Mangos are an important industry in northern Australia and affected by mango dieback associated with various members of the Botryosphaeriaceae. The Botryosphaeriaceae family contains about 24 genera and 222 species worldwide, on a diverse range of host plants. These fungi are primary and latent pathogens.
The fungal family: The Botryosphaeriaceae commonly colonise woody host plants as endophytes and express pathogenicity following host stress leading to disease symptoms such as twig, branch and stem cankers, dieback, and fruit rot. Tree symptoms can lead to a loss of productivity and tree death. Changing climatic conditions and horticultural practices such as deficit-irrigation contribute to elevated tree stress leading to increased disease expression from latent infecting pathogens. Understanding the emerging biosecurity risks of latent pathogens threatening tree crop productivity due to changing climate is of vital importance.
Effect on mango: Within this fungal family, the Lasiodiplodia species are of interest because they are commonly associated with mango dieback worldwide. Using a Lasiodiplodia species as a model, this project will explore infection biology and disease expression in mango.
Host-fungus interactions: The host-fungus interactions will be investigated using in-planta experiments and transcriptomics. Gaining an understanding of the infection biology, and how and why Lasiodiplodia switches from an endophytic to pathogenic lifestyle and the factors that contribute to disease expression in mango trees will inform the development of improved disease management strategies.
Aim: The aim of this project is to explore infection biology of Lasiodiplodia species and resulting disease expression in mango.
Meed the PhD student on this project
Vida Burger
I am a PhD student at ANU working on the epidemiological and molecular drivers of mango dieback, in collaboration with the Northern Territory Department of Agriculture and Fisheries. My research focuses on understanding the transition of Lasiodiplodia theobromae from an endophytic to a pathogenic life stage, using in planta experimentation and transcriptomic approaches to investigate host-fungus-environment interactions.
I completed my honours and master’s degrees at the University of Pretoria as part of the Forestry, Agriculture and Biotechnology Institute (FABI), where my research focused on plant virology, including working with apple mosaic virus in hops and pepper ringspot virus in sunflower. This work involved using molecular diagnostics, sequencing, field sampling and glasshouse trials.
My research interests lie in plant pathology and disease epidemiology, with a particular focus on developing a deeper understanding of plant-pathogen interactions and contributing to practical disease management strategies.
Outside of research, I enjoy running, hiking and have recently, taken up AFL training.
Supervisors and advisors
Professor Benjamin Schwessinger and Professor Celeste Linde, The Australian National University.
Stanley Belgrade, Sonu Yadav, and Sharl Mintoff, Northern Territory Department of Agriculture and Fisheries (NT DAF).
Approach
The project will investigate some of the following:
- Infection and colonisation: Glasshouse experiments using mango plants in pots to explore the biology and pathogenicity of Lasiodiplodia species.
Where and how does infection occur, and how extensive is colonisation?
What is required for the endophyte to become pathogenic? What combination of potential plant stressors (eg. wound, water-deficit, plant growth retardant, heat) are required for the endophyte to become pathogenic? - Host – fungus – environment interaction: Using a transcriptomic approach various questions can be asked eg:
a. How does host recognition function for an endophyte?
b. Does plant stress affect host receptor expression, or fungal effector expression, or both? Ie Identify mechanism switch from endophyte to pathogen. - Disease management: Utilising the increased understanding of the mechanics of pathogenicity gained through the previous chapters, explore, design, and field test mango dieback disease management strategies. Are there ways to reduce infection, colonisation, or disease expression?
Questions? Questions about this project can be directed to Sarah Adams, Chief Operating Officer, at plantbiosecurity@anu.edu.au or +61 459 341 281.