Transformational crop protection – Innovative RNAi biopesticides for management of sugarcane root feeding pests

Current crop protection strategies rely on plant genetic resistance and pesticide sprays. Toxicity both in terms of human health and the environment, lack of specificity, and the development of resistance, persistence of residues and runoff into our precious waterways are major issues with the use of chemical pesticides.

Transformative RNA based biopesticides or ‘RNA vaccines’ for plants as sustainable biological crop protection platform without the need for generic modification is gaining momentum across the globe. This involves topical application of pest specific double stranded RNA (dsRNA) as the key trigger molecule of RNA interference. On its own RNA is inherently unstable, and therefore requires optimisation to improve its performance for industry relevant applications.

The University of Queensland has developed a transformational platform of using clay particles as carriers of pest/pathogen targeting RNA which provides stability, rain-fastness, and slow and sustained release of the biological active or dsRNA to afford an extended window of protection.

Greyback canegrub is a major pest throughout Australian sugarcane growing regions and a significant constraint for about 50% of growers. Existing control measures for cane grubs are limited to imidacloprid use and there is no insecticide registered for soldier fly. The current project aims to deliver proof-of-concept for delivering RNA biopesticides as an innovative non-GM, non-toxic, ecologically safe topical application for the control of canegrubs as serious pests of sugarcane. It will involve identification of the best target genes for RNA based biopesticides for both canegrubs and soldier fly and testing the RNAi based pesticides in feeding assays/glasshouse against canegrubs.

• To sequence and annotate the transcriptomes of greyback canegrub and soldier fly
• To investigate the movement and uptake of the biological active (dsRNA) in sugarcane to define practical delivery options and feaseability of the approach
• To design dsRNA constructs targeting critical genes of the canegrub and soldier fly using specifically developed software packages
• To screen the constructs designed for canegrub as a first case study in feeding assays
• To load the selected constructs on either BioClay/BenPol delivery platform to proof efficiency in artificial feeding assays before moving to phase 2