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Abstract

Infectious disease is not only a major force of selection in nature, but also a prime cause of yield loss in agriculture. In plants, resistance to disease is often conferred by nucleotide-binding leucine-rich repeat (NLR) proteins, intracellular immune receptors that recognize pathogen proteins and their effects on the host. Consistent with both rampant balancing and positive selection, NLRs are encoded by one of the most variable gene families in plants, but the true extent of intraspecific NLR diversity has been unclear. Here, we define a nearly saturated species-wide pan-NLRome in Arabidopsis thaliana based on sequence enrichment and long-read sequencing. We infer that the pan-NLRome saturates with approximately 40 accessions, with half of the pan-NLRome being present in most accessions. We chart the architectural diversity of NLR proteins, identify new architectures, and quantify selective forces that act on specific NLRs and domains. Our study provides a blueprint for defining the pan-NLRomes of plant species. I will focus on the population genetic properties of the Arabidopsis pan-NLRome and further discuss our ongoing efforts to sequence, analyze and compare pan-NLRomes from domesticated paleopolyploid Brassica species with the model system.