Description du projet
La résistance des algues face au stress peut s’avérer être la clé pour leur survie
Les plantes terrestres, tout comme les animaux terrestres, peuvent retrouver la trace de leurs ancêtres jusque dans les océans. Néanmoins, les plantes terrestres descendaient toutes d’un seul ancêtre, une algue streptophyte. Nous ignorons encore ce qui a favorisé ces algues particulières dans leur dernière quête réussie vers la conquête des terres. Des scientifiques ont récemment identifié la lignée contemporaine des algues streptophytes plus étroitement liée à l’ancêtre algal des plantes terrestres. TerreStriAL, en s’appuyant sur les données antérieures des chercheurs indiquant que ces algues possèdent des gènes d’une hormone de réponse au stress des plantes terrestres, se dirige vers le Saint Graal. Les modèles algaux permettront aux scientifiques d’étudier les voies de stress chez les algues. Le fait de raccorder ces processus à des modèles in silico aidera les chercheurs à accélérer le processus évolutif et à voir si les algues deviennent des plantes terrestres.
Objectif
Land plants abound on Earth’s surface. All of this diversity arose in a singular event. The algal progenitor of land plants was a streptophyte alga and only recent phylogenomic analyses have specified the particular algal lineage that is most closely related to land plants. But why did land plants evolve only once? And what properties did the ancestors of these terrestrial organisms possess that allowed them to conquer land? Life on land involves rapid and drastic shifts in temperature, light or water availability. Hence, a prime candidate property is the ability to deal with these terrestrial stressors by dynamically responding to shifting environmental cues. My recent data highlight that the streptophyte algae closest to land plants have the genetic makeup for land plant-like stress response signalling circuits—including genes for sensing the major stress phytohormone abscisic acid (ABA). This provides us with testable candidates. To shed light on the early evolution of one of land plants’ key properties, I, here, propose to combine in-depth molecular biological analyses of these candidate stress signalling and response pathways with large-scale systems biology approaches. For this, my team and I will develop streptophyte algal model systems. We will dissect the regulatory hierarchy employed during stress signalling and the response pathways it is regulating in real-time in vivo and across evolutionary time in silico. These approaches will go beyond a view of gene evolution that is based on presence/absence to address if land plant stress dynamics have evolved from algal stress regulatory networks that became hardwired into land plant biology. The aim of this work is to infer the biology of the earliest land plants by investigating their closest algal relatives and interrogating a candidate mechanism used to deal with the challenges of life on land. Understanding this mechanism means understanding a key player that paved the way for the success of plants on land.
Champ scientifique
Programme(s)
Thème(s)
Régime de financement
ERC-STG - Starting GrantInstitution d’accueil
37073 Gottingen
Allemagne