The Microbial Fingerprint of Drought: Patterns and Drivers of Microbiome Assembly in the Rhizosphere of Water-Stressed Plants

In this thesis, we study the behaviour of microbial communities surrounding plant roots (named rhizosphere) under drought conditions. By comparing rhizosphere communities between different plant species, we show that certain types of microbes (bacteria and fungi) are consistently enriched, and others depleted, under drought compared to well-watered conditions. On the other hand, our results also show some trends in the rhizosphere that are specific to certain plant species. As plants can shape their rhizosphere microbiome by secreting specific molecules from the roots, we further performed chemical analyses of root material to determine which molecules may be used by plants to recruit or deter specific rhizosphere bacteria and fungi. Lastly, we performed a study linking the DNA of different tomato varieties to their rhizosphere microbiome, to discover plant genetic factors potentially involved in the interaction with microbes.