Oral: Viral Diseases
Threat to control Canna Yellow Streak Virus; altered infectivity by associating with a Sub-viral element of novel Canna Yellow Mottle Virus
D. WIJAYASEKARA (1), P. Hoyt (1), B. Dunn (1), A. Gimondo (1), J. Verchot (1) (1) oklahoma state university, U.S.A.
Canna Yellow Mottle Virus (CaYMV) poses a significant threat to the canna industry by causing unwanted virus-like symptoms to the foliage. CaYMV was first reported in 1979 and the full genome has not been reported. In order to determine the full CaYMV genome and characterize the disease, next generation sequencing was carried out using Virion DNA extracted from infected canna plants. The full CaYMV genome consisting of 6976 bp with two associated sub-viral elements (SVE), was recovered. The CaYMV genome and two sub-viral elements were cloned and sequenced using PCR primers. With initial diagnostic experiments using multiplex PCR reported in 2015, CaYMV was found to be associated with Canna Yellow Streak Virus (CaYSV). To determine the nature of this association, analysis of naturally infected canna varieties including greenhouse-grown and field-grown canna for the presence of CaYMV, CaYSV and SVEs was conducted using specific diagnostic primers for CaYMV and SVE 0036. Among six canna varieties, one variety “Australia” tested positive for only the SVE-0036 while another variety “Striped Beauty” tested positive for all three. Sap containing SVE0036, CaYSV, or CaYMV were mixed and used to inoculate bean or lupine plants. Infectivity of CaYSV with the presence of SVE0036 altered in bean and lupine plants. These data suggest that it is important to consider the presence of SVE0036 when testing for CaYSV infectivity.