Analysis of the metabolic features of plant extremophile species from the Atacama Desert

• Main Author: Dussarrat, Thomas
• Other Authors: Biologie du fruit et pathologie (BFP), Université de Bordeaux (UB)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Université de Bordeaux, Pontificia universidad católica de Chile (Santiago de Chile), Dominique Rolin, Rodrigo A. Gutiérrez, Pierre Pétriacq
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: HAL CCSD 2022
• Subjects: Adaptation; Extreme environments; Multiple species; Predictive metabolomics; Ecology; Plant metabolism; Environnements extrêmes; Multi-Espèces; Métabolomique prédictive; Ecologie; Plante; [SDV.SA]Life Sciences [q-bio]/Agricultural sciences; polar desert
• Online Access: https://theses.hal.science/tel-03923171; https://theses.hal.science/tel-03923171/document; https://theses.hal.science/tel-03923171/file/DUSSARRAT_THOMAS_2022.pdf

Extreme lands lying at the edges of at least one abiotic gradient permit the survival of extremely few species. These so-called extremophile species (literally loving “philos” the extremes) harbour a unique reservoir of genetic and biochemical adaptations that has always attracted human curiosity. Previous studies have shown a high degree of species-specificity for plant adaptation to hostile biomes, thus explaining that successful transfers of protective mechanisms to crops remain scant. However, generic adaptive strategies may also exist. In this context, I propose to carry out a comprehensive approach from the ecosystem to the metabolites to investigate the biochemical adjustments of extremophile plant species from the Atacama Desert, the driest non-polar desert on earth. Plants were collected in their natural environment that spans an elevation gradient from 2500 to 4500m. Multiple metabolomic approaches were combined with machine learning to unveil a generic toolbox for plant resilience to harsh conditions. Subsequently, reaction and pathway enrichment analyses identified genetic legacies underlying convergent biochemical strategies selected through evolution. Finally, the role of positive interactions with the cactus Maihueniopsis camachoi in the adaptation of various plant species to harsh environments was explored. Results yielded a better mechanistic understanding of facilitation processes and the discovery of an intriguing set of metabolites able to predict the interaction status. Overall, while this study provided significant insights into our comprehension of adaptive mechanisms underlying plant resilience to extreme climates, our multi-species approach foreshadows promising studies and discoveries in agronomy and ecology. Les terres extrêmes situées à la limite d'au moins un gradient abiotique permettent la survie de très peu d'espèces. Ces espèces dites extrêmophiles (littéralement, aimant "philos" les extrêmes) abritent un réservoir unique d'adaptations génétiques et biochimiques qui a toujours ...