RA6 THESIS: Characterising Effector Protein AP1260

Characterising Effector Protein, AP1260, of the Myrtle Rust Causing Austropuccinia psidii

2022

Sullivan J. 2022. Characterising Effector Protein, AP1260, of the Myrtle Rust Causing Austropuccinia psidii. Unpublished BSc honours thesis, University of Canterbury. 54 p.

ABSTRACT

Significance

Myrtle rust is caused by the invasive fungus Austropuccinia psidii and is incredibly infectious and physically devastating to Myrtaceae plants. The pandemic biotype of the disease has spread across five continents and was first detected in New Zealand in 2017. The presence of the disease in Australia has already caused major declines in Myrtaceae populations (e.g., eucalyptus) and now threatens New Zealand natives, including taonga species such as pōhutukawa, mānuka and rātā.

Rationale

Transcriptomics by collaborators at Plant and Food Research identified several proteins that are expressed in the early stages of A. psidii infection of mānuka—a signature that they are important for the infection of plant cells. In other fungi, these ‘effector proteins’ are known to manipulate the host plants cellular processes. My research focuses on one of these effector proteins, AP1260. The aim is to define the characteristics of AP1260 through bioinformatic and biophysical analysis.

Results

The results obtained in this study represent the first studies of an A. psidii effector protein. Characteristics such as mass, dynamics, stability, and shape of AP1260 were determined. This led to the discovery of a potentially intrinsically disordered region within AP1260.

Conclusions

Characterisation of AP1260 will vastly improve the knowledge of the mechanisms of A. psidii infection and may uncover methods to interfere with its function, making its characterisation critical to the biosecurity of nations with Myrtaceae populations. The outcome of this research will be critical for developing methods for controlling and potentially preventing myrtle rust disease.