Genetic-based dissection of arsenic accumulation in maize using a genome-wide association analysis method

First author: Zhan Zhao; Affiliations: Henan Agricultural University (河南农业大学): Zhengzhou, China

Corresponding author: Jihua Tang (汤继华)

Understanding the mechanism of arsenic (As; 砷) accumulation in plants is important in reducing As's toxicity (毒性) to plants and its potential risks to human health. Here, we performed a genome-wide association study to dissect the genetic basis of the As contents of different maize tissues in Xixian, which was irrigated (灌溉) with As-rich surface water (地表水), and Changge using an association population consisting of 230 representative maize inbred lines. Phenotypic data revealed a wide normal distribution and high repeatability for the As contents in maize tissues. The As concentrations in maize tissues followed the same trend in the two locations: kernels (谷粒) < axes (茎轴) < stems < bracts (苞片) < leaves. In total, 15, 16 and 15 non-redundant quantitative trait loci (QTLs) associated with As concentrations were identified (P ≤ 2.04 × 10−6) in five tissues from Xixian, Changge, and the combination of the locations, respectively, explaining 9.70%–24.65% of the phenotypic variation for each QTL, on average. Additionally, four QTLs [involving 15 single nucleotide polymorphisms (SNPs)] were detected in the single and the combined locations, indicating that these loci/SNPs might be stable across different environments. The candidate genes associated with these four loci were predicted. In addition, four non-redundant QTLs (6 SNPs), including a QTL that was detected in multiple locations according to the genome-wide association study, were found to co-localize with four previously reported QTL intervals. These results are valuable to understand the genetic architecture of As mechanism in maize and facilitate the genetic improvement of varieties without As toxicity.

理解植物中砷的积累对于降低呻对于植物的毒性非常重要，并且能够潜在地降低人类健康的风险。本文基于230个玉米自交系构建的关联群体对Xixian和Changge两个品种进行了全基因组关联分析研究玉米组织中砷含量的遗传基础。表型数据显示呻含量值啊玉米组织中的广泛分布。在玉米不同组织中的呻含量排序：籽粒 < 茎轴 < 茎 < 苞片 < 叶片。作者在Xixian、Changge及组合地点共鉴定到了15、16和15个数量性状位点（QTL）与呻浓度相关，每个QTL平均解释表型变异的9.70%–24.65%。另外，4个QTLs（涉及到15个单核苷酸变异SNPs）在单个和组合地点检测到，显示这些位点或SNPs可能在不同环境中是稳定的。作者预测了与这4个位点相关的候选基因。此外，作者发现包括1个能在多个地点检测到的QTL在内的4个非冗余的QTLs（6个SNPs）与4个之前报道的QTL区间共定位。这些结果有助于进一步理解呻在玉米中积累的机制，同时促进没有呻毒性品种的遗传改良。

通讯：汤继华

个人简介：1987.09-1991.07，河南农业大学农学系学习，获学士学位；1991.09-1994.07，河南农业大学作物遗传育种专业学习，获硕士学位；1998.09-2001.07，华中农业大学作物遗传育种专业学习，获博士学位。

研究方向：玉米遗传育种。

doi: 10.1111/pbi.12853