Poster Presentation Science Protecting Plant Health 2017

Alternate Ipomoea species as a diagnostic tool for enhancing virus detection in sweetpotato (#213)

Emma A Coleman 1 , Sandra E Dennien 2 , Jean Bobby 2 , Victor J Galea 1 , Craig WL Henderson 3
  1. The University of Queensland, Gatton, QLD, Australia
  2. Department of Agriculture and Fisheries, Gatton, QLD, Australia
  3. Henderson RDE, Bright, VIC, Australia

Research into yield decline in sweetpotato has confirmed virus infection as the most limiting factor impacting worldwide production. To improve Australian sweetpotato commercial yields, Australian researchers developed a pathogen tested seed scheme consistently providing growers with first generation, clean planting material. Production of sweetpotato in Australia has since increased by around 1700%, and the regular provision of clean planting material is a now a commercial operation. Virus-infected sweetpotato plants are often asymptomatic, hindering visual virus detection. Sweetpotato sap contains inhibitors which can interfere with detection using standard virus diagnostic methods. The Australian sweetpotato pathogen testing process uses a range of complimentary diagnostic procedures to overcome these issues, the most important being the use of Ipomoea setosa as an herbaceous indicator plant. I. setosa is highly susceptible to infection by sweetpotato viruses, and though the grafting and symptom observation process is time consuming, it enables rapid increase in virus titres, enhancing the accuracy of both NCM-ELISA and PCR. The susceptibility of Ipomoea species to sweetpotato infecting viruses is relatively unexplored. This study aims to investigate the development and expression of common sweetpotato viruses in a range of Ipomoea species, using graft inoculation with known negative and positive control plants. This will provide information on the suitability of alternate Ipomoea species as indicator plants. The inclusion of native Australian Ipomoea species in this investigation will provide additional information on possible biosecurity concerns should virus incursions occur. Species assessment criteria includes virus susceptibility, timing of symptom expression, severity of symptoms, suitability for grafting, available leaf observation area and the effectiveness of NCM-ELISA and PCR detection using index plant tissue. Initial findings from this study indicate that several alternate Ipomoea species are susceptible to common sweetpotato viruses and may exhibit symptoms earlier than I. setosa enabling more rapid detection in an extended annual detection window.