Research
Broadly, I am interested in: (i) manipulating host-microbe interactions to help plants under stress (e.g. deciphering relationships between root exudation and microbes), (ii) the biotic constraints that impact microbial colonization and functioning in soils (i.e. how can we rescue soil functions), 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 how drought-stress impacts plant-microbial relationships and how we can use those microbes to improve plant fitness. 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 where they "swell"
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