Abstract：
CONCLUSIONS: Meta-analysis in wheat for three major quality traits identified 110 meta-QTL (MQTL) with reduced confidence interval (CI). Five GWAS validated MQTL (viz., 1A.1, 1B.2, 3B.4, 5B.2, and 6B.2), each involving more than 20 initial QTL and reduced CI (95%) (< 2 cM), were selected for quality breeding programmes. Functional characterization including candidate gene mining and expression analysis discovered 44 high confidence candidate genes associated with quality traits. A meta-analysis of quantitative trait loci (QTL) associated with dough rheology properties, nutritional traits, and processing quality traits was conducted in wheat. For this purpose, as many as 2458 QTL were collected from 50 interval mapping studies published during 2013-2020. Of the total QTL, 1126 QTL were projected onto the consensus map saturated with 249,603 markers which led to the identification of 110 meta-QTL (MQTL). These MQTL exhibited an 18.84-fold reduction in the average CI compared to the average CI of the initial QTL (ranging from 14.87 to 95.55 cM with an average of 40.35 cM). Of the 110, 108 MQTL were physically anchored to the wheat reference genome, including 51 MQTL verified with marker-trait associations (MTAs) reported from earlier genome-wide association studies. Candidate gene (CG) mining allowed the identification of 2533 unique gene models from the MQTL regions. In-silico expression analysis discovered 439 differentially expressed gene models with > 2 transcripts per million expressions in grains and related tissues, which also included 44 high-confidence CGs involved in the various cellular and biochemical processes related to quality traits. Nine functionally characterized wheat genes associated with grain protein content, high-molecular-weight glutenin, and starch synthase enzymes were also found to be co-localized with some of the MQTL. Synteny analysis between wheat and rice MQTL regions identified 23 wheat MQTL syntenic to 16 rice MQTL associated with quality traits. Furthermore, 64 wheat orthologues of 30 known rice genes were detected in 44 MQTL regions. Markers flanking the MQTL identified in the present study can be used for marker-assisted breeding and as fixed effects in the genomic selection models for improving the prediction accuracy during quality breeding. Wheat orthologues of rice genes and other CGs available from MQTLs can be promising targets for further functional validation and to better understand the molecular mechanism underlying the quality traits in wheat.
摘要：
结论：在小麦三个主要品质性状的Meta分析中，鉴定出110个置信区间（CI）降低的meta-QTL（MQTL）。五个GWAS验证的MQTL(即,1A.1,1B.2,3B.4,5B.2和6B.2),每个涉及超过20个初始QTL和减少的CI(95%)(<2cM)，被选入优质育种计划。包括候选基因挖掘和表达分析在内的功能表征发现了44个与质量性状相关的高置信度候选基因。与面团流变学特性相关的数量性状位点（QTL）的荟萃分析，营养性状，并对小麦的加工品质性状进行了研究。为此,从2013-2020年发表的50项区间作图研究中收集了多达2458个QTL.在总QTL中，将1126个QTL投影到具有249,603个标记的共有图谱上，从而鉴定出110个元QTL（MQTL）。与初始QTL的平均CI相比，这些MQTL的平均CI降低了18.84倍（范围为14.87至95.55cM，平均为40.35cM）。在110个MQTL中，108个MQTL被物理锚定到小麦参考基因组，包括通过早期全基因组关联研究报告的标记-性状关联（MTA）验证的51个MQTL。候选基因（CG）挖掘允许从MQTL区域鉴定2533个独特的基因模型。计算机表达分析发现439个差异表达基因模型，在谷物和相关组织中每百万表达>2个转录本，其中还包括44个高置信度CG，涉及与质量性状相关的各种细胞和生化过程。与谷物蛋白质含量相关的九个功能特征小麦基因，高分子量谷蛋白,还发现淀粉合酶与一些MQTL共定位。小麦和水稻MQTL区域之间的合成分析确定了23个小麦MQTL与16个水稻MQTL与品质性状相关。此外，在44个MQTL区域检测到30个已知水稻基因的64个小麦直系同源物。本研究中鉴定的MQTL侧翼标记可用于标记辅助育种，并在基因组选择模型中用作固定效应，以提高优质育种过程中的预测准确性。来自MQTL的水稻基因和其他CGs的小麦直系同源物可以成为进一步功能验证和更好地了解小麦品质性状背后的分子机制的有希望的目标。
