Meiotic homoeologous recombination-based alien gene introgression in the genomics era of wheat

Abstract

Wheat (Triticum spp.) has a narrow genetic basis due to its allopolyploid origin. However, wheat has numerous wild relatives usable for expanding genetic variability of its genome through meiotic homoeologous recombination. Traditionally, laborious cytological analyses have been employed to detect homoeologous recombination. This has limited the progress of alien gene introgression in wheat improvement. Here, we used the ph1b mutant and high-throughput genotyping technologies to identify and facilitate homoeologous recombination-based alien gene introgression. Genotypes homozygous for ph1b and heterozygous for wheat chromosome 2B and its homoeologue in the wild species Aegilops speltoides Tausch (2S) and Thinopyrum elongatum (Host) D. R. Dewey (2E) were constructed to enhance 2B–2S and 2B–2E meiotic pairing and recombination. Backcross populations were subsequently developed to effectively recover and detect 2B–2S and 2B–2E homoeologous recombination events using the high-throughput, chip-based single-nucleotide polymorphism (SNP) assay and uniplex SNP-derived polymerase chain reaction (PCR) markers. This DNA marker-mediated approach will enhance the recovery and detection of meiotic homoeologous recombination for alien gene introgression and boost the utilization of alien genes in wheat improvement.