Sniffing out citrus canker and beyond

The Northern Territory’s citrus industry came under attack in 2018 from a highly contagious bacterial disease called citrus canker. Citrus canker is a highly infectious bacterial disease caused by the bacterium Xanthomonas citri subsp. citri (Xcc). Severe infection can lead to defoliation, dieback, blemished fruit, and premature fruit drop.

CDU chemists, Dr Hao Wang and Dr Vinuthaa Murthy won a contract with the Department of Industry, Tourism and Trade (DITT) in 2020 to develop a scent profile and synthesise artificial scent lures for the detection of citrus canker disease.

The project set out to determine the volatile organic compound (VOC) profile of the infected citrus plants at the CDU, Yellow 2 labs using the gas chromatography-mass spectrometer (GC/MS). Key chemical compounds emitted by different citrus varieties, both infected and non-infected, were identified over time. Artificial scent blends (lures) were synthesised based on the VOC profile and provided to DITT. Two sniffer dogs are now trained with the artificial lure to detect the citrus canker-infected plants.

This presentation will also provide an overview of the analytical chemistry instrumentation available at CDU, Yellow 2 labs for identifying and quantifying the chemical components of natural and synthetic materials.

Dr Vinuthaa Murthy is a Senior lecturer in Chemistry at the College of Engineering, IT & Environment and the current president of the Royal Australian Chemical Institute, NT branch. Her expertise is on applying Computational and Analytical Chemistry techniques to solve the structural properties of small molecule interaction with macromolecule surfaces. Currently her research focuses on characterisation of nanoparticles conjugated with native plant extracts with biomedical applications such as antimicrobial and wound healing and nano-systems used in water treatment to remove persistent contaminants.

Dr Hao Wang is a Senior Technical Officer managing the newly established analytical chemistry laboratory at Energy and Resources Institute, CEITE. Before joining CDU, He worked in the Global and Tropical Health Division of Menzies School of Health Research, studying malaria treatment and drug resistance. His expertise is in analysing small molecules using instrument with various chromatography and spectrometry techniques.