Good understanding of the genes controlling root development is required to engineer root systems better adapted to different soil types. In wheat (Triticum aestivum L.), the 1RS.1BL wheat–rye (Secale cereale L.) translocation has been associated with improved drought tolerance and a large root system. However, an isogenic line carrying an interstitial segment from wheat chromosome arm 1BS in the distal region of the 1RS arm (1RS^RW) showed reduced grain yield and shorter roots both in the field and in hydroponic cultures relative to isogenic lines with the complete 1RS arm. In this study, we used exome capture to characterize 1RS^RW and its parental lines T‐9 and 1B+40. We show that 1RS^RW has a 7.0 Mb duplicated 1RS region and a 4.8 Mb 1BS insertion colinear with the 1RS duplication, resulting in triplicated genes. Lines homozygous for 1RS^RW have short seminal roots, while lines heterozygous for this chromosome have roots of intermediate length. By contrast, near‐isogenic lines carrying only the 1BS distal region or the 1RS‐1BS duplication have long seminal roots similar to 1RS, suggesting a limited effect of the 1BS genes. These results suggest that the dosage of duplicated 1RS genes is critical for seminal root length. An induced deletion encompassing 38 orthologous wheat and rye duplicated genes restored root length and confirmed the importance of gene dosage in the short‐root phenotype. We explored the expression profiles and functional annotation of these genes and discuss their potential as candidate genes for the regulation of seminal root length in wheat.

中文翻译：

---

小麦 (1BS)-黑麦 (1RS) 重组染色体的结构重排影响基因剂量和根长

需要对控制根发育的基因有充分的了解，才能更好地适应不同土壤类型的根系。在小麦 ( Triticum aestivum L.) 中，1RS.1BL 小麦-黑麦 ( Secale graine L.) 易位与提高的耐旱性和大的根系有关。然而，与具有完整 1RS 臂的等基因系相比，在 1RS 臂 (1RS ^RW ) 的远端区域携带来自小麦染色体臂 1BS 的间质片段的等基因系在田间和水培培养中显示出谷物产量降低和根较短。 . 在这项研究中，我们使用外显子组捕获来表征 1RS ^RW及其亲本系 T-9 和 1B+40。我们证明了 1RS ^RW有一个 7.0 Mb 重复的 1RS 区域和一个与 1RS 重复共线的 4.8 Mb 1BS 插入，导致三倍基因。1RS ^RW纯合系具有短的精根，而该染色体的杂合系具有中等长度的根。相比之下，仅携带 1BS 远端区域或 1RS-1BS 重复的近等基因系具有与 1RS 相似的长精根，表明 1BS 基因的作用有限。这些结果表明，重复 1RS 基因的剂量对精根长度至关重要。包含 38 个直系同源小麦和黑麦重复基因的诱导缺失恢复了根长，并证实了基因剂量在短根表型中的重要性。我们探索了这些基因的表达谱和功能注释，并讨论了它们作为调节小麦精根长度的候选基因的潜力。