Research
Broadly, I am interested in: (i) deciphering relationships between root exudates and microorganisms, (ii) manipulating host-microbe interactions to help plants under stress, (iii) the biotic constraints that impact microbial colonisation and functioning on roots and in soils, and (iii) manipulating microbe-microbe interactions and how those interactions impact microbial physiology and responses to the environment. Below are some more specific goals:
Manipulating below-ground feedback
Roots make important relationships with microbes, which are essential for healthy plant functioning and tolerating stress. I examine the microbes that live on the root-surface (rhizoplane) and the root-adjactent (rhizosphere) environments. I examine: (i) how drought-stress impacts plant-microbial relationships and how we can use those microbes to improve plant fitness, and (ii) how does root exudation modulate rhizosphere dynamics. I link root exudation, root physiology, and microbial composition and function, to identify how we can manipulate these relationships, and the ways we can provide beneficial microbes to plants. I am also interested in basic physiology questions, like how do microbes change along a plant root and with branching root order
Manipulating biotic interactions
How do microbial interactions shape microbial establishment and functioning? I use top-down and bottom-up approaches to manipulate microbial diversity in soil to augment or restore soil functions, particularly in agricultural settings where microbial diversity and function is depleted. I use soil mesocosms to identify how soil functions (for example, nitrification) are impacted by diversity loss. I also develop and deploy microbial traps to capture active microorganisms. In soil, the majority of microbes are dormant. I use my microbial traps to see which microbes are available for colonisation (see home page for an image of a microbial trap)
Microbial physiology
How do microbial interactions and abiotic constraints influence the physiology of microbes? I am interested in how microbe-microbe and microbe-host interactions can shift feedback loops in the environment or with a host. For example, do competitive interactions shift towards cooperation in the presence of defence-associated root exudate compounds. Pictured are Paenibacillus cells after introduction to a novel soil environment
Fieldwork
I have extensive experience working in field settings, including in research forests, agroecosystems, and in marine settings. I have worked in numerous research forests to identify: (i) how to microbial composition and function differ with woody root physiology, and (ii) how to soil nutrient amendments impact root exudation and microbial recruitment. In agricultural settings, I examine how microbes intersect with soil health in cover cropping systems, and organically and conventionally managed systems. In a collaboration, I am characterizing root-associated microbes in the amazon rainforest.
Functional assays
I supplement high-throughput sequencing data with functional assays to determine how diversity and biotic constraints impact soil functions and microbial establishment. Pictured is the lab prep for a extracellular enzyme activity assay. I also characterise carbon usage profiles (e.g. ecolog plates) and nitrogen pools to identify how my microbiome manipulations can change the resource usage of the whole community
Molecular techniques
A lot of my earlier training was in molecular biology, where I learnt a number of techniques including cloning (traditional and newer techniques), gene knockouts, using transposons, transformation (chemical, electrical and chitin based), conjugation with auxotrophic strains, antibiotic selection, and working with plasmids. I like to apply my molecular biology thinking and skillset to answer questions in microbial ecology. Pictured is a colony of Vibrio with constitutive green-fluorescent protein expression