PhD defence - Courtney H. Herms
Decoding the impact of root morphological traits on microbial colonization and activity in the wheat rhizosphere at single-strain and whole-community levels.
Assessment Committee
Ass. Professor Kristian Koefoed Brandt (Chair), PLEN, University of Copenhagen, Denmark
Principal Research Scientist Tim Mauchline, Sustainable Soil and Crops, Rothamsted Research, UK
Professor Ákos Kovács, Leiden University, Belgium
Supervisors
Ass. Professor Mette Haubjerg Nicolaisen, PLEN, University of Copenhagen, Denmark
Ass. Professor Rosanna C Hennessy, PLEN, University of Copenhagen, Denmark
Place
Copenhagen Plant Science Centre, Aud. A2 – 11.01, Thorvaldsensvej 40, 1871 Frederiksberg
The defence is followed by a reception in meeting room B212 on 2nd floor
Ask for a copy of the thesis: meni@plen.ku.dk
Summary
Plant roots orchestrate a complex and vibrant soil habitat known as the rhizosphere. Microbial communities in the rhizosphere are well known for their critical role in plant health and development and are thus emerging as key players in reducing the climate footprint of agriculture. However, the utilization of these microbial communities for sustainable agriculture depends on our ability to understand how the plant influences community assembly and function.
In this thesis, I focus on how wheat root morphology, namely root diameter and root hairs, drives microbial composition and functional abilities. Using combinations of culture-dependent and culture-independent methods, I identify communities associated with cultivars of different root thickness, and in an opinion piece, highlight the importance root diameter in generating a unique physical and chemical landscape for microbial colonization. In parallel, I explore the dynamics of intragenus microdiveristy of Pseudomonas, a key member of rhizosphere microbiomes known for their diverse metabolic capabilities. Using a wheat mutant line defective in root hair elongation, I reveal interactions between phosphorus-cycling and phytohormone-producing microbes and the plant that driven by root hairs.
Taken together, this thesis highlights root morphology as a key factor influencing rhizosphere microbiome assembly. By linking root traits to microbiome assembly and function, this work supports targeting root phenotypes in breeding strategies to promote microbe-mediated sustainable wheat cultivation.