Chromosome Synapsis and Recombination in Cereals

<jats:title>Abstract</jats:title><jats:p>Crops are under constant pressure due to climate change imposing dramatic changes in rainfall, temperature, and soil salinity. They are also under high stress due to pests and diseases, costing yield, and income loss to farmers. Thus, there is a need to create more resilient varieties. New favourable allelic combinations are achieved via homologous recombination during a process called meiosis. During meiosis, homologous chromosomes pair, synapse, and recombine; but crossover (CO) sites are rare, limiting the creation of valuable allelic recombinants. In large genome crops, such as barley or wheat, crossovers are not only scarce (2 or 3 per chromosome), they are also mainly located at the ends of the chromosomes, leaving 20–30% of genes in the pericentromeric region which breeding cannot exploit (<jats:ext-link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="https://youtu.be/XyMhyeWMZl4">https://youtu.be/XyMhyeWMZl4</jats:ext-link>). The use of downregulated lines for specific meiotic gene candidates (e.g. RECQ4) has shown successful and promising translational research from the model plant<jats:italic>Arabidopsis thaliana</jats:italic>to crops, raising hopes for using this approach in breeding programs. The development of new tools, technologies, and protocols have demonstrated new insights into the progression of meiosis crops – highlighting unique meiotic phenomena not observed in<jats:italic>Arabidopsis</jats:italic>– and revealed a higher cost of meiotic mutants on fertility than previously thought suggesting a more intricate relationship between meiotic events. In this article, we have selected a number of studies to show the relationship between synaptonemal complex formation and the recombination machinery.</jats:p>