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Thomas DUSSARRAT

Team Metabolism (META)

Spécialité du doctorat : Biologie Végétale

Wednesday, April 20, 2022 - 3:00 p.m. - Amphithéâtre Colette & Josy Bové - Campus INRAE Villenave d'Ornon

Abstract :

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.

Jury :

• M. Michel HERNOULD
  Professeur des universités Université de Bordeaux - INRAE UMR BFP - Examinateur
• M.  Cédric BERTRAND
  Professeur des universités Université de Perpignan - Rapporteur
• Mrs Anne-Emmanuelle HAY DE BETTIGNIES
  Maîtresse de conférences Université de Lyon Rapporteur
• M. José O'BRIEN
  Maître de conférences Pontificia Universidad Católica de Chile - Examinateur
• M. Dominique ROLIN
  Professeur Université de Bordeaux - UMR INRAE BFP - Directeur de Thèse
• M. Rodrigo GUTIERREZ
  Professeur - Co-Directeur de Thèse
• M.Pierre PETRIACQ
  Université de bordeaux, UMR INRAE BFP - Co-Directeur de Thèse