Characterization of a novel virus infected watermelon in Indonesia based on viral particle using electron microscope

Most of the cucurbits diseases in Indonesia are caused by plant viruses. Tobamovirus is one of the viral genera recently infected cucurbits. The members of cucurbits-infecting Tobamovirus are Cucumber green mottle mosaic virus (CGMMV), Kyuri green mottle mosaic virus (KGMMV), Cucumber fruit mottle mosaic virus (CFMMV), Zucchini green mottle mosaic virus (ZGMMV), and Cucumber mottle virus (CuMoV). A research on the occurrence of cucurbits-infecting Tobamovirus in Indonesia was carried out in 2011. Based on the result, a new characteristic of viral particle were found in watermelon. The viral particle was previously identified as CGMMV based on electron microscope investigation revealed presence of rod-shaped and not enveloped virions. The virions were straight about 300 nm long and 28–30 nm in diameter. However, in some electron micrograph shows rare characteristic of the viral particle. The viral particles could joint each other to bend a new form. Two viral particles were able to joint and formed an angle. Moreover, some of viral particles could joint and form a longer viral particle (800-1100 nm), two to four times longer than CGMMV particle, but the both diameter of the virus are similar. These characteristics indicate that the viral particle is a novel virus, different from CGMMV or other Tobamovirus members.