Skip to Main content Skip to Navigation
New interface
Preprints, Working Papers, ... (Preprint)

A selective bottleneck during host entry drives the evolution of new legume symbionts

Abstract : During the emergence of new host-microbe symbioses, multiple selective pressures-acting at the different steps of the microbial life cycle–shape the phenotypic traits that jointly determine microbial fitness. However, the relative contribution of these different selective pressures to the adaptive trajectories of microbial symbionts are still poorly known. Here we characterized the dynamics of phenotypic adaptation and its underlying genetic bases during the experimental evolution of a plant pathogenic bacterium into a legume symbiont. We observed that fast adaptation was predominantly driven by selection acting on competitiveness for host entry, which outweighed selection acting on within-host proliferation. Whole-population sequencing of evolved bacteria revealed that phenotypic adaptation was supported by the continuous accumulation of new mutations and the sequential sweeps of cohorts of mutations with similar temporal trajectories. The identification of adaptive mutations within the fixed mutational cohorts showed that all of them improved competitiveness for host entry, while only a subset of those also improved within host proliferation. Computer simulations predict that this effect emerges from the presence of a strong selective bottleneck at host entry. Together, these results show how selective bottlenecks can alter the relative influence of selective pressures acting during bacterial adaptation to multistep infection processes.
Document type :
Preprints, Working Papers, ... (Preprint)
Complete list of metadata

https://hal-cnrs.archives-ouvertes.fr/hal-03811656
Contributor : Delphine CAPELA Connect in order to contact the contributor
Submitted on : Wednesday, October 12, 2022 - 9:30:32 AM
Last modification on : Friday, December 2, 2022 - 4:49:38 PM

Licence


Distributed under a Creative Commons Attribution - NonCommercial 4.0 International License

Links full text

Identifiers

Citation

Ginaini Grazielli Doin de Moura, Saida Mouffok, Nil Gaudu, Anne-Claire Cazalé, Marine Milhes, et al.. A selective bottleneck during host entry drives the evolution of new legume symbionts. 2022. ⟨hal-03811656⟩

Share

Metrics

Record views

0