[Chih-Hang Wu] The origin of a complex plant immune receptor network
POST:
NRC0 gene cluster is conserved among carrots, coffee, sweet potato, and tomato genomes.
Plants use nucleotide-binding domain and leucine-rich repeat-containing proteins (NLRs) as intracellular immune receptors to recognize pathogen effectors and limit pathogen spread. While some NLRs act as singletons, many are specialized into sensor NLRs that detect pathogen effectors and helper NLRs that mediate immune responses. In solanaceous plants, the NRC network consists of such sensor and helper NLRs. In this study, we used phylogenomics to trace the evolution of the NRC family. We discovered that NRC0 is the only NRC family member shared across asterid plants and is often clustered with other NRC-dependent sensor NLRs. This led us to hypothesize that the ancestral NRC network was an NLR helper–sensor gene cluster present early in asterid evolution. We validated this hypothesis by showing that NRC0 is crucial for the hypersensitive cell death triggered by its linked sensor NLR partners in tomato, wild sweet potato, coffee, and carrot. Additionally, sensor NLR activation induces complex formation of NRC0, similar to other NRCs. Our findings illustrate the evolutionary dynamics of the NRC network over 125 million years, evolving from a conserved gene cluster to a dispersed network.
This project was conducted in collaboration with Dr. Hiroaki Adachi (Kyoto University, Japan) and Dr. Sophien Kamoun (The Sainsbury Laboratory, UK).