< i > het-B < /i > allorecognition in < i > Podospora anserina < /i > is determined by pseudo-allelic interaction of genes encoding a HET and lectin fold domain protein and a PII-like protein

by Corinne Clav é, Sonia Dheur, Sandra Lorena Ament-Velásquez, Alexandra Granger-Farbos, Sven J. Saupe

Filamentous fungi display allorecognition genes that trigger regulated cell death (RCD) when strains of unlike genotype fuse.Podospora anserina is one of several model species for the study of this allorecognition process termed heterokaryon or vegetative incompatibility. Incompatibility restricts transmission of mycoviruses between isolates. InP.anserina, genetic analyses have identified nine incompatibility loci, termedhet loci. Here we set out to clone the genes controllinghet-B incompatibility.het-B displays two incompatible alleles,het-B1 andhet-B2. We find that thehet-B locus encompasses two adjacent genes,Bh andBp that exist as highly divergent allelic variants (Bh1/Bh2 andBp1/Bp2) in the incompatible haplotypes.Bh encodes a protein with an N-terminal HET domain, a cell death inducing domain bearing homology to Toll/interleukin-1 receptor (TIR) domains and a C-terminal domain with a predicted lectin fold. TheBp product is homologous to PII-like proteins, a family of small trimeric proteins acting as sensors of adenine nucleotides in bacteria. We show that although thehet-B system appears genetically allelic, incompatibility is in fact determined by the non-allelicBh1/Bp2 interaction while the reciprocalBh2/Bp1 interaction plays no role in incompatibility. The highly divergent C-terminal lectin fold domain of BH determines recognition specificity. Population studies...

Source: PLoS Genetics - February 12, 2024 Category: Genetics & Stem Cells Authors: Corinne Clav é Source Type: research