Division of Plant and Cop Sciences, The University of Nottingham, Sutton Bonington Campus, Loughborough, Leicestershire, UK.
Cereal Genomics Lab, Life Sciences Building, School of Biological Sciences, University of Bristol, Bristol, UK.
BMC Plant Biol. 2019 May 6;19(1):183. doi: 10.1186/s12870-019-1785-z.
Triticum timopheevii (2n = 4x = 28; AAGG), is an important source for new genetic variation for wheat improvement with genes for potential disease resistance and salt tolerance. By generating a range of interspecific hybrid lines, T. timopheevii can contribute to wheat's narrow gene-pool and be practically utilised in wheat breeding programmes. Previous studies that have generated such introgression lines between wheat and its wild relatives have been unable to use high-throughput methods to detect the presence of wild relative segments in such lines.
A whole genome introgression approach, exploiting homoeologous recombination in the absence of the Ph1 locus, has resulted in the transfer of different chromosome segments from both the A and G genomes of T. timopheevii into wheat. These introgressions have been detected and characterised using single nucleotide polymorphism (SNP) markers present on a high-throughput Axiom® Genotyping Array. The analysis of these interspecific hybrid lines has resulted in the detection of 276 putative unique introgressions from T. timopheevii, thereby allowing the generation of a genetic map of T. timopheevii containing 1582 SNP markers, spread across 14 linkage groups representing each of the seven chromosomes of the A and G genomes of T. timopheevii. The genotyping of the hybrid lines was validated through fluorescence in situ hybridisation (FISH). Comparative analysis of the genetic map of T. timopheevii and the physical map of the hexaploid wheat genome showed that synteny between the two species is highly conserved at the macro-level and confirmed the presence of inter- and intra-genomic translocations within the A and G genomes of T. timopheevii that have been previously only detected through cytological techniques.
In this work, we report a set of SNP markers present on a high-throughput genotyping array, able to detect the presence of T. timopheevii in a hexaploid wheat background making it a potentially valuable tool for marker assisted selection (MAS) in wheat pre-breeding programs. These valuable resources of high-density molecular markers and wheat-T. timopheevii hybrid lines will greatly enhance the work being undertaken for wheat improvement through wild relative introgressions.
节节麦（2n = 4x = 28；AAGG）是小麦改良的重要遗传资源，具有潜在的抗病和耐盐基因。通过产生一系列种间杂交系，节节麦可以丰富小麦的狭窄基因库，并在小麦育种计划中实际应用。以前的研究已经在小麦与其野生近缘种之间产生了这种基因渗入系，但无法使用高通量方法来检测这些系中野生近缘种片段的存在。
利用同源重组而不存在 Ph1 基因座的全基因组基因渗入方法，已经将节节麦的 A 和 G 基因组的不同染色体片段转移到小麦中。这些渗入片段已通过存在于高通量 Axiom®基因分型阵列上的单核苷酸多态性（SNP）标记进行检测和表征。对这些种间杂交系的分析导致检测到来自节节麦的 276 个假定独特的基因渗入，从而生成了包含 1582 个 SNP 标记的节节麦遗传图谱，这些标记分布在 14 个连锁群上，代表节节麦的 A 和 G 基因组的 7 条染色体。通过荧光原位杂交（FISH）对杂交系的基因型进行了验证。节节麦遗传图谱和六倍体小麦基因组物理图谱的比较分析表明，两个物种之间的同线性在宏观水平上高度保守，并证实了节节麦 A 和 G 基因组中存在种间和种内易位，这些易位以前仅通过细胞学技术检测到。
在这项工作中，我们报告了一组存在于高通量基因分型阵列上的 SNP 标记，能够在六倍体小麦背景下检测到节节麦的存在，使其成为小麦标记辅助选择（MAS）的潜在有用工具。这些高密度分子标记和小麦-节节麦杂交系的宝贵资源将极大地增强通过野生近缘种基因渗入进行小麦改良的工作。
