biostudies-literatureUnknown13Herridge RSelf-incompatibility (SI) is a feature of many flowering plants, whereby self-pollen is recognized and rejected by the stigma. In grasses (Poaceae), the genes controlling this phenomenon have not been fully elucidated. Grasses have a unique two-locus system, in which two independent genetic loci (S and Z) control self-recognition. S and Z are thought to have arisen from an ancient duplication, common to all grasses. With new chromosome-scale genome data, we examined the genes present at S- and Z-loci, firstly in ryegrass (<i>Lolium perenne</i>), and subsequently in ~20 other grass species. We found that two DUF247 genes and a short unstructured protein (SP/ZP) were present at both S- and Z- in all SI species, while in self-compatible species these genes were often lost or mutated. ExpressiFrontiers in plant science1011299https://www.ebi.ac.uk/biostudies/studies/S-EPMC9623065biostudies-literatureIdentification of the genes at <i>S</i> and <i>Z</i> reveals the molecular basis and evolution of grass self-incompatibility.PMC9623065McCourt TBrownfield LMacknight RJacobs JMEHerridge RMace PfalseIdentification of the genes at <i>S</i> and <i>Z</i> reveals the molecular basis and evolution of grass self-incompatibility.Self-incompatibility (SI) is a feature of many flowering plants, whereby self-pollen is recognized and rejected by the stigma. In grasses (Poaceae), the genes controlling this phenomenon have not been fully elucidated. Grasses have a unique two-locus system, in which two independent genetic loci (S and Z) control self-recognition. S and Z are thought to have arisen from an ancient duplication, common to all grasses. With new chromosome-scale genome data, we examined the genes present at S- and Z-loci, firstly in ryegrass (<i>Lolium perenne</i>), and subsequently in ~20 other grass species. We found that two DUF247 genes and a short unstructured protein (SP/ZP) were present at both S- and Z- in all SI species, while in self-compatible species these genes were often lost or mutated. Expressi2022-01-01T00:00:00Z20222026-05-27T20:39:42.095Z2025-04-21T14:11:55.619ZS-EPMC96230653633027010.3389/fpls.2022.1011299