HOUSE - The plant-microbiota holobiont in the rhizosphere: a selection unit?

Context and challenges

In plants, the rhizospheric microbiota is involved in many exchanges of nutrients, exudates, water, signal molecules with the plant, with major consequences for plant nutrition, immunity and development. The fidelity of association between the plant and this microbiota could be due to vertical transmission via seeds or the production of vegetative organs in clonal species. But in the end, none of these elements demonstrate that the holobiont is a real unit of selection from which adaptations emerge, as the host may simply be a habitat that systematically suits the same microbial species.

Goals

The objective is to show whether or not the plant holobiont is a unit of selection, with vertical (inter-generational) transmission of variability in microbiota composition in interaction with the host.

The microbiotas of the rhizosphere and seeds will be monitored over eight generations in a plant species with a short lifecycle, Brassica rapa. The results will make it possible to determine whether:

1. Rhizosphere plant-microbiota interactions could be selected,  and thus whether the holobiont constitutes a selection unit;
2. The microbiotas of the rhizosphere and seeds remain stable over generations;
3. The transmission of micro-organisms via seeds influences the rhizosphere microbiota.

The partners will pool their expertise on the microbiota of the rhizosphere and of seeds as well as their knowledge in evolutionary science and artificial selection and the cross-generational transmission of micro-organisms

The results will enable identification of the best strategy for plant breeding programmes that take account of the microbiota.

INRAE partners