A Gene Encoding a DUF247 Domain Protein Cosegregates with the S Self-Incompatibility Locus in Perennial Ryegrass

• Published in: Molecular biology and evolution 2016-04, Vol.33 (4), p.870-884
• Main Authors: Manzanares, Chloé, Barth, Susanne, Thorogood, Daniel, Byrne, Stephen L, Yates, Steven, Czaban, Adrian, Asp, Torben, Yang, Bicheng, Studer, Bruno
• Format: Article
• Language: English
• Subjects: Amino acids; Chromosome Mapping; Economic importance; Energy crops; Flowering plants; Genes; Genetic Linkage; Genomics; Genotype; Genotypes; Grasses; High-Throughput Nucleotide Sequencing; Lolium perenne; Lolium temulentum; Plant Proteins - genetics; Plant Weeds - genetics; Poaceae; Protein Kinases - genetics; Proteins; Self-Incompatibility in Flowering Plants - genetics
• ISSN: 0737-4038; 1537-1719
• DOI: 10.1093/molbev/msv335

The grass family (Poaceae), the fourth largest family of flowering plants, encompasses the most economically important cereal, forage, and energy crops, and exhibits a unique gametophytic self-incompatibility (SI) mechanism that is controlled by at least two multiallelic and independent loci, S and Z. Despite intense research efforts over the last six decades, the genes underlying S and Z remain uncharacterized. Here, we report a fine-mapping approach to identify the male component of the S-locus in perennial ryegrass (Lolium perenne L.) and provide multiple evidence that a domain of unknown function 247 (DUF247) gene is involved in its determination. Using a total of 10,177 individuals from seven different mapping populations segregating for S, we narrowed the S-locus to a genomic region containing eight genes, the closest recombinant marker mapping at a distance of 0.016 cM. Of the eight genes cosegregating with the S-locus, a highly polymorphic gene encoding for a protein containing a DUF247 was fully predictive of known S-locus genotypes at the amino acid level in the seven mapping populations. Strikingly, this gene showed a frameshift mutation in self-compatible darnel (Lolium temulentum L.), whereas all of the self-incompatible species of the Festuca-Lolium complex were predicted to encode functional proteins. Our results represent a major step forward toward understanding the gametophytic SI system in one of the most important plant families and will enable the identification of additional components interacting with the S-locus.