Homeostasis of microelements in organisms is vital for normal metabolism. In plants, the cation diffusion facilitator (CDF) protein family, also known as metal tolerance proteins (MTPs), play critical roles in maintaining trace metal homeostasis. However, little is known about these proteins in wheat. In this study, we characterized the MTP family of Triticum urartu, the donor of 'A' genome of Triticum aestivum, and analysed their phylogenetic relationships, sequence signatures, spatial expression patterns in the diploid wheat, and their transport activity when heterologously expressed. Nine MTPs were identified in the T. urartu genome database, and were classified and designated based on their sequence similarity to Arabidopsis thaliana (Arabidopsis) and Oryza sativa MTPs. Phylogenetic and sequence analyses indicated that the triticum urartu metal tolerance protein (TuMTP)s comprise three Zn-CDFs, two Fe/Zn-CDFs, and four Mn-CDFs; and can be further classified into six subgroups. Among the TuMTPs, there are no MTP2-5 and MTP9-10 counterparts but two MTP1/8/11 orthologs in relation to AtMTPs. It was also shown that members of the same cluster share similar sequence characteristic, i.e. number of introns, predicted transmembrane domains, and motifs. When expressed in yeast, TuMTP1 and TuMTP1.1 conferred tolerance to Zn and Co but not to other metal ions; while TuMTP8, TuMTP8.1, TuMTP11, and TuMTP11.1 conferred tolerance to Mn. When expressed in Arabidopsis, TuMTP1 localized to the tonoplast and significantly enhanced Zn and Co tolerance. TuMTPs showed diverse tissue-specific expression patterns. Taken together, the closely clustered TuMTPs share structural features and metal specificity but play diverse roles in the homeostasis of microelements in plant cells.

中文翻译：

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Triticum urartu 中编码金属耐受蛋白的基因家族的特征：系统发育、转录和功能分析。

生物体内微量元素的稳态对于正常新陈代谢至关重要。在植物中，阳离子扩散促进剂 (CDF) 蛋白家族，也称为金属耐受蛋白 (MTP)，在维持微量金属稳态方面发挥着关键作用。然而，人们对小麦中的这些蛋白质知之甚少。在这项研究中，我们表征了小麦 (Triticum aestivum) 'A' 基因组的供体 Triticum urartu 的 MTP 家族，并分析了它们在二倍体小麦中的系统发育关系、序列特征、空间表达模式以及它们在异源表达时的转运活性。在 T. urartu 基因组数据库中鉴定了九个 MTP，并根据它们与拟南芥 (Arabidopsis) 和 Oryza sativa MTP 的序列相似性进行分类和指定。系统发育和序列分析表明，黑小麦金属耐受蛋白（TuMTP）由3个Zn-CDF、2个Fe/Zn-CDF和4个Mn-CDF组成；并且可以进一步分为六个子组。在 TuMTP 中，没有 MTP2-5 和 MTP9-10 对应物，但有两个与 AtMTP 相关的 MTP1/8/11 直系同源物。还表明同一簇的成员具有相似的序列特征，即内含子数量、预测的跨膜结构域和基序。当在酵母中表达时，TuMTP1 和 TuMTP1.1 赋予对 Zn 和 Co 的耐受性，但不赋予对其他金属离子的耐受性；而 TuMTP8、TuMTP8.1、TuMTP11 和 TuMTP11.1 赋予了对 Mn 的耐受性。当在拟南芥中表达时，TuMTP1 定位于液泡膜并显着增强对锌和钴的耐受性。TuMTPs 显示出不同的组织特异性表达模式。综合起来，