Abstract
A sap transmissible virus was isolated from a mulberry tree showing both ringspot and filiform-leaf symptoms. Soybean, cowpea, pea, bean, Chenopodium quinoa, Nicotiana clevelandii and sesame were infected with this virus by sap inoculation. Infectivity of the crude sap was lost by heating at 50-60°C for 10 minutes, by aging at 15°C for 3 to 5 days, and by diluting at 103-104. The virus was transmitted through seeds of soybean, but not transmitted by the aphid, Myzus persicae. When preparations from diseased mulberry leaves were examined under electron microscope using dip method, spherical particles of about 22nm in diameter and elongated particles of about 730nm in length were found, whereas only spherical particles were found in the preparations from infected herbaceous plants. Nine collections of mulberries showing enation, ringspot, filiform-leaf, mosaic and yellows symptoms were tested for the identification of the causal virus by sap inoculations to test plants and by dip method under electron microscope. The sap transmissible virus and the elongated particle were found in all collections. The spherical virus was purified by clarification of homogenized cowpea leaf tissues with carbon tetrachloride, followed by differential centrifugation and sucrose density-gradient centrifugation. Electron microscopic examination of purified preparation showed spherical particles of about 22nm in diameter. Antiserum to the virus did not react with cowpea mosaic virus, tomato ringspot virus, and satsuma dwarf virus. Tubular inclusion bodies containing single rows of spherical particles and characteristic vesicular inclusion bodies were observed under electron microscope in ultra-thin sections of cowpea and mulberry leaves infected with the virus. Healthy mulberries (vars. Hachijo and Kairyo-Nezumigaeshi) were inoculated with the partially purified virus obtained from diseased cowpea leaves by sap inoculation. After 3 to 6 months from inoculation, 4 of 24 inoculated mulberries either showed symptoms of ringspot and mosaic or proved to be infected latent. It is inferred that the virus belongs to NEPO virus group, and the name mulberry ringspot virus is proposed. The nature of the elongated particles remains obscure.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
