AtCAT6, a sink-tissue-localized transporter for essential amino acids in Arabidopsis
AtCAT6, a sink-tissue-localized transporter for essential amino acids in Arabidopsis
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DOI：
10.1111/j.1365-313x.2006.02880.x
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发表时间：
2006-11-01
期刊：
影响因子：
7.2
通讯作者：
Schachtman, Daniel P.
中科院分区：
文献类型：
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作者：
Hammes, Ulrich Z.;Nielsen, Erik;Schachtman, Daniel P.
氨基酸代表了在植物中运输的还原态氮的主要形式。植物中的氨基酸转运蛋白通常表现出组织特异性表达模式，并且在发育期间和在变化的环境条件下被植物用于将这些代谢物从源转运到库。我们确定了一个氨基酸转运蛋白，AtCAT 6，这是表达在库组织，如侧根原基，花和种子。此外，AtCAT 6诱导的植物寄生的根结线虫，南方根结线虫侵染的根。定量逆转录酶PCR显示线虫诱导整个线虫侵染的持续时间和线虫诱导的摄食场所。启动子分析证实了内源性库组织和线虫诱导的摄食位点的表达。在非洲爪蟾卵母细胞中，AtCAT 6介导的蛋白质和非蛋白质氨基酸的产电运输具有中等亲和力。AtCAT 6运输大的，中性和阳离子氨基酸优先于其他氨基酸。该转运蛋白的敲除突变体不能在含有L-谷氨酰胺作为唯一氮源的培养基上生长。我们的数据表明，AtCAT 6在供应氨基酸的植物和线虫诱导的摄食结构的水槽组织中发挥作用。
Amino acids represent the major form of reduced nitrogen that is transported in plants. Amino acid transporters in plants often show tissue-specific expression patterns and are used by plants to transport these metabolites from source to sink during development and under changing environmental conditions. We identified one amino acid transporter, AtCAT6, which is expressed in sink tissues such as lateral root primordia, flowers and seeds. Additionally AtCAT6 was induced during infestation of roots by the plant-parasitic root-knot nematode, Meloidogyne incognita. Quantitative reverse-transcriptase PCR revealed nematode inducibility throughout the duration of nematode infestation and in nematode-induced feeding sites. Promoter analyses confirmed expression in endogenous sink tissues and nematode-induced feeding sites. In Xenopus oocytes, AtCAT6 mediated electrogenic transport of proteinogenic as well as non-proteinogenic amino acids with moderate affinity. AtCAT6 transported large, neutral and cationic amino acids in preference to other amino acids. Knockout mutants of this transporter failed to grow on medium containing L-glutamine as the sole nitrogen source. Our data suggest that AtCAT6 plays a role in supplying amino acids to sink tissues of plants and nematode-induced feeding structures.