Poster Presentation Science Protecting Plant Health 2017

Ipomoea setosa; and effective and reliable tool for the detection of SPLCV in sweetpotato (#215)

Sandra E Dennien 1 , Michael J Hughes 2 , Eric A Coleman 3 , Amit C Sukal 4 , Craig W Henderson 5 , Rachael J Langenbaker 6 , Denis M Persley 7 , Victor J Galea 8
  1. Agri-science QLD, Department of Agriculture and Fisheries QLD, Gatton, QLD, Australia
  2. Agri-science QLD, Department of Agriculture and Fisheries QLD, Mareeba, QLD, Australia
  3. R&D committee, Australian Sweetpotato Growers Association, Gracemere, QLD, Australia
  4. Centre for Tropical Crops and Biocommodities, Queensland University of Technology , Brisbane, QLD, Australia
  5. Henderson RDE, Bright, Victoria
  6. Agri-science QLD, Department of Agriculture and Fisheries QLD, Bundaberg, QLD, Australia
  7. Agri-science QLD, Department of Agriculture and Fisheries QLD, Ecosciences precinct, QLD, Australia
  8. The University of Queensland, Gatton, QLD, Australia

The Australian sweetpotato industry has undergone remarkable growth and massive productivity improvement in the last 16 years. It is now the most intensive commercial sweetpotato production system in the world, with growers attaining the highest commercial yields per hectare. Much of this is due to the development of a pathogen tested (PT) clean seed scheme from the early 2000s, providing Australian growers with significantly improved quality planting material. Growers currently market over 90,000 tonne per annum of fresh sweetpotatoes worth over $100 million. A key facet of the Australian sweetpotato PT program at the Department of Agriculture and Fisheries Queensland’s Gatton Research Facility has been the use of herbaceous indicator plants such as Ipomoea setosa to screen for viral pathogens. Critical knowledge for the PT process is an understanding of endemic viruses of concern to the industry and an awareness of any potential biosecurity threats. While I. setosa is regarded as a reliable method to detect virus presence in sweetpotato globally it is widely considered to be non-specific for many viruses. Between 2006 and 2016, as part of routine germplasm screening, unusual symptoms such as leaf cupping, stunting and chlorosis were observed on grafted I. setosa plants. Sweetpotato plants used as scions were observed to be largely asymptomatic over this 10 year period. NCM-ELISA testing produced negative results. PCR testing with degenerate geminivirus primers in 2006 and Sweetpotato leaf curl virus (SPLCV) specific qPCR testing, 2014 to the present has consistently produced positive SPLCV detections in I. setosa plants exhibiting these specific symptoms. Sequence information correlates the observed symptoms on I. setosa plants to SPLCV infection. Australian results suggest that the particular symptoms observed on I. setosa are associated with SPLCV infection, and that experienced operators can deduce the presence of SPLCV in sweetpotato by observing grafted .setosa plants.