Unravelling the molecular evolution of plant-microbiome interactions in drylands

Introduction

How plants evolved to shape their microbiota is a long-standing question in ecology and evolution. I posit that the microbiome forms a crucial part of how plants adapt to changing environments and that this microbiota optimization should be manifested in a strong genomic and phenotypic signature of adaptation.

Research Proposal

I propose to use natural plant variation and biogeography to dissect how plants evolved along with their microbiota to cope with aridity. Eight within-genus pairs of Brassicaceae species have been identified, distributed vicariously across a steep precipitation gradient. These species pairs represent eight independent instances of adaptation to aridity.

Study Framework

This natural distribution offers an excellent framework for studying the evolution of plant-microbe interactions under arid conditions. My team will carry out an eco-evolutionary common garden experiment to compare the microbiomes of all 16 of these species under drought stress.

Experimental Design

By combining this experimental design with microbiome de-construction and gene deletion experiments, my lab will:

1. Test the hypothesis that microbially-induced drought resistance in plants is an evolutionary trait encoded in plant genomes.
2. Identify the mechanisms that bacteria employ to protect plants from drought.
3. Investigate how desert plants attract beneficial bacteria.

Importance of Microbiota Optimization

The sessility of plants dictates a particularly strong need for microbiota optimization in order to respond to a dynamic environment when there is no option to flee. Microbes are known to protect plants from drought stress, and plants are known to enrich particular microbes when stressed, but how these processes are linked remains unknown.

Conclusion

This proposal is designed to establish this link by using our extensive knowledge on plant distribution to guide the study of the plant microbiome. Successful implementation will establish if and to what extent plants evolved to supplement their own genomes with those of their microbiota to cope with challenging environments.