BACKGROUND Plant ZIP genes represent an important transporter family involved in metal transport. Evidence has implied that some ZIPs may contribute to plant Cd uptake, but a genome-wide examination of ZIPs' role in Cd tolerance and uptake has rarely been reported. In this study, a genome-wide bioinformatic screening of candidate ZIP genes in Arabidopsis and rice was performed, followed by a systematic determination of their expression profile in response to Cd stress. Typical up-regulated ZIPs genes were then expressed in yeast cells to examine their effect on hosts' Cd uptake. RESULTS A total of 27 ZIP genes in Arabidopsis and rice were screened out based on sequence similarity. In Arabidopsis, Cd exposure strongly impacted the expression of most ZIPs, among which AtIRT1, AtIRT2, AtIRT4 AtZIP9, AtZIP10 and AtZIP12 were sharply up-regulated and AtIRT3, AtIRT5 were significantly down-regulated in root. In rice, all tested genes in shoot except for OsIRT1 and OsIRT12 were sharply up-regulated, while OsIRT1 and OsZIP1 in root were significantly down-regulated. Interestingly, some genes like AtIRT3, AtZIP5, AtZIP12, OsIRT1 and OsZIP1 showed converse expression regulation when subject to the tested Cd stress. When expressed in yeast cells, three ZIPs, AtIRT1, OsZIP1 and OsZIP3, caused a substantial increase in Cd sensitivity and Cd accumulation of the host cells. CONCLUSIONS In conclusion, this study revealed a distinct pattern in ZIPs family genes expression between Arabidopsis and rice in response to Cd stress. Arabidopsis mainly up-regulated root ZIPs genes, while rice mainly up-regulated shoot ZIPs genes. Three genes, AtIRT1, OsZIP1 and OsZIP3, conferred an increased Cd accumulation and sensitivity to Cd stress when expressed in yeast cells, further implying their roles in Cd uptake in plants.

中文翻译：

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拟南芥和水稻在响应Cd胁迫的ZIPs基因表达谱中显示出独特的模式。

背景技术植物ZIP基因代表参与金属运输的重要运输族。有证据表明，某些ZIP可能有助于植物吸收Cd，但是很少有基因组范围内检测ZIP在Cd耐受性和吸收中的作用。在这项研究中，对拟南芥和水稻中的候选ZIP基因进行了全基因组生物信息学筛选，然后系统地确定了它们对Cd胁迫的表达情况。然后在酵母细胞中表达典型的上调的ZIPS基因，以检查它们对宿主Cd吸收的影响。结果根据序列相似性，共筛选出拟南芥和水稻中的27个ZIP基因。在拟南芥中，Cd暴露强烈影响大多数ZIP的表达，其中包括AtIRT1，AtIRT2，AtIRT4，AtZIP9，根中，AtZIP10和AtZIP12急剧上调，而AtIRT3，AtIRT5明显下调。在水稻中，除了OsIRT1和OsIRT12外，所有受试基因均急剧上调，而根中的OsIRT1和OsZIP1则显着下调。有趣的是，一些基因如AtIRT3，AtZIP5，AtZIP12，OsIRT1和OsZIP1在受到Cd胁迫时表现出相反的表达调控。当在酵母细胞中表达时，三个ZIP，AtIRT1，OsZIP1和OsZIP3导致宿主细胞对Cd的敏感性和Cd的积累大大增加。结论总之，本研究揭示了响应Cd胁迫的拟南芥和水稻之间ZIPS家族基因表达的独特模式。拟南芥主要上调根ZIPs基因，而水稻主要上调芽ZIPs基因。AtIRT1这三个基因