cylindrica from diseased leaves of Luohanguo. Cucurbita pepo wasused for propagated PRSV-LHG. Among host plants detected, PRSV-LHG could infectCucurbita moschata, C. pepo, L. cylindrica of Cucurbitaceae and Chenopodiumamaranticolor of Chenopodiaeeae. But it could not infect Lagenaria siceraria, Benincasahispida, B. hispida of Cucurbitaceae, Datura stramonium, Lycopersicon esculentum,Capsicum annuum of Solanaceae, Vigna sinensis, Pisum sativum, V. unguiculata ofLeguminosae, Brassica pekinensis and Raphanus sativus of Cruciferae. The dilution endpoint of PRSV-LHG was 10^-2. Its longevity in vitro was 20 days. The thermalinactivation point was between 50℃～55℃. Aphid could transmit PRSV-LHG.PRSV-LHG was purified from diseased leaves of C. pepo and the purification yield was2 mg virus per 50g diseased leaves. PRSV-LHG particles were flexuous under theelectron microscope. The polyclonai antibodies against PRSV-LHG were prepared byinjected rabbits with purified virus particles. The titer of this antiserum was 1:64 000.The crops and weeds in or nearby the Luohanguo orchard were detected withPRSV-LHG polyclonal antibodies. The results showed that 54 specimens of 22 speciesplants in 21 genuses in 13 families were reacted positively with the antiserum, in which18 specimens belong to Cucurbitaceae, accounting for 1/3 in these positive plants. Otherpositive plants were Viola verecunda of Violaceae, Malvastrum cormandelianum of Malvaceae, Alternanthera sessilis of Amaranthaceae, Phytolacca acinosa ofPhytolaecaceae, Amphicarpaea edgeworthii of Leguminosae, and Clerodendrumcyrtophyllum of Verbenaceae. These plants may be the other hosts of PRSV-LHG.Among these plants, only S. grosvenori and C. cyrtophyllum showed viral diseasesymptom. Other plants had no visible symptom.