Arabidopsis in succession

Summary

Terrestrial plants have the fascinating ability to locally adapt to their environment, favouring specific plant traits or genes. While this process is already quite well-understood in extreme environments, such as drought or soil pollution, much less is known about local adaptation to more subtle environmental differences. In my thesis, I have studied whether local adaptation can occur in a mild gradient of soil development during secondary succession. These soils display differences in abiotic, bacterial and fungal community composition. This was studied in a natural population of molecular model plant, Arabidopsis thaliana. I found that the Arabidopsis thaliana population is indeed in this gradient exposed to different soil compositions. In addition, despite being sampled in a relatively small area (40 km²), the population displays a huge amount of genetic variation. I showed that this population revealed a signature of local adaptation to agricultural soils, but not soils in natural development. This thesis helps to understand plant adaptation to subtle ecological gradients which improves the overall knowledge of the adaptive capacity of plants.