Table_2_Identifying Candidate Genes for Enhancing Grain Zn Concentration in Wheat.DOCX

Wheat (Triticum aestivum L.) is one of the major staple food crops worldwide. Despite efforts in improving wheat quality, micronutrient levels are still below the optimal range for human nutrition. In particular, zinc (Zn) deficiency is a widespread problem in human nutrition in countries relying mainly on a cereal diet; hence improving Zn accumulation in grains is an imperative need. This study was designed to understand the genetic architecture of Zn grain concentrations in wheat grains. We performed a genome-wide association study (GWAS) for grain Zn concentrations in 369 European wheat genotypes, using field data from 3 years. The complete wheat panel was genotyped by high-density arrays of single nucleotide polymorphic (SNP) markers (90k iSELECT Infinium and 35k Affymetrix arrays) resulting in 15,523 polymorphic markers. Additionally, a subpanel of 183 genotypes was analyzed with a novel 135k Affymetrix marker array resulting in 28,710 polymorphic SNPs for high-resolution mapping of the potential genomic regions. The mean grain Zn concentration of the genotypes ranged from 25.05–52.67 μg g-1 dry weight across years with a moderate heritability value. Notably, 40 marker-trait associations (MTAs) were detected in the complete panel of varieties on chromosomes 2A, 3A, 3B, 4A, 4D, 5A, 5B, 5D, 6D, 7A, 7B, and 7D. The number of MTAs in the subpanel was increased to 161 MTAs whereas the most significant and consistent associations were located on chromosomes 3B (723,504,241–723,611,488 bp) and 5A (462,763,758–466,582,184 bp) having major effects. These genomic regions include newly identified putative candidate genes, which are related to Zn uptake and transport or represent bZIP and mitogen-activated protein kinase genes. These findings provide the basis for understanding the genetic background of Zn concentration in wheat grains that in turn may help breeders to select high Zn-containing genotypes to improve human health and grain quality.

小麦（Triticum aestivum L.）是全球主要的粮食作物之一。尽管在提升小麦品质方面已付出诸多努力，但其微量元素含量仍未能达到人类营养所需的理想水平。特别是，锌（Zn）的缺乏在以谷物为主食的国家中成为人类营养领域的普遍问题；因此，提高谷物中锌的积累量成为一项紧迫的需求。本研究旨在探究小麦籽粒中锌浓度遗传结构。我们对369个欧洲小麦基因型进行了全基因组关联分析（GWAS），利用三年来的田间数据。通过高密度单核苷酸多态性（SNP）标记数组（90k iSELECT Infinium和35k Affymetrix数组）对完整小麦基因组进行了基因分型，产生了15,523个多态性标记。此外，通过一种新型的135k Affymetrix标记数组对183个基因型的子集进行了分析，从而得到了28,710个多态性SNP，以实现潜在基因组区域的精细图谱绘制。各基因型籽粒中锌的平均浓度在历年间波动于25.05–52.67 μg g-1 干重，具有中等遗传力值。值得注意的是，在完整品种面板中检测到了40个标记-性状关联（MTA），分布在2A、3A、3B、4A、4D、5A、5B、5D、6D、7A、7B和7D染色体上。在子面板中，MTA的数量增加至161个，其中最显著且一致的关联位于3B染色体（723,504,241–723,611,488碱基对）和5A染色体（462,763,758–466,582,184碱基对），具有显著影响。这些基因组区域包含新发现的潜在候选基因，它们与锌的吸收和转运相关，或代表bZIP和丝裂原活化蛋白激酶基因。这些发现为理解小麦籽粒中锌浓度的遗传背景提供了基础，进而可能帮助育种者选择高锌含量的基因型，以改善人类健康和谷物品质。