Project Leader

Dr Anne Sawyer, University of Queensland




Myrtle Rust Action Plan Objective 4.3 is to explore methods for resistance and control. In an earlier Foundation project (PBSF034) , we developed RNA interference (RNAi)vaccines that reduced myrtle rust infection on Syzygium jambos. We are on track to complete the project this year, with remaining experiments on RNA uptake/movement in plants and effectiveness of the RNAi vaccines on Decaspermum humile and Syzygium hodgkinsoniae underway. Our next step is to translate these findings to benefit Myrtaceae-based industries and the environment and develop a vaccine registration package with Nufarm. The goal of the proposed project is to prepare RNAi vaccines for in-field applications.

Objectives and Impact

The overall goal of this project, which aligns with Dr Anne Sawyer’s proposed mid-career Advance Queensland Industry Research Fellowship and new partnership with Scion New Zealand, is to prepare RNAi vaccines for field applications through the following aims:
1: Determine the best RNAi vaccine delivery method
2: Determine the longevity of RNAi vaccine-mediated disease protection
3: Test RNAi vaccine efficacy in the field

We will test the ability of different plant tissues (young/old leaves/stems) to take up dsRNA and through RNA extractions and northern blotting examine whether dsRNA moves to distal/newly forming tissue. Longevity of protection will be determined by harvesting tissue at different timepoints (e.g. 1 week, 2 weeks) post dsRNA application. Whole plant bioassays will be performed on Very High priority species (Myrtle Rust Action Plan) Decaspermum humile and Syzygium hodgkinsoniae, and economically and culturally important species Backhousia citriodora and Melaleuca alternifolia to confirm disease protection at the various time points post RNA application in the field. We will work closely with Nufarm to test various formulations for in-field vaccine stability. This project uses new technology to protect iconic Australian Myrtaceae species from myrtle rust, with long-term benefits for Myrtaceae-based industries, conservation and biodiversity.