CSIRO Agriculture and Food, Clunies Ross Street, GPO Box 1700, Canberra, ACT, 2601, Australia.
Triticeae Research Institute, Sichuan Agricultural University, 211 Huimin Road, Wenjiang, Chengdu, 611130, Sichuan, China.
Theor Appl Genet. 2023 Oct 17;136(11):226. doi: 10.1007/s00122-023-04466-z.
Lack of function of a D-genome adult plant resistance gene upon introgression into durum wheat. The wheat Lr34/Yr18/Sr57/Pm38/Ltn1 adult plant resistance gene (Lr34), located on chromosome arm 7DS, provides broad spectrum, partial, adult plant resistance to leaf rust, stripe rust, stem rust and powdery mildew. It has been used extensively in hexaploid bread wheat (AABBDD) and conferred durable resistance for many decades. These same diseases also occur on cultivated tetraploid durum wheat and emmer wheat but transfer of D genome sequences to those subspecies is restricted due to very limited intergenomic recombination. Herein we have introgressed the Lr34 gene into chromosome 7A of durum wheat. Durum chromosome substitution line Langdon 7D(7A) was crossed to Cappelli ph1c, a mutant derivative of durum cultivar Cappelli homozygous for a deletion of the chromosome pairing locus Ph1. Screening of BCF plants and their progeny by KASP and PCR markers, 90 K SNP genotyping and cytology identified 7A chromosomes containing small chromosome 7D fragments encoding Lr34. However, in contrast to previous transgenesis experiments in durum wheat, resistance to wheat stripe rust was not observed in either Cappelli/Langdon 7D(7A) or Bansi durum plants carrying this Lr34 encoding segment due to low levels of Lr34 gene expression.
小麦 Lr34/Yr18/Sr57/Pm38/Ltn1 成株期抗性基因（Lr34）的 D 基因组功能缺失，该基因位于 7DS 染色体臂上，对叶锈病、条锈病、茎锈病和白粉病具有广谱、部分成株期抗性。它已被广泛应用于六倍体普通小麦（AABBDD）中，并在几十年中提供了持久的抗性。这些相同的疾病也发生在栽培四倍体硬粒小麦和埃塞俄比亚画眉草小麦上，但由于基因组间重组非常有限，D 基因组序列向这些亚种的转移受到限制。在此，我们将 Lr34 基因导入硬粒小麦 7A 染色体。硬粒小麦染色体替代系 Langdon 7D(7A)与 Cappelli ph1c 杂交，后者是硬粒小麦品种 Cappelli 的突变体衍生物，该品种在 Ph1 染色体配对位点上纯合缺失。通过 KASP 和 PCR 标记、90 SNP 基因分型和细胞学筛选 BCF 植株及其后代，鉴定出含有编码 Lr34 的小 7D 染色体片段的 7A 染色体。然而，与硬粒小麦之前的转基因实验不同，由于 Lr34 基因表达水平低，携带该编码片段的 Cappelli/Langdon 7D(7A)或 Bansi 硬粒小麦均未观察到对小麦条锈病的抗性。
