Cadmium (Cd) is one of the heavy metal elements that are most harmful to human health, and the transmission of Cd through the food chain is a global issue. Aegilops markgrafii is a wild relative of the cultivated wheat that is tolerant of high levels of Cd. The objective of this study is to investigate the NAC transcription factors (TFs) involved in Cd tolerance in Ae. markgrafii and to verify their function in transgenic wheat. We cloned NAC TFs from Ae. markgrafii plants exposed to excessive Cd treatment. The expression profiles of NAC TFs in root and shoot tissues were examined using qRT-PCR. Transgenic wheat was obtained via Agrobacterium-mediated transformation. Finally, we examined Cd concentrations in transgenic wheat under excess Cd treatment. We identified three NAC TFs and classified them into four subfamilies. Sequence alignments showed that the NAC TFs had conserved N-terminal domains but varied C-terminal domains. Expression profiles of NAC TFs showed about 150-fold up-regulation in the transcription of AemNAC2 and AemNAC3 under excess Cd treatment. Overexpression of AemNAC2 in the wheat cultivar ‘Bobwhite’ led to reduce Cd concentration in the root, shoot and grains. AemNAC2 is an important TF that contributes to Cd tolerance in wheat.

中文翻译：

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来自 Aegilops markgrafii 的 NAC 转录因子降低了转基因小麦中的镉浓度

镉（Cd）是对人体健康危害最大的重金属元素之一，镉通过食物链的传播是一个全球性问题。Aegilops markgrafii 是栽培小麦的野生近缘种，可耐受高水平的 Cd。本研究的目的是调查参与 Ae 镉耐受性的 NAC 转录因子 (TF)。markgrafii 并验证它们在转基因小麦中的功能。我们从 Ae 克隆了 NAC TF。markgrafii 植物暴露于过量的 Cd 处理。使用 qRT-PCR 检查根和芽组织中 NAC TF 的表达谱。通过农杆菌介导的转化获得转基因小麦。最后，我们检测了过量 Cd 处理下转基因小麦中的 Cd 浓度。我们确定了三个 NAC TF 并将它们分为四个亚家族。序列比对表明 NAC TFs 具有保守的 N 端结构域，但具有不同的 C 端结构域。在过量镉处理下，NAC TF 的表达谱显示 AemNAC2 和 AemNAC3 的转录上调约 150 倍。AemNAC2 在小麦品种 'Bobwhite' 中的过表达导致根、芽和籽粒中 Cd 浓度降低。AemNAC2 是一种重要的 TF，有助于小麦的 Cd 耐受性。