A project undertaken at Western Sydney University, and supervised by A/Prof Michelle Moffitt.
The plant disease ‘Myrtle rust’ arrived in Australia in 2010 and is currently endangering many Australian native plant species belonging to the Myrtaceae family. Plants belonging to the Myrtaceae are one of the major plant families on the Australian continent and consists of Australia’s most iconic native trees, including eucalypts, paperbarks, bottlebrushes and lillypillies among others. There are more than 2000 species of Myrtaceae that have been identified to date with more than one quarter known to be vulnerable to the disease.
Myrtle rust disease causes distinct rust-coloured pustules on leaves, eventually leading to loss of foliage and tree dieback. Flowers and fruits can be infected as well, impacting the ability of the plant to successfully produce seeds. As a result, two species, Rhodamnia rubescens and Rhodomyrtus psidioides have now been listed as critically endangered as a result of Myrtle rust . Studies suggest that many more will be extinct within a generation. The relatively recent incursion of this pathogen into Australia means that little is known about how we may feasibly control it within natural ecosystems. Fungicide sprays can be used in greenhouse settings but have significant detrimental effects in Australia’s forests.
All plants are colonised by a range of microorganisms, including fungi, bacteria and viruses. These communities of microorganisms are thought to play a role in the health of the plant and protection from plant disease, in addition to drought, heat and salinity. The composition and abundance of the microorganisms within this community is vital to protecting the plant. Some of these key microbes may actively produce protective molecules which function to stimulate the plant immune system, regulate the growth of microbes within the leaf community, or may act as natural fungicides. Very little is known about the microbial communities associated with Australian Myrtaceae plants and if they might play a role in protecting plants from Myrtle rust disease.
The aim of this study is to investigate how certain leaf associated fungi isolated from Australian ecosystems, and the natural chemicals they produce, provide a protective role against the plant pathogen, Myrtle rust. Outcomes from these experiments will contribute to the understanding of the breadth of microbes that could control this pervasive disease.
Overall, this project will improve our understanding of the diversity of bioactive metabolites that have evolved in Australian fungi and provide mechanistic evidence for their role and potential application in protecting Australian Myrtaceae from the devastation of Myrtle rust disease.