The root system architecture (RSA) of a crop has a profound effect on the uptake of nutrients and consequently the potential yield. However, little is known about the genetic basis of RSA and resource adaptive responses in wheat (Triticum aestivum L.). Here, a high-throughput germination paper plant phenotyping system was used to identify seedling traits in a wheat doubled haploid mapping population, Savannah X Rialto. Significant genotypic and nitrate-N treatment variation was found across the population for seedling traits with distinct trait grouping for root size-related traits and root distribution-related traits. Quantitative trait locus (QTL) analysis identified a total of 59 seedling trait QTLs. Across two nitrate treatments, 27 root QTLs were specific to the nitrate treatment. Transcriptomic analyses for one of the QTLs on chromosome 2D found under low nitrate conditions was pursued revealing gene enrichment in N-related biological processes and 17 candidate up-regulated genes with possible involvement in a root angle response. Together, these findings provide genetic insight into root system architecture and plant adaptive responses to nitrate and provide targets that could help improve N capture in wheat.

中文翻译：

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六倍体小麦硝酸盐营养相关根系构型的QTL及其潜在基因的鉴定

作物的根系结构（RSA）对养分的吸收具有深远的影响，因此对潜在的产量也有深远的影响。但是，对小麦的RSA遗传基础和资源适应性反应知之甚少。在这里，使用了高通量发芽纸植物表型分析系统，以鉴定小麦加倍单倍体作图种群Savannah X Rialto的幼苗性状。在整个种群中发现了苗期性状的显着基因型和硝酸盐氮处理变异，根部大小相关性状和根系分布相关性状的性状分组也不同。数量性状基因座（QTL）分析鉴定出总共59个幼苗性状QTL。在两次硝酸盐处理中，有27个根QTL专门针对硝酸盐处理。进行了在低硝酸盐条件下发现的2D染色体QTL之一的转录组学分析，揭示了N相关生物过程中的基因富集和可能涉及根角反应的17个候选上调基因。在一起，这些发现提供了对根系体系结构和植物对硝酸盐的适应性反应的遗传见解，并提供了有助于改善小麦氮素吸收的目标。