Thesis: Eco-physiology of canker-affected Corymbia calophylla (marri): interactive effects of pathogen and abiotic stress factors.
Marri (Corymbia calophylla) is a keystone eucalypt species in Western Australian woodlands and forests, which has increasingly been suffering from stem canker infestations by a pathogenic Quambalaria fungus (Q. coyrecup). The aim of this study is to provide a fundamental understanding of the underlying processes in marri decline using an integrated physiological, biochemical and molecular level analyses. I will conduct several multiple-stress experiments to investigate some key questions related to marri decline: (i) Do abiotic stresses or stress timing influence canker disease progression and plant defense? (ii) Is there a linkage between plant physiological performance, induced defence (chemical and anatomical) and disease severity, (iii) Is there genetic variation amongst marri provenances in disease susceptibility and does susceptibility relate to eco-physiological traits? (iv) How does canker disease affect carbon allocation? I am also interested to investigate relative contributions of hydraulic dysfunction and carbohydrate depletion during canker infected marri tree mortality.
Why my research is important
Currently, the disease is widespread across marri’s distribution range in trees of all age classes, which has major economic, social and ecological implications in the region, including loss of honey production, wildlife habitats, species richness, amenity values and carbon sequestration. The outcomes of this research will provide a fundamental understanding of the interaction between the plant, the pathogen and the environment which is essential to understand epidemiological outcomes. In addition, it will also add new knowledge in plant resistance “systemic induced plant defence in stem” which is remains untested in Eucalyptus spp. pathosystem, which is crucial for developing effective treatments to halt marri decline as well as other declining eucalypts in Australia and around the world.