Poster Presentation Australasian Plant Pathology Society Conference 2025

RNA biopesticides for next generation protection of crops and native plants (#140)

Rebecca Degnan 1 , Leny Jane Pame 1 , Sebastian Orellana-Quinteros 1 , Luciasih Agustini 2 , Ken Pegg 3 , Donald Gardiner 4 , Alistair McTaggart 4 , Louise Shuey 3 , Bernard Carroll 1 , Neena Mitter 4 5 , Anne Sawyer 1 4
  1. School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, QLD, Australia
  2. School of Agriculture and Food Sustainability, The University of Queensland, St Lucia, QLD, Australia
  3. Queensland Department of Primary Industries, Dutton Park, QLD, Australia
  4. Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, St Lucia, QLD, Australia
  5. Charles Sturt University, Wagga Wagga, NSW, Australia

Invasive plant pathogens threaten global food security and biodiversity, causing significant yield losses in calorie crops and epidemics in natural ecosystems leading to population decline and extinctions. Disease management relies heavily on chemical pesticides, however, these are expensive, slow to develop, harmful to humans and the environment, and have low public acceptance. New crop protection strategies that are effective but environmentally, culturally and economically responsible are urgently needed. RNA biopesticides have emerged as a game-changing crop protection platform that is pathogen-specific, does not require any modification to the plant, or leave harmful residues in the environment. The approach involves spray application of pathogen-specific double-stranded RNA (dsRNA) to host plants to trigger RNA interference (RNAi) in the invading pathogen. This leads to silencing of essential pathogen genes, inactivating the pathogen and preventing infection1. Over the last seven years we have been developing RNA biopesticides against fungal and oomycete pathogens of crops and native plants. We demonstrated for the first time that exogenous dsRNA targeting conserved fungal genes is highly effective as a preventative and curative treatment for myrtle rust2,3, caused by Austropuccinia psidii, and have shown that this approach shows great promise for controlling Botrytis grey mould4 and Phytophthora root rot. The bottleneck to translation is knowledge of dsRNA spray rate, frequency and efficacy in the field. We are now addressing these questions and investigating the mechanisms of RNA biopesticide-mediated disease control, including understanding why RNA biopesticides are more effective against some pathogens than others. The results will answer questions about systemic protection, effectiveness against foliar versus root pathogens, functionality in different host plants/pathosystems and synergistic effects with existing controls. This will inform research on other pathogens, including biosecurity threats, and guide a future of innovative next generation crop protection leading to healthier terrestrial and aquatic ecosystems.

(1) Mann CWG, Sawyer A, Gardiner DM, Mitter N, Carroll BJ, Eamens AL (2023) RNA-based control of fungal pathogens in plants. International Journal of Molecular Sciences. 24:12391.

(2) Degnan RM, McTaggart AR, Shuey LS, Pame LJS, Smith GR, Gardiner DM, Nock V, Soffe R, Sale S, Garrill A, Carroll BJ, Mitter N and Sawyer A (2022) Exogenous double-stranded RNA inhibits the infection physiology of rust fungi to reduce symptoms in planta. Molecular Plant Pathology, 24(3):191-207.

(3) Degnan RM, Shuey LS, Radford-Smith J, Gardiner DM, Carroll BJ, Mitter N, McTaggart AR, Sawyer A (2023) Solutions for a plant disease epidemic: double-stranded RNA prevents and cures infection by rust fungi. Communications Biology, 6(1) https://doi.org/10.1038/s42003-023-05618-z

(4) Niño-Sánchez J, Sambasivam PT, Sawyer A, Hamby R, Chen A, Czislowski E, Li P, Manzie N, Gardiner DM, Ford R, Xu ZP, Mitter N, Jin H (2022) BioClay™ prolongs RNA interference-mediated crop protection against Botrytis cinerea. Journal of Integrative Plant Biology. 64(11):2187-2198.

  • I would like to participate in the poster speed presentation: No