Is ancient polymorphsism in R genes maintained through diffuse interactions across species sharing similar microbiomes? We know from our experiences in agriculture that resistance is seldom durable. On average, pests overcome resistance traits within three to five years. However, in nature, resistance alleles can persist for millions of years and retain functionality. Why is this? One likely factor is that agricultural fields are simple monocultures, often dominated by single pests. Nature, on the other hand, is complex with dozens of host plants sharing thousands of microbial associates. Recent work has unraveled how long-term variation at one particular resistance gene is maintained by these complex and diffuse interactions. Coevolutionary dynamics on resistance genes may be integrated across groups of species.
In this work, I aim to determine the extent to which selection on resistance is shared among co-occurring host plants by exploring whether they share the same evolutionary histories for a variety of resistance genes. I will work in close collaboration with Fabrice Roux at the Laboratory of Plant Microbe Interactions (LPMI) in Toulouse, France. His collection of natural French populations of the model plant Arabidopsis thaliana, and two related naturally co-occurring Brassicaceae species (Cardamine hirsuta and Erophila verna) will be the source material for comparative genomics on resistance genes. If these species share the same evolutionary histories in relation to resistance genes, this may inform the use of community complexity as a means of extending the durability of resistance.