Roots perform vital roles for adaptation and productivity under water-deficit stress, even though their specific functions are poorly understood. In this study, the genetic control of the nodal-root architectural and anatomical response to water deficit were investigated among diverse spring barley accessions. Water deficit induced substantial variations in the nodal root traits. The cortical, stele, and total root cross-sectional areas of the main-shoot nodal roots decreased under water deficit, but increased in the tiller nodal roots. Root xylem density and arrested nodal roots increased under water deficit, with the formation of root suberization/lignification and large cortical aerenchyma. Genome-wide association study implicated 11 QTL intervals in the architectural and anatomical nodal root response to water deficit. Among them, three and four QTL intervals had strong effects across seasons and on both root architectural and anatomical traits, respectively. Genome-wide epistasis analysis revealed 44 epistatically interacting SNP loci. Further analyses showed that these QTL intervals contain important candidate genes, including ZIFL2, MATE, and PPIB, whose functions are shown to be related to the root adaptive response to water deprivation in plants. These results give novel insight into the genetic architectures of barley nodal root response to soil water deficit stress in the fields, and thus offer useful resources for root-targeted marker-assisted selection.

中文翻译：

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春季大麦根系结构的遗传成分和对缺水胁迫的解剖学调整。

根在缺水胁迫下对适应和生产力起着至关重要的作用，尽管人们对其根源的具体功能知之甚少。在这项研究中，研究了不同春大麦种质对节根结构和对缺水的解剖响应的遗传控制。水分亏缺导致结根性状发生显着变化。在缺水的情况下，主茎结根的皮层，石碑和总根的截面积减少，但分till结根中的根部截面积增加。在缺水条件下，根部木质部密度和停滞的节根增加，形成根部干化/木质化和大量皮质气孔。全基因组关联研究涉及11个QTL间隔在结构和解剖结根对缺水的反应中。他们之中，3个和4个QTL间隔分别在整个季节以及根部的建筑和解剖特征上都有很强的影响。全基因组上位性分析显示44个上位相互作用的SNP位点。进一步的分析表明，这些QTL区间包含重要的候选基因，包括ZIFL2，MATE和PPIB，其功能与植物对水分缺乏的根部适应性反应有关。这些结果为大麦节点根系对田间土壤水分亏缺胁迫的遗传结构提供了新的见解，从而为以根为目标的标记辅助选择提供了有用的资源。进一步的分析表明，这些QTL间隔包含重要的候选基因，包括ZIFL2，MATE和PPIB，其功能与植物对水分缺乏的根部适应性反应有关。这些结果为大麦节点根系对田间土壤水分亏缺胁迫的遗传结构提供了新的见解，从而为以根为目标的标记辅助选择提供了有用的资源。进一步的分析表明，这些QTL间隔包含重要的候选基因，包括ZIFL2，MATE和PPIB，其功能与植物对水分缺乏的根部适应性反应有关。这些结果为大麦节点根系对田间土壤水分亏缺胁迫的遗传结构提供了新的见解，从而为以根为目标的标记辅助选择提供了有用的资源。