Confirmation of Candidature - Candidate : Aftab Ahmad

Powdery mildews are common obligate biotrophic fungal pathogens of plants, including more than 900 species that infect at least 10,000 dicot and monocot plant species globally. From an economic point of view, powdery mildews are one of the most important pathogens of crops that are responsible for significant losses in many agricultural and horticultural industries worldwide. Currently, there are only a few methods to control powdery mildew infections in Australia. These include fungicide applications and using crop varieties that are resistant or tolerant to the disease. Ampelomyces spp. are hyperparasitic fungi that attack powdery mildew colonies and suppress their growth and sporulation in the field. Selected strains were developed as biofungicides overseas, but their efficacy is low. Alternative measures for powdery mildew control are urgently needed. Small RNA (sRNA) molecules have been demonstrated to be efficient in plant disease control. Spraying double-stranded RNA (dsRNA) molecules on infected plants to target essential pathogen genes and downregulate messenger RNA production at the post-transcriptional gene silencing level to protect crops from pathogens is a sustainable and environmentally friendly approach. This approach requires a comprehensive knowledge on the genomics of powdery mildews, the infected crops, and the host-pathogen interactions. The present PhD study will support the efforts towards the development of sRNA-based control of powdery mildews. The first objective is to develop a set of methods that will separate powdery mildew structures from host plant cells and will yield nucleic acid samples that contain DNA or RNA mostly or exclusively from powdery mildews. The second objective is to investigate whether sRNAs from Ampelomyces spp. strains, well-known natural enemies of powdery mildews, have a role in the control of powdery mildews. The third objective is to study the impact of dsRNA that are already known from different plant-pathogen interactions on several powdery mildew species to demonstrate the value of sRNA sprays in controlling powdery mildews on diverse crops.

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