Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Corrensstraße 3, 06466, Stadt Seeland, OT Gatersleben, Germany.
Theor Appl Genet. 2019 Nov;132(11):3035-3045. doi: 10.1007/s00122-019-03404-2. Epub 2019 Aug 3.
Novel large-effect consistent QTL for anther extrusion (AE) to improve cross-pollination were mapped in doubled haploid populations derived from IPK gene bank spring wheat accessions. TaAP2-D, an ortholog of Cleistogamy1 in barley, is a likely candidate gene for AE in wheat. To establish a robust hybrid wheat breeding system, male lines harboring alleles that promote outcrossing should be developed. In this study, we developed two doubled haploid (DH) populations of hexaploid spring wheat (Triticum aestivum L.) by crossing accessions taken from IPK gene bank. In both populations, the phenotypic data of anther extrusion (AE) based on three years of field trials showed a wide variation and approximated a normal distribution. Both populations were genotyped with a 15 k Infinium single nucleotide polymorphism (SNP) array resulting in 3567 and 3457 polymorphic SNP markers for DH population-1 and DH population-2, respectively. Composite interval mapping identified quantitative trait loci (QTL) on chromosomes 1D, 2D, 4A, 4B, 5A, 5D, 6A, and 6B; with consistent QTL (that are identified in all the years) on chromosome 4A in DH population-1, and on chromosomes 2D and 6B in DH population-2. The consistent QTL explained 17.2%, 32.9%, and 12.3% of the phenotypic variances, respectively. Genic scan of the chromosome 2D-QTL showed that the wheat gene TaAP2-D, an ortholog of Cleistogamy1 which promotes AE via swelling of the lodicules in barley, lies within the QTL region. A diagnostic marker was developed for TaAP2-D that showed co-segregation with the AE phenotype. This study shows the use of gene bank diversity reservoir to find alleles which are otherwise difficult to detect in elite populations. The identification of large-effect consistent QTL for AE is expected to help form efficient male parental lines suitable for hybrid wheat seed production and serve as a source for map-based cloning.
新型大效应一致的花粉囊开裂（AE）QTL 被定位在来自 IPK 基因库春小麦品系的双单倍体群体中，以提高异交。拟南芥 AP2-D 是大麦中的闭花授粉 1 的同源基因，是小麦中 AE 的候选基因。为了建立一个稳健的杂交小麦育种系统，应该开发携带促进异交等位基因的雄性系。在这项研究中，我们通过杂交来自 IPK 基因库的品系，开发了两个六倍体春小麦（Triticum aestivum L.）的双单倍体（DH）群体。在两个群体中，基于三年田间试验的花粉囊开裂（AE）表型数据显示出广泛的变异，并接近正态分布。两个群体都用 15k Infinium 单核苷酸多态性（SNP）芯片进行了基因型分析，结果分别为 DH 群体-1 和 DH 群体-2 产生了 3567 个和 3457 个多态 SNP 标记。复合区间作图鉴定了染色体 1D、2D、4A、4B、5A、5D、6A 和 6B 上的数量性状位点（QTL）；在 DH 群体-1 的染色体 4A 上和 DH 群体-2 的染色体 2D 和 6B 上都有一致的 QTL（在所有年份都鉴定到）。一致的 QTL 分别解释了 17.2%、32.9%和 12.3%的表型方差。对染色体 2D-QTL 的基因扫描表明，促进大麦花粉囊开裂的小麦基因 TaAP2-D 位于 QTL 区域内，TaAP2-D 是 Cleistogamy1 的同源基因。开发了一个用于 TaAP2-D 的诊断标记，该标记与 AE 表型共分离。这项研究表明，利用基因库多样性库来寻找在优良群体中难以检测到的等位基因。对花粉囊开裂的大效应一致 QTL 的鉴定有望帮助形成适合杂交小麦种子生产的有效雄性亲本系，并作为图谱克隆的来源。
