A Survey of Viruses of Missouri Elderberry with Identification of A New Variant of Tobacco Ringspot Virus (TRSV)

The American elderberry industry of U.S. continues to experience rapid growth, with Missouri leading nationwide interest. Within the last 15 years, elderberry has transitioned from a wild fruit used for homemade jellies and wines to an important specialty crop used in a variety of high-end dietary supplements. Elderberry is a native species and relatively easy to grow. However, we are finding increased pest and disease pressure as concentrated plantings are established, including viral diseases. Information on viruses that infect elderberry is lacking. We collected 400 elderberry samples (both cultivated and wild) from different regions of Missouri and screened for 10 distinct viruses using RT-PCR. Of the 400 samples, 224 and 285 samples tested positive for elderberry virus C (EVC) and D (EVD), respectively. No EVA, EVB and EVE were detected among the samples. Tomato ringspot virus (ToRSV) and Tobacco ringspot virus (TRSV) were confirmed in 36 and 52 samples, respectively, while Blueberry scorch, Arabis mosaic, and Tomato bushy stunt viruses were not detected. High-throughput sequencing using total RNA extracted from eight common elderberry cultivars revealed the presence of a potentially novel variant of TRSV that shows 85% homology to the reference genome sequence in GenBank. An additional screening test specific to this variant resulted in 55 out of 400 samples testing positive. This project will allow us to better understand Missouri elderberry's virus situations and further assist nursery leaders in generating virus-free cuttings for the market.