Amino Acid Export in Plants： A Missing Link in Nitrogen Cycling

作     者：Sakiko Okumoto Guillaume Pilot 

作者机构：549 Latham Hall Virginia Tech Blacksburg VA 24061 USA 209 Latham Hall Virginia Tech Blacksburg VA 24061 USA 

出 版 物：《Molecular Plant》 (分子植物（英文版）)

年 卷 期：2011年第4卷第3期

页      面：453-463页

核心收录：

学科分类：0710[理学-生物学] 0832[工学-食品科学与工程（可授工学、农学学位）] 071010[理学-生物化学与分子生物学] 081704[工学-应用化学] 07[理学] 08[工学] 0817[工学-化学工程与技术] 083201[工学-食品科学] 

基　　金：美国国立卫生研究院(NIH)项目 Jeffress Memorial Trust 

主　　题：Nitrogen amino acids membrane transport. 

摘      要：The export of nutrients from source organs to parts of the body where they are required （e.g. sink organs） is a fundamental biological process. Export of amino acids, one of the most abundant nitrogen species in plant long-distance transport tissues （i.e. xylem and phloem）, is an essential process for the proper distribution of nitrogen in the plant. Phys- iological studies have detected the presence of multiple amino acid export systems in plant cell membranes. Yet, surpris- ingly little is known about the molecular identity of amino acid exporters, partially due to the technical difficulties hampering the identification of exporter proteins. In this short review, we will summarize our current knowledge about amino acid export systems in plants. Several studies have described plant amino acid transporters capable of bi-directional, facilitative transport, reminiscent of activities identified by earlier physiological studies. Moreover, recent expansion in the number of available amino acid transporter sequences have revealed evolutionary relationships between amino acid exporters from other organisms with a number of uncharacterized plant proteins, some of which might also function as amino acid exporters. In addition, genes that may regulate export of amino acids have been discovered. Studies of these putative transporter and regulator proteins may help in understanding the elusive molecular mechanisms of amino acid export in plants.