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Powdery mildews (Erysiphales) in Victorian horticulture: DNA isolation to rediscover an old foe hidden in herbaria

Reannon Smith: DEDJTR, Agriculture Victoria

<div>Powdery mildews pose a significant threat to the global food trade and can cause massive crop losses throughout agricultural and horticultural industries.</p> <p>Maintaining up to date plant pathogen data is vital for Australian Biosecurity. The Victorian Plant Pathology Herbarium (VPRI) houses over 42,000 plant pathogen specimens. Of these the powdery mildews (Erysiphales) represent ~2700 specimens, collected from agricultural, horticultural and ornamental host plants. The VPRI plant pathogen database feeds directly into the Australian Plant Pathogen Database (APPD) providing specimen based records of current plant pathogens. Traditionally, morphology and host plant associations were used for the identification of powdery mildews but this has been proven unreliable. The modern approach to fungal taxonomy is to use morphological characters together with genetic analyses.</p> <p>I will present research on the molecular characterisation of VPRI powdery mildew specimens, focusing specifically on horticultural crops of Victoria, Australia. An integral part of this research is the establishment of reliable DNA extraction methods and identification of appropriate gene regions for species identification of preserved powdery mildews specimens. The aim of this project was to test a range of DNA extraction protocols which used varying source material of different ages (fresh, recent -200 years old and ancient) to compare the DNA quantity and quality yielded from the VPRI powdery mildew specimens. We also evaluated fungal gene markers for use in herbarium fungal species identification.</div>

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