Boehm Jeffrey, Cai Xiwen
USDA-ARS, Wheat, Sorghum & Forage Research Unit, Lincoln, NE 68583, USA.
Department of Agronomy and Horticulture, University of Nebraska, Lincoln, NE 68583, USA.
Plants (Basel). 2024 Jan 23;13(3):339. doi: 10.3390/plants13030339.
Wheat, including durum and common wheat, respectively, is an allopolyploid with two or three homoeologous subgenomes originating from diploid wild ancestral species. The wheat genome's polyploid origin consisting of just three diploid ancestors has constrained its genetic variation, which has bottlenecked improvement. However, wheat has a large number of relatives, including cultivated crop species (e.g., barley and rye), wild grass species, and ancestral species. Moreover, each ancestor and relative has many other related subspecies that have evolved to inhabit specific geographic areas. Cumulatively, they represent an invaluable source of genetic diversity and variation available to enrich and diversify the wheat genome. The ancestral species share one or more homologous genomes with wheat, which can be utilized in breeding efforts through typical meiotic homologous recombination. Additionally, genome introgressions of distant relatives can be moved into wheat using chromosome engineering-based approaches that feature induced meiotic homoeologous recombination. Recent advances in genomics have dramatically improved the efficacy and throughput of chromosome engineering for alien introgressions, which has served to boost the genetic potential of the wheat genome in breeding efforts. Here, we report research strategies and progress made using alien introgressions toward the enrichment and diversification of the wheat genome in the genomics era.
小麦，包括硬粒小麦和普通小麦，分别是一种异源多倍体，具有两个或三个源自二倍体野生祖先物种的同源亚基因组。小麦基因组由仅三个二倍体祖先组成的多倍体起源限制了其遗传变异，这成为了改良的瓶颈。然而，小麦有大量的近缘种，包括栽培作物物种（如大麦和黑麦）、野草物种和祖先物种。此外，每个祖先和近缘种都有许多其他相关亚种，它们已经进化到栖息在特定的地理区域。总体而言，它们代表了丰富小麦基因组并使其多样化的宝贵遗传多样性和变异来源。祖先物种与小麦共享一个或多个同源基因组，可通过典型的减数分裂同源重组用于育种工作。此外，利用基于染色体工程的方法，通过诱导减数分裂同源重组的特性，可以将远缘种的基因组渗入到小麦中。基因组学的最新进展极大地提高了用于外源渗入的染色体工程的效率和通量，这有助于在育种工作中提升小麦基因组的遗传潜力。在此，我们报告了在基因组学时代利用外源渗入实现小麦基因组富集和多样化的研究策略及进展。
