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NOD-Like Receptor Genes Undergo Diversity-Enhancing Evolution in a Fungal Species Complex
S Lorena Ament-Velásquez1, Sven J Saupe2
1Department of Zoology, Stockholm University, Stockholm 106 91, Sweden.
Genome Biology and Evolution
|July 23, 2026
Summary
Fungal NOD-like receptors (NLRs) evolve rapidly, suggesting a broad immune role. Specific NLRs with high internal conservation (HIC) show unique evolutionary patterns, including repeat shuffling, enhancing immune diversity.
Area of Science:
- Mycology
- Evolutionary Biology
- Immunology
Background:
- Fungi possess diverse NOD-like receptors (NLRs), crucial intracellular immune proteins.
- While some fungal NLRs regulate cell death during self/non-self recognition, most functions are unknown.
Purpose of the Study:
- To investigate the evolutionary dynamics of NLR genes in the Podospora anserina species complex.
- To understand the functional implications of NLR evolution, particularly concerning immune responses.
Main Methods:
- Comparative genomics analysis of NLR repertoires.
- Phylogenetic analyses and evolutionary rate estimations (dN/dS, Tajima's D).
- Investigation of associations with transposable elements and repeat-induced point mutation (RIP).
Main Results:
- Most fungal NLRs possess effector domains for regulated cell death (RCD).
- NLR genes exhibit accelerated evolution, higher gene turnover, and rapid rates compared to other genes.
- A distinct subgroup, high internal conservation (HIC) NLRs, shows evidence of balancing selection, introgression, and repeat shuffling, leading to increased allelic diversity.
Conclusions:
- Fungal NLRs evolve under mechanisms that enhance diversity, consistent with a general immune function.
- HIC NLR evolution, including repeat shuffling, generates novel binding specificities and contributes to immune adaptation.
- NLR-like genes with HIC repeats are found beyond fungi, suggesting conserved evolutionary dynamics in other taxa.
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