Mechanisms and manipulation of resistance to powdery scab in potato roots (PT17003)
What’s it all about?
While the potato tuber blemishes that are caused by powdery scab are a concern for the potato industry, the pathogen’s effect on plant roots can’t be underestimated, either. Root infection with powdery scab disrupts root function – meaning more irrigation, fertiliser and fungicides are needed to compensate for poor root development – and leads to diminishing yields.
In this project, researchers are investigating root resistance to powdery scab infection. This involves looking at how the pathogen infects roots and causes disease, what allows for resistance in some potato varieties, and whether resistance mechanisms may be boosted or transferred.
While caused by the same pathogen, the powdery scab root and tuber infection processes are separate, and different plant resistance processes operate against each. This means that varieties that show resistance to tuber disease don’t necessarily show resistance to root infection. However, when root infection is decreased, disease across the whole plant is slowed, meaning tuber disease is reduced as well.
Preliminary studies have shown that reduced root binding by zoospores is correlated with reduced disease and yield loss and that potato cultivars vary, with some showing reduced binding and subsequent infection. However, virtually nothing is known about the nature of the root binding sites and the basis of this resistance.
To date, the project team have progressed the following research activities:
- The root surface protein study and variant resistance screening has commenced, with the preferential binding sites across susceptible and resistant cultivars being determined which provides a target region for examination of root surface proteins.
- Screening of the test cultivars has been conducted to ascertain efficiency of differentiation of susceptible and resistant cultivars. Screening of the large variety collection has commenced and will take two to three months to complete.
- Project team members attended an international symposium on Spongospora disease research in September 2019 to present information about the project and hold collaborative technical discussions aimed at progressing project outcomes.
- Aspects of the project were presented to an audience of 113 industry members at the Forthside Tasmanian Institute of Agriculture Vegetable Facility Open Day held in December 2019.
Next steps for the project team are to:
- Determine the nature of spore root attachment
- Characterise cultivars for this important type of resistance
- Examine the capability of manipulation of attachment sites through binding blockers or similar approaches
- Develop and screen variants of important commercial cultivars that have altered root attachment capacity, and analyse these for genetic changes associated with reduced binding that will be useful for rapid screening of new germplasm.