The forgotten diversity: role of population genetic diversity in division of labour and population growth in bacteria

Healthy plant microbiota includes not only mutualists but also a number of commensals with pathogenic potential and these microbes may become pathogenic at high abundance. Thus, understanding whether and how individual microbial species succeed in root colonization and can establish durably in the root microbiota has potential for the development of microbiota-assisted sustainable agriculture practices. Recent advances show that robust root colonizers like deploy multiple independent strategies that co-function to promote colonisation and persistence at roots (Getzke et al., 2023). Other recent reports (Mataigne et al. 2021, Mataigne et al. 2022), indicate that metabolic interdependencies and cross feeding exchanges are widespread among taxonomically diverse bacteria and likely drive microbial co-existence within complex bacterial communities. The major goal of the project is to obtain mechanistic insights into whether and how a robust bacterial root coloniser can partition tasks (division of labour) to achieve greater functional diversity, minimise the energetic cost of processes, and adapt to environmental constraints. More precisely, the project will investigate the importance of population diversity for population growth under nutrient constraint using a library of Pseudomonas brassicacearum R401 mutants and a high throughput automated millifluidic system.

The student will be involved in microbiological work (bacterial cultures, assembly of bacterial communities), millifluidic experiments in fully controlled conditions and the analysis of bacterial growth data generated. The student will also be involved in other experiments part of the DiviDE project.

The student will gain skills in microbiology (microbial cultures, inoculations), in-vitro experimentations including a millifluidic system (Millidrop AzurEvo) and statistical analyzes in R.

The internship is integrated into the DiviDE “Division of labour among genetically Identical ;bacterial intra-populations as an organizational rule Driving root microbiota Establishment” project involving INRAE IGEPP, the UMR Ecobio (University of Rennes 1) and the Max Planck institute for plant Breeding Research (Cologne, Germany).