Maize (Zea mays L.) has undergone profound changes in root anatomy for environmental adaptation during domestication. However, the genetic mechanism of plasticity of maize root anatomy during the domestication process remains unclear. In this study, high-resolution mapping was performed for nine root anatomical traits using a maize-teosinte population (mexicana × Mo17) across three environments. Large genetic variations were detected for different root anatomical traits. The cortex, stele, aerenchyma areas, xylem vessel number, and cortical cell number had large variations across three environments, indicating high plasticity. Sixteen quantitative trait loci (QTL) were identified, including seven QTL with QTL × environment interaction (EIQTL) for high plasticity traits and nine QTL without QTL × environment interaction (SQTL). Most of the root loci were consistent with shoot QTL depicting domestication signals. Combining transcriptome and genome-wide association studies revealed that AUXIN EFFLUX CARRIER PIN–FORMED LIKE 4 (ZmPILS4) serves as a candidate gene underlying a major QTL of xylem traits. The near-isogenic lines (NILs) with lower expression of ZmPILS4 had 18–24% more auxin concentration in the root tips and 8–15% more xylem vessels. Nucleotide diversity values analysis in the promoter region suggested that ZmPILS4 was involved in maize domestication and adaptation. These results revealed the potential genetic basis of root anatomical plasticity during domestication.

中文翻译：

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玉米-类蜀黍衍生种群驯化过程中根部解剖结构的可塑性

玉米 (Zea mays L.) 在驯化过程中为了适应环境而在根部解剖结构上发生了深刻变化。然而，驯化过程中玉米根部解剖结构可塑性的遗传机制仍不清楚。在这项研究中，使用 maize-teosinte 种群 (mexicana × Mo17) 在三个环境中对九个根解剖特征进行了高分辨率映射。针对不同的根解剖特征检测到较大的遗传变异。皮层、石碑、通气组织区域、木质部血管数量和皮层细胞数量在三种环境中变化很大，表明可塑性高。鉴定出16个数量性状位点（QTL），其中7个具有QTL×环境相互作用（EIQTL）的QTL具有高可塑性性状，9个QTL没有QTL×环境相互作用（SQTL）。大多数根基因座与描绘驯化信号的芽 QTL 一致。结合转录组和全基因组关联研究表明，AUXIN EFFLUX CARRIER PIN-FORMED LIKE 4 (ZmPILS4) 是木质部性状主要 QTL 的候选基因。ZmPILS4 表达较低的近等基因系 (NIL) 的根尖生长素浓度增加 18-24%，木质部血管增加 8-15%。启动子区域的核苷酸多样性值分析表明ZmPILS4参与了玉米的驯化和适应。这些结果揭示了驯化过程中根解剖可塑性的潜在遗传基础。结合转录组和全基因组关联研究表明，AUXIN EFFLUX CARRIER PIN-FORMED LIKE 4 (ZmPILS4) 是木质部性状主要 QTL 的候选基因。ZmPILS4 表达较低的近等基因系 (NIL) 的根尖生长素浓度增加 18-24%，木质部血管增加 8-15%。启动子区域的核苷酸多样性值分析表明ZmPILS4参与了玉米的驯化和适应。这些结果揭示了驯化过程中根解剖可塑性的潜在遗传基础。结合转录组和全基因组关联研究表明，AUXIN EFFLUX CARRIER PIN-FORMED LIKE 4 (ZmPILS4) 是木质部性状主要 QTL 的候选基因。ZmPILS4 表达较低的近等基因系 (NIL) 的根尖生长素浓度增加 18-24%，木质部血管增加 8-15%。启动子区域的核苷酸多样性值分析表明ZmPILS4参与了玉米的驯化和适应。这些结果揭示了驯化过程中根解剖可塑性的潜在遗传基础。启动子区域的核苷酸多样性值分析表明ZmPILS4参与了玉米的驯化和适应。这些结果揭示了驯化过程中根解剖可塑性的潜在遗传基础。启动子区域的核苷酸多样性值分析表明ZmPILS4参与了玉米的驯化和适应。这些结果揭示了驯化过程中根解剖可塑性的潜在遗传基础。