Fungal diseases cause major reductions on crop productivity
Crops are impacted by fungal diseases that can cause complete yield losses in the worst-case scenario. The two most common options farmers have for reducing the impact of these diseases are via the use of fungicides or by harnessing the plant's own immune system. Using the plant immune system or "resistance genes" is much preferred over fungicides as a more cost effective and environmentally friendly method to control disease.
The target crops of this work, sorghum and rice, are important crops in sub-Saharan Africa and Asia respectively and both are impacted by devastating fungal diseases such as sorghum anthracnose and rice blast. It is critical that new varieties with durable resistance are developed since resistance genes can be overcome rapidly by fungal pathogens. Additionally, farmers and growers often cannot afford chemical treatments in order to protect their crops.
Developing a better understanding of broad-spectrum resistance
A naturally occurring resistance gene from wheat, referred to as Lr67, was previously identified by the team at CSIRO. This gene confers durable, partial resistance against multiple fungal pathogens that cause rust diseases and powdery mildew in wheat. The Lr67 gene belongs to the STP13 family of sugar transporters and is highly conserved in all plant species. However, orthologous resistance causing variants of Lr67 in rice and sorghum have not been detected by screening geographically diverse populations. The mechanism by which this gene confers disease resistance is not fully understood but efforts are being made to improve knowledge in this area.
Producing broad-spectrum disease resistant crops
We have developed a better understanding of the molecular function of the Lr67 gene, which has in turn informed our strategy for designing and producing disease resistant crops. Armed with this information, together with our project collaborators at the Biosciences eastern and central Africa-International Livestock Research Institute (BecA-ILRI) Hub and the International Rice Research Institute (IRRI; Philippines), sorghum and rice lines are currently being generated in the project, which will be tested for resistance against sorghum anthracnose and rice blast diseases.