Collaborative Research: Genes to ecology in tropical trees: how sharing resistance gene alleles affects pathogen transmission and growth

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This project examines how sharing variants of genes associated with resistance to pathogens among neighboring trees affects their susceptibility or resistance to infection by pathogenic soil microbes, and how this affects their growth in lab and forest settings. This research will also determine if variation in resistance genes impacts the beneficial as well as pathogenic microbial communities associated with tree roots. This will have important consequences for predicting the success of an individual tree depending on its proximity to individuals with the same and different variants of pathogen resistance genes. This knowledge has important implications for forest ecology and will provide new insights about the best planting arrangements for all types of plant species that have well characterized pathogen resistance genotypes. The results will also inform models that examine how species differences in the diversity of host resistance genes affect an entire forest community. The project will inform agricultural methods and contribute to sustainability of long-term ecological research in forest plots by providing new concepts, tools, hypotheses, results, training, and professional development opportunities for young scientists. The project will train post-doctoral scholars and reach out to young scientists working at Smithsonian Tropical Research Institute to mentor them on ways to include physiology and functional genomics in ecologicalStudies.Seedlings of Virola surinamensis carrying one particular resistance (R) gene allele have 20% greater growth rate when exposed to soil from mature trees lacking that allele, but no advantage when exposed to soil from mature trees carrying the same allele, with associated differences in their ability to upregulate genes involved in host defense. This project will examine how root transcriptomes, root microbiomes, cultures of pathogenic microbes, and transmission of a pathogen through different spatial networks of seedlings growing together in trays are affected by the R gene allele sharing context. Complimentary field experiments will examine performance of paired seedlings planted in different allele-sharing contexts in the forest. Complimentary monitoring studies will examine genotypes and long-term growth rates of tagged Virola surinamensis saplings and mature trees on long-term plots on Barro Colorado Island (BCI) and nearby mainland sites in Panama. The results will provide important new insights about the way genetic variation affects plant defense, plant-microbe interactions, and heretofore mechanistically vague concepts such as plant-soil feedbacks and negative density dependence that are increasingly the focus of theoretical models of forest dynamics and the maintenance of tree species diversity. An overarching feature is integration of functional genomics with data from a long-term ecological study.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.