Many genes that organisms use to regulate their mutualists are also used to defend against parasites and pathogens. The shared genetic control of beneficial and harmful symbioses raises the intriguing possibility that susceptibility to infection is a pleiotropic cost of mutualism. Our goal is to understand how a genetic tradeoff between attracting mutualists and repelling parasites has shaped the genomic architecture of traits mediating species interactions, and how ongoing conflict influences adaptation.
We combine fieldwork, experiments, and genomics & transcriptomics to explore these questions in the root microbiome of legumes in the genus Medicago. Legumes rely on nitrogen provided by mutualistic bacteria (rhizobia) to grow in poor soil, but they are also infected by parasitic nematodes that steal nutrients. The two symbionts form remarkably similar structures on plant roots (below).
We've discovered that plant responses to mutualistic rhizobia and parasitic nematodes are genetically coupled in the legume Medicago. Plant genotypes that attracted more rhizobia were more heavily infected by nematodes, indicating that susceptibility to parasitic nematodes is a cost of mutualism.
We're exploring the following questions in the legume genus Medicago :
In a genetic model plant (Medicago truncatula) ...
- What are the genomic signatures of genetic conflict between mutualism and parasitism?
In a wild weed (Medicago lupulina) ...
- How does genetic conflict influence adaptation?
- How does ecology mediate genetic conflict?
In alfalfa (Medicago sativa) ...
- How can we mitigate conflict between mutualism and parasitism in crop microbiomes?
Dr. Wood received her Ph.D. in 2015 with Edmund Brodie III at the University of Virginia, performed her postdoctoral studies with John Stinchcombe at the University of Toronto, and joined the Department in 2018.