Development of a droplet digital PCR assay to detect and quantify BYDV-MAV and BYDV-PAS in their barley host and aphid vectors

Barley yellow dwarf viruses (BYDVs) belong to a complex of several species, all vectored by aphids. Due to the abundance of Sitobion avenae and Rhopalosiphum padi, BYDV-MAV and BYDV-PAS are among the prevalent species in Irish crops. Several BYDV detection methods, such as immunosorbent assays and PCR-based diagnostic tests, are available and routinely used. However, there are opportunities to develop improved assays to capture viral load information from different sample matrices. Here, we successfully developed a droplet digital PCR assay to detect and quantify BYDV-MAV and BYDV-PAS in both aphid and barley samples. The high specificity shown by this assay allows us to differentiate the two species from each other within a wide dynamic range. This assay will provide a better overview of the process underlying BYDV infection and transmission from the early stage of infection to the appearance of the symptoms.