The development of a multiplex PCR for the detection of three zucchini viruses

One of the most important threats for zucchini (Cucurbita pepo) production in temperate and tropical growing regions are virus diseases. The most common viruses are Cucumber mosaic virus (CMV, Cucumovirus), Zucchini yellow mosaic virus (ZYMV, Potyvirus) and Watermelon mosaic virus (WMV, Potyvirus) which are transmitted in a non-persistent way by aphids. The symptoms caused by these viruses, including mosaic, mottling, chlorosis and leaf distortion result in a decrease of production and, in case of severe infection, in unmarketable products due to fruit distortion. However, a high similarity in symptoms between the different viruses impede identification of the viruses in the field. Currently, detection is carried out by ELISA or RT-PCR, yet both of these methods have important limitations. Examples are a reduced sensitivity and cross-reaction for ELISA or specificity problems and for RT-PCR. Additionally, no reliable multiplex PCR method is available currently, raising the costs as three parallel PCR reactions are required. In order to reduce labour and consumption of consumables, a sensitive and specific multiplex PCR for the detection of CMV, WMV and ZYMV was developed. This multiplex PCR allows the detection of these viruses in plants infected with a single virus as well as in plants that are infected with a combination of viruses without cross reaction occurs. This method will be used to study the epidemiology of zucchini viruses in Flanders, but can also be used in future survey programs to screen high numbers of samples at reasonable costs.