Department of Agronomy & Plant Breeding, Faculty of Agriculture, University of Zanjan, Zanjan, Iran.
Breeding Material Development Unit, Institute of Crop Science, National Agriculture and Food Research Organization (NARO), Tsukuba, Ibaraki, Japan.
PLoS One. 2020 Apr 16;15(4):e0230820. doi: 10.1371/journal.pone.0230820. eCollection 2020.
The high toxicity of cadmium (Cd) and its ready uptake by plants has become a major agricultural problem. To investigate the genetic architecture and genetic regulation of Cd tolerance in barley, we conducted quantitative trait loci (QTL) analysis in the phenotypically polymorphic Oregon Wolfe Barley (OWB) mapping population, derived from a cross between Rec and Dom parental genotypes. Through evaluating the Cd tolerance of 87 available doubled haploid lines of the OWB mapping population at the seedling stage, one minor and one major QTL were detected on chromosomes 2H and 6H, respectively. For chlorosis and necrosis traits, the major QTL explained 47.24% and 38.59% of the phenotypic variance, respectively. RNA-Seq analysis of the parental seedlings under Cd treatment revealed 542 differentially expressed genes between Cd-tolerant Rec and Cd-susceptible Dom genotypes. By analyzing sequence variations in transcribed sequences of the parental genotypes, 155,654 SNPs and 1,525 InDels were identified between the two contrasting genotypes and may contribute to Cd tolerance. Finally, by integrating the data from the identified QTLs and RNA-Seq analysis, 16 Cd tolerance-related candidate genes were detected, nine of which were metal ion transporters. These results provide promising candidate genes for further gene cloning and improving Cd tolerance in barley.
镉（Cd）的高毒性及其被植物易吸收的特性，使其成为一个主要的农业问题。为了研究大麦对镉耐受性的遗传结构和遗传调控，我们对来自 Rec 和 Dom 亲本基因型杂交衍生的表型多态性俄勒冈沃尔夫大麦（OWB）作图群体进行了数量性状位点（QTL）分析。通过评估 OWB 作图群体中 87 个可用的加倍单倍体系在幼苗期的镉耐受性，在第 2H 和第 6H 染色体上分别检测到一个小的和一个大的 QTL。对于黄化和坏死性状，主 QTL 分别解释了 47.24%和 38.59%的表型方差。Cd 处理下亲本幼苗的 RNA-Seq 分析显示，Cd 耐受型 Rec 和 Cd 敏感型 Dom 基因型之间有 542 个差异表达基因。通过分析亲本基因型转录序列中的序列变异，在两个对比基因型之间鉴定出 155654 个 SNPs 和 1525 个 InDels，它们可能与 Cd 耐受性有关。最后，通过整合鉴定的 QTL 和 RNA-Seq 分析的数据，检测到 16 个与 Cd 耐受性相关的候选基因，其中 9 个是金属离子转运蛋白。这些结果为进一步克隆基因和提高大麦的 Cd 耐受性提供了有希望的候选基因。
