Discovering rust effectors

The challenge

Developing durable resistance to rust pathogens

Rust pathogens secrete an arsenal of proteins, termed effectors, that manipulate their host's physiology and promote disease. Globally, rust pathogens lead to annual crop losses of $1 billion. Plants can detect effectors using their immunity receptors, and this detection leads to the activation of defence pathways, resulting in resistance to the invading pathogen.

However, effectors can evolve to escape being recognised by the plant, leading to disease. To combat rust disease and develop new, durable disease resistance in crops we need a better molecular understanding of effector function and disease resistance in the host plants.

Our response

Paving the way for the identification of effectors from rust fungi

Our research using the model flax – flax rust pathosystem – has led to the identification of multiple effector proteins. This has provided insights and understanding of their functions, and how they are being recognised by their corresponding immunity receptors. In other cereal rust pathogens only a limited number of effector proteins have been identified to date, limiting our understanding of rust pathogenesis. We are developing resources and tools to identify and validate effectors from cereal rust pathogen to inform the development and deployment of durable resistance.

The results

Toward durable disease resistance using engineering approaches

Our research findings and publications are providing significant advancements in our understanding of the interactions between plants and their invading rust pathogens. We have pioneered the discovery of effectors from flax rust and wheat stem rust and are expanding our research into other cereal rust pathogens.

To date, we can monitor natural variants of the effectors, AvrSr50 and AvrSr27 from wheat stem rust populations in the field. This allows us to better understand how these proteins are evolving, which is essential to predict when resistance may breakdown and inform future breeding efforts. We are continuing to identify rust effector proteins and understand how they are recognised by their hosts to develop durable disease resistance and move toward engineering synthetic disease resistance in important crop species, such as wheat.