ISHS Acta Horticulturae 234: VII International Symposium on Virus Diseases of Ornamental Plants
VIRUSES IN DIPLADENIA SANDERI |
| Authors: | N. Paludan, M. Heide, J. Begtrup, B. Borkhardt |
| Abstract:
Dipladenia sanderi belongs to the Apocynaceae family and is an attractive flowering pot plant of commercial interest in Denmark. In order to improve the plant material selection was carried out using 38 different clones collected from Australia and Denmark. Virus symptoms, mainly mosaic in the leaves, were registered during the selection. Typical mosaic symptoms were seen in leaves of all the clones and flower symptoms such as colour break and white streaks in many flowers. The symptoms were clearly visible during spring and autumn. Infection trials using sap inoculation were carried out in order to find suitable indicator plants and plants for virus propagation, mainly within the families Chenopodiaceae, Papilionaceae and Solanaceae. Systemic symptoms appeared constantly in Nicotiana benthamiana as a chlorotic mosaic and distortion of young leaves within a period of 4 weeks. In the Papilionaceae family, in Spinach and Catharanthus roseus, mainly latent infection occurred. Local lesions appeared only in Nicotiana megalosiphon and only when virus-infected sap from Nicotiana plants were used as inoculum. Physical properties. Virus-infected sap from Nicotiana benthamiana was used. The virus survived for 10 minutes at 65°C, but not at 75°C, for 8 days at 20°C, but not for 16 days, and a dilution end point was found at 1:10-5. Particle structure and composition. Electron microscopy (EM) of suspension samples from virus-infected Nicotiana benthamiana revived 2the presence of both tobacco mosaic virus (TMV) particles and flexuous poty virus-like particles named Dipladenia mosaic virus (DMV). The DMV was further diagnosed using 43 different antisera to poty-viruses and 12 poty-virus strains by the ISEM technique. Reaction was achieved only to one of three antisera against bean yellow mosaic virus (BYMV). DMV was purified from infected tobacco tissue and an apparent protein subunit molecular weight of 32 KD. The particles contained a single RNA-strand with a molecular weight of about 3 MD. Cytology. Thin sections of DMV-infected tissue carried out by Dr. D. Lesemann, Braunschweig, showed the presence of pinwheels with weakly developed scrolls and/or short curved laminated aggregates, which is not typical for BYMV-infections. Aphid transmission. Successful transmission of DMV was carried out with Myzus persicae feeding for 15 minutes' on infected Catharanthus roseus. DMV was transferred to the Catharanthus roseus as a latent infection and to Trifolium repens causing brown streaks along the veins. | |
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