2018 ASHS Annual Conference

Rose rosette virus (RRV) is a negative sense, single stranded RNA virus. The host for RRV is roses of all classes, as no resistant variety has been identified. Rose rosette disease (RRD) has been a problem in the United States for about 20 years; however the virus was only identified as the causal agent in 2011. Because RRD is a viral disease, there are no known treatments for infected plants. Thus, management requires that infected plants are removed from the landscape slow the spread of the disease. Currently the most accurate way to diagnose a rose with RRV is through Takara Reverse Transcription qualitative PCR (qPCR). However, as this is a costly system, the most common molecular diagnostic for the virus is with Reverse Transcription PCR tests. Unfortunately, there have been many issues with false negative results. This study compared the eight primers developed for 4 of the 7 segments of the Rose rosette virus genome to determine which of these primers is the most effective for the two common diagnostic methods. Samples used in comparison were collected from various parts of Texas along with numerous out of state samples. When comparing the five available qPCR primers for RRV, it was found that primers developed for the third viral segment were the most sensitive for RRV detection. RRV2, which is a primer developed in Oklahoma, was found to be the most sensitive for qPCR detection. When comparing the three available primers for RT-PCR, it was found that the RRV3 primer, from Minnesota, developed for the third viral segment was the most sensitive. The two primers are in different locations on the third segment, but there is little difference in their detection capabilities. The eight primers tested come from four different states and while there were some false negatives, many primers worked for all samples, suggesting that there is little difference in the viral genome across the United States.