Santa-María G E, Rubio F, Dubcovsky J, Rodríguez-Navarro A
Departamento de Biotecnología, Escuela Técnica Superior de Ingenieros Agrónomos, Madrid, Spain.
Plant Cell. 1997 Dec;9(12):2281-9. doi: 10.1105/tpc.9.12.2281.
The high-affinity K+ uptake system of plants plays a crucial role in nutrition and has been the subject of extensive kinetic studies. However, major components of this system remain to be identified. We isolated a cDNA from barley roots, HvHAK1, whose translated sequence shows homology to the Escherichia coli Kup and Schwanniomyces occidentalis HAK1 K+ transporters. HvHAK1 conferred high-affinity K+ uptake to a K(+)-uptake-deficient yeast mutant exhibiting the hallmark characteristics of the high-affinity K+ uptake described for barley roots. HvHAK1 also mediated low-affinity Na+ uptake. Another cDNA (HvHAK2) encoding a polypeptide 42% identical to HvHAK1 was also isolated. Analysis of several genomes of Triticeae indicates that HvHAK1 belongs to a multigene family. Translated sequences from bacterial DNAs and Arabidopsis, rice, and possibly human cDNAs show homology to the Kup-HAK1-HvHAK1 family of K+ transporters.
植物的高亲和性钾离子吸收系统在营养方面起着关键作用，一直是广泛动力学研究的主题。然而，该系统的主要成分仍有待确定。我们从大麦根中分离出一个cDNA，即HvHAK1，其翻译后的序列与大肠杆菌Kup和西方许旺酵母HAK1钾离子转运体具有同源性。HvHAK1赋予了一个钾离子吸收缺陷型酵母突变体高亲和性钾离子吸收能力，该突变体表现出大麦根中描述的高亲和性钾离子吸收的标志性特征。HvHAK1还介导低亲和性钠离子吸收。我们还分离出了另一个cDNA（HvHAK2），其编码的多肽与HvHAK1有42%的同一性。对几种小麦族基因组的分析表明，HvHAK1属于一个多基因家族。细菌DNA、拟南芥、水稻以及可能的人类cDNA的翻译序列与Kup-HAK1-HvHAK1钾离子转运体家族具有同源性。
