Miss Rachael Crockett1, Pippa Michael1, Mrs Ashmita Rijal-Lamichhane1, Professor Sarita Bennett1
1Curtin University, Centre for Crop and Disease Management, Bentley, Australia
Biography:
Rachael completed a Bachelor of Agribusiness at Curtin University and has been working as a research assistant with the Centre for Crop and Disease Management for the last 2 ½ years. During this time, she has been involved in projects focussed on the ecology of Sclerotinia and management of Sclerotinia stem rot in canola and lupin crops.
Abstract:
The infection process of the fungal pathogen Sclerotinia sclerotiorum is not well understood in narrowleaf lupins (Lupinus angustifolius) compared with other plant hosts like canola. Our goal was to use confocal microscopy to gain better insight into early infection by S. sclerotiorum and subsequent Sclerotinia stem rot disease progression in lupins.
Confocal microscopy is widely used to study plant-fungal interactions. The method typically involves fluorescent tagging of the fungal pathogen through genetic transformation to identify and contrast the pathogen from its host. However, a fitness penalty is often introduced through the transformation process. Specialised laboratory quarantine arrangements are also required reducing the inoculation methods that can be used.
A new method developed by North Dakota State University which stains fungal chitin with a fluorescein labelled protein, still enables high resolution, three-dimensional images for detailed investigation of pathogen infection methods and host response within layers of plant tissue. This makes it possible to image any isolate of S. sclerotiorum without genetic transformation and associated loss of virulence. Adapting this method has allowed us to visualise natural Sclerotinia-lupin infection interactions from wildtype ascospore assays on leaves, stem and pods which would not have been possible using traditional methods.
Early findings show the method works well for staining a variety of lupin tissues and shows initial infection process by S. sclerotiorum before visible lesions are present. It provides an opportunity for better understanding the mechanisms behind Sclerotinia pathogenicity and lupin response. With additional processing of confocal images, resistance phenotyping and fungicide efficacy can also be investigated.