Ph2 encodes the mismatch repair protein MSH7-3D that inhibits wheat homoeologous recombination

• DOI: 10.1038/s41467-021-21127-1
• Publication Date: 2021-02-05T11:24:30Z
• Authors: Heïdi Serra; Radim Svačina; Ute Baumann; Ryan Whitford; Tim Sutton; Jan Bartoš; Pierre Sourdille
• Keywords: DNA, Plant; [SDV]Life Sciences [q-bio]; Science; Gene Expression; MESH: Triticum / genetics; DNA Mismatch Repair; Article; Chromosomes, Plant; MESH: Homologous Recombination; 03 medical and health sciences; MESH: Plant Breeding / methods; Gene Expression Regulation, Plant; [SDV.BV]Life Sciences [q-bio]/Vegetal Biology; MESH: Gene Expression Regulation, Plant; Homologous Recombination; Alleles; Triticum; Plant Proteins; 2. Zero hunger; [SDV.GEN]Life Sciences [q-bio]/Genetics; 0303 health sciences; Ploidies; Chimera; Secale; MESH: DNA, Plant / genetics; Q; Physical Chromosome Mapping; hexaploid wheat; MESH: Plant Proteins / genetics; Meiosis; Plant Breeding; Mutation

AbstractMeiotic recombination is a critical process for plant breeding, as it creates novel allele combinations that can be exploited for crop improvement. In wheat, a complex allohexaploid that has a diploid-like behaviour, meiotic recombination between homoeologous or alien chromosomes is suppressed through the action of several loci. Here, we report positional cloning of Pairing homoeologous 2 (Ph2) and functional validation of the wheat DNA mismatch repair protein MSH7-3D as a key inhibitor of homoeologous recombination, thus solving a half-century-old question. Similar to ph2 mutant phenotype, we show that mutating MSH7-3D induces a substantial increase in homoeologous recombination (up to 5.5 fold) in wheat-wild relative hybrids, which is also associated with a reduction in homologous recombination. These data reveal a role for MSH7-3D in meiotic stabilisation of allopolyploidy and provides an opportunity to improve wheat’s genetic diversity through alien gene introgression, a major bottleneck facing crop improvement.