ISHS Acta Horticulturae 234: VII International Symposium on Virus Diseases of Ornamental Plants
A STRAIN OF BEAN YELLOW MOSAIC VIRUS IS APHID-TRANSMITTED FROM ORCHID |
| Authors: | J. Hammond, R.H. Lawson |
| Abstract:
A virus disease in Masdevallia orchids was recently reported in Germany affecting orchids imported from the USA; the virus was identified as bean yellow mosaic virus (BYMV) on the basis of host range and serological reactions. Isolation of BYMV has also been reported from Calanthe orchids in Japan. We have isolated BYMV from both Masdevallia and Calanthe, and turnip mosaic virus (TuMV) from one Calanthe, from orchid collections in the USA. Neither BYMV nor TuMV was readily detected by either double antibody sandwich direct or antigen-coated indirect forms of ELISA directly from the infected orchids using polyclonal antisera; detection was improved using appropriate monoclonal antibodies in the indirect ELISA, but best results were obtained with monoclonal antibodies in a dot-blot ELISA on nitrocellulose membranes. The lack of sensitivity of these tests was due to low antigen titer, as the orchid isolates of BYMV and TuMV were readily detected in sap of bioassay plants, and no inhibitory effect of healthy orchid sap was detected. We have demonstrated that green peach aphids (Myzus persicae) are able to transmit BYMV from infected Masdevallia to healthy plants of Nicotiana benthamiana. Transmission was obtained when aphid infested orchids were caged with healthy N. benthamiana but not when aphids were fed upon detached leaves of infected Masdevallia and transferred to N. benthamiana plants. The low virus titer indicated by ELISA results is the probable cause for the difference in transmission when a large number of caged aphids were exposed to test plants for a longer period of time. | |
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