Large-scale structural variations induced by transposable elements promote population-specific divergence in Triticum...

Large-scale structural variations (SVs) are significant drivers of genome evolution and crop adaptation, yet they remain poorly explored in wheat due to the complexity of its large, allopolyploid genome. Wild emmer wheat (Triticum turgidum ssp. dicoccoides), the direct progenitor of domesticated wheat, serves as a vital reservoir of genetic diversity. In this study, we performed a comparative genomic analysis using high-quality assemblies of wild emmer (accession Zavitan) and bread wheat (cv. Chinese Spring) to identify and characterize large-scale SVs and their association with transposable elements (TEs).

We identified 17 large-scale genome-specific SVs, ranging in size from 1 kb to 1 Mb, many of which were associated with Gypsy and Copia retrotransposons. PCR-based genotyping of 17 loci across 68 wild emmer wheat accessions from seven geographically distinct populations validated these variations as highly polymorphic, with several showing strong population-specific distributions. Most identified SVs encompass high-confidence genes, including those encoding disease resistance kinases (e.g., LR10-like) and metabolic enzymes (e.g., anthranilate O-methyltransferase), suggesting that these structural rearrangements might be associated with functional diversity and potential environmental adaptation in the Fertile Crescent.

Our findings highlight the significant role of TE-mediated rearrangements in generating structural diversity within the wheat genome. The identification of gene-containing SVs that are specific to certain wild emmer populations underlines the potential of wild progenitors for discovering novel alleles for wheat improvement and environmental resilience.