P-165 - Development of duplex RT-qPCR assay to discriminate blueberry virus S from blueberry scorch virus

An infectious cDNA clone of a novel carlavirus from blueberry, blueberry virus S (BluVS) was identified and developed recently. BluVS shares identical genome organization, similar serological properties, and symptomology with blueberry scorch virus (BlScV). More importantly, both viruses can cause total crop loss. Here, we obtained sequence information from additional isolates of BluVS and BlScV. This information, along with BlScV sequences available in the GenBank was used to develop a duplex TaqMan probe-based quantitative PCR assay to detect and discriminate BluVS from BlScV. The newly developed assay detects BluVS isolates and discriminates representative BlScV isolates from each of the major virus clade. An extensive survey is underway to determine the distribution of BluVS and BlScV on major blueberry growing regions in the United States. The availability of this new assay improves the current diagnostic protocol for these viruses, further strengthens the certification standards and release of high-quality virus-tested planting materials to the blueberry industry.