Dr Treena Burgess

Room: BioSc/3.039

Research

I am particularly interested in tree diseases, especially those that are emerging in new environments when tree species are planted as exotics. My main focus is on eucalypts in Australia and in exotic plantations worldwide. A number of new diseases are emerging on these exotic plantations and they potentially threaten the Biosecurity of Australian native forests and eucalypt plantations. My interest is in the worldwide movement of forest pathogens. The population genetics of different pathogens are studied using molecular markers to assess gene and genotypic diversity, gene flow, mode of reproduction, origin of species and cryptic speciation. I am also interested in molecular phylogenetics and matching classical taxonomic traits to molecular phylogenetic traits. This overall outcome encompasses issues of risk assessment and importation and quarantine issues. We have just received funding for an ARC discovery project entitled "Population genetics of fungal pathogens that threaten the biosecurity of Australia's eucalypts". This project will commence in 2003 and there will be many interesting population genetics projects in this area.

Projects

Investigation of Botryosphaeria spp. associated with Proteas in Western Australia

In Western Australia there is a successful cut flower industry using Proteas and related species introduced to Western Australia from South Africa. In South Africa, in the native environment, proteas are very susceptible to diseases caused by Botryosphaeria spp. However, they are also susceptible to Botryosphaeria spp. associated with native Western Australian flora. This project would involve collecting Botryosphaeria spp. from Proteas and nearby nativevegetation in Western Australia. Isolates would be identified using molecular phylogenetics and molecular markers would be used to assess the gene flow between native vegetation and protea plantations.

Population genetics of Botryosphaeria spp. associated with eucalypt plantations in Western Australia

Botryosphaeria spp. are among the most common and devastating pathogens of eucalypt plantations. However, disease caused by Botryosphaeria spp. is rare in Western Australian blue gum plantations. Initial investigations have revealed two new species of Botryosphaeria in Western Australia, and the apparent absence of more damaging species. This needs to be investigated further and this project would involve further surveys, pathogenicity trials and population analysis.

Apart from the projects outlined, there are numerous other potential projects arising as we conduct field trips in Queensland and Asia. In addition we have a number of potential projects in Association with the Forestry and Agriculture Biotechnology Institute (FABI) in South Africa.

Movement of introduced eucalypt pathogens into native forests in Western Australia

Over the past 20 years, the area of eucalypt plantations in Western Australia has increased dramatically. Today there are over 300 000 ha, predominantly of Eucalyptus globulus. This eucalypt species is not native to Western Australia and since its introduction a number of leaf pathogens, not previously known to the region, have been identified. It is hypothesized that these pathogens may have been introduced on E. globules germplasm. This project would involve surveys of E. globules plantations and adjacent native forests, identification of pathogens (classic and molecular), pathogenicity trials and where available the examination of gene flow between the plantations and native forests using molecular markers.

Pathogens of native eucalypts in Northern Australia

Over 3 billion ha of eucalypts are planted outside Australia predominantly in tropical and sub-tropical regions. Many diseases have emerged on these plantations that are not present in Australia. The potential impact of the introduction of these diseases to Australia’s native eucalypts is not known. However, there are some diseases of particular concern namely the ’eucalypt rust’ and the leaf blight caused by Phaeophleospora destructans. The most likely point of entry of these pathogens and the greatest impact would be northern tropical Australia. Very little is known about diseases already present in the north. This project would involve conducting surveys of disease in native forests and taxa trials in the Northern Territory and the molecular and classical identification of the pathogens.

Movement of native eucalypt pathogen Phaeophleospora eppicocoides from native forests into plantations

One of the biggest constraints to eucalypt plantations in Australia is the proximity of native forests and the movement of diseases from the native forests into the plantations. The impact of these diseases is much greater in the plantations that in the forests. It is assumed that this is because of the plantations being an even aged monoculture, but it could also be due to the selective movement and subsequent success of more virulent genotypes of the pathogen. This project would involve the collection of populations of Phaeophleospora eppicocoides in native forests and adjacent eucalypt plantations the determination of diversity and gene flow using molecular markers.

Population biology of eucalypt weevil in Western Australia

The eucalypt weevil (Gonipterus spp.) is responsible for the majority of leaf and shoot damage in 3-4 year old bluegum plantations in Western Australia.  There is a routine survey every spring in susceptible plantations to monitor egg numbers and at a threshold level these plantation will be sprayed to control the damage caused by the feeding larvae.  The weevil has been spread to most eucalypt growing regions of the world, but numbers are generally kept low by the use of a parasitic wasp for biological control.  Attempts to establish the parasitic wasp as a control in western Australia has failed.  The aim of this project would be to use molecular markers to determine the diversity and the origin of the eucalypt weevil in Western Australia.

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