Comparative Analysis of Plant Immune Receptor Architectures Uncovers Host Proteins Targeted By Pathogens

Plants deploy immune receptors to detect pathogen-derived molecules and initiate defense responses. Intracellular plant immune receptors called NLRs contain a central Nucleotide Binding domain followed by a series of Leucine rich Repeats, and are key initiators of plant defense responses. However, recent studies demonstrated that NLRs with non-canonical domain architectures play an important role in plant immunity. These composite immune receptors are thought to arise from fusions between NLRs and additional domains that serve as baits for the pathogen-derived effector proteins, thus enabling pathogen recognition.We have scanned available plant genome sequences for the full spectrum of NLR-fusion events to evaluate the diversity of such integrations of potential sensor domains across flowering plants, including 19 crop species. We manually curated wheat and brassicas and experimentally validated a subset of fusions in wild and cultivated wheat varieties. We have examined NLR fusions that occur in multiple plant families and identified that some domains show re-occurring integration across lineages. Proteins fused to NLRs overlap with previously identified pathogen targets confirming that they act as ‘baits’ for the pathogen. While some fusions have been previously implicated in disease resistance, others provide new targets for engineering durable resistance to plant pathogens. We have built a robust reproducible pipeline for detecting variable domain architectures in plant immune receptors across species. We hypothesize that NLR-fusions we reveal provide clues to the host proteins targeted by pathogens and that this information can be deployed to discover new sources of disease resistance.

This abstract and project presents original unpublished work which is curently in review for publication