NLR mutations suppressing immune hybrid incompatibility (Plant Physiol)

Hybrid incompatibility (HI) is effectively the opposite of hybrid vigor, and indicates a deleterious effect arising from the combination of two genomes.  Because of reduced fitness of the hybrids, HI can be considered as contributing towards speciation. In Arabidopsis thaliana, HI has been recognized in crosses between some accessions including between Landsberg (Ler) and Kashmir-2 (Kas-2). The hybrids show enhanced levels of defense gene expression, and disease resistance genes (R genes) have previously been implicated as contributing to HI. Atanasov et al. used a genetic approach to identify suppressors of Ler/Kas-2 incompatibility (sulki) mutants, which they mapped to a cluster of R genes. The authors speculate that the detrimental autoimmune phenotype could arise due to interactions between proteins encoded by the two parental loci. (Summary by Mary Williams) Plant Physiol. 10.1104/pp.18.00462