Fibre strength (FS) is an important quality attribute in the modern textile industry, which is genetically controlled by quantitative trait loci (QTLs). Fine-mapping stable QTLs for FS to identify candidate genes would be valuable for uncovering the genetic basis of fibre quality traits in cotton. Here, a single segment introgression line, IL-D2-2, from the cross of (TM-1×TX-1046) reported in our previous studies, was found to have significantly improved FS compared with the recurrent parent TM-1. To fine-map the QTLs of the FS, we further crossed IL-D2-2 with its recurrent parent TM-1 to produce F2 and F2:3 populations. QTL analysis and substitution mapping showed qFS-Chr. D02 was anchored into a 550.66 kb-interval between two markers, INTR1027 and JESPR-231. This interval contained 67 genes, among which 27 genes related to cell-wall synthesis were selected to conduct qRT-PCR. The results revealed seven genes were expressed significantly differently during the fibre secondary-wall-thickening stage (10-25 days post-anthesis), three being upregulated and four downregulated in IL-D2-2. Both GH_D02G2269 (UDP-glucosyl transferase 84B1) and GH_D02G2289 (unknown function (DUF869)) with nonsynonymous SNPs in IL-D2-2 had significantly downregulated expression, suggesting they were candidates for qFS-Chr. D02. This research provides information about marker-assisted selection for cotton fibre strength improvement.

中文翻译：

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qFS-Chr 的精细定位和候选基因分析。D02，从半野生棉花渗入陆地棉的纤维强度 QTL

纤维强度（FS）是现代纺织工业中的重要质量属性，受数量性状位点（QTL）基因控制。精细定位 FS 的稳定 QTL 以识别候选基因对于揭示棉花纤维品质性状的遗传基础具有重要价值。在这里，发现来自我们之前研究中报道的 (TM-1×TX-1046) 杂交的单节段基因渗入系 IL-D2-2 与复发亲本 TM-1 相比具有显着改善的 FS。为了精细定位 FS 的 QTL，我们进一步将 IL-D2-2 与其循环亲本 TM-1 杂交以产生 F2 和 F2:3 种群。QTL 分析和替代作图显示 qFS-Chr。D02 被锚定在两个标记 INTR1027 和 JESPR-231 之间的 550.66 kb 间隔中。这个区间包含 67 个基因，其中选择与细胞壁合成相关的27个基因进行qRT-PCR。结果显示，在纤维次生壁增厚阶段（开花后 10-25 天），7 个基因的表达显着不同，IL-D2-2 中 3 个基因上调，4 个基因下调。在 IL-D2-2 中具有非同义 SNP 的 GH_D02G2269（UDP-葡萄糖基转移酶 84B1）和 GH_D02G2289（未知功能（DUF869））的表达显着下调，表明它们是 qFS-Chr 的候选者。D02. 这项研究提供了有关棉花纤维强度改进的标记辅助选择的信息。在 IL-D2-2 中，三个被上调，四个被下调。在 IL-D2-2 中具有非同义 SNP 的 GH_D02G2269（UDP-葡萄糖基转移酶 84B1）和 GH_D02G2289（未知功能（DUF869））的表达显着下调，表明它们是 qFS-Chr 的候选者。D02. 这项研究提供了有关棉花纤维强度改进的标记辅助选择的信息。在 IL-D2-2 中，三个被上调，四个被下调。在 IL-D2-2 中具有非同义 SNP 的 GH_D02G2269（UDP-葡萄糖基转移酶 84B1）和 GH_D02G2289（未知功能（DUF869））的表达显着下调，表明它们是 qFS-Chr 的候选者。D02. 这项研究提供了有关棉花纤维强度改进的标记辅助选择的信息。