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| Subject Categories: Membranes & Transport | Plant Biology |
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| The EMBO Journal
(2007) 26, 3003–3014, doi:10.1038/sj.emboj.7601732 Published online 31 May 2007 |
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| Rice OsHKT2;1 transporter mediates large Na+ influx component into K+-starved roots for growth |
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| Tomoaki Horie1, Alex Costa1, Tae Houn Kim1, Min Jung Han2, Rie Horie1, Ho-Yin Leung1, Akio Miyao3, Hirohiko Hirochika3, Gynheung An2 and Julian I Schroeder1 |
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1 Division of Biological Sciences, Cell and Developmental Biology Section, and Center for Molecular Genetics, University of California, San Diego, La Jolla, CA, USA 2 National Research Laboratory of Plant Functional Genomics, Department of Life Science, Pohang University of Science and Technology, Kyungbuk, Republic of Korea 3 Division of Genome and Biodiversity Research, National Institute of Agrobiological Sciences, Ibaraki, Japan To whom correspondence should be addressed Julian I Schroeder, Division of Biological Sciences, Cell and Developmental Biology Section, and Center for Molecular Genetics, Room 5214, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0116, USA. Tel.: +1 858 534 7759; Fax: +1 858 534 7108; E-mail: julian@biomail.ucsd.edu Received 12 December 2006; Accepted 2 May 2007; Published online 31 May 2007. |
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| Abstract |
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| Excessive accumulation of sodium in plants causes toxicity. No mutation that greatly diminishes sodium (Na+) influx into plant roots has been isolated. The OsHKT2;1 (previously named OsHKT1) transporter from rice functions as a relatively Na+-selective transporter in heterologous expression systems, but the in vivo function of OsHKT2;1 remains unknown. Here, we analyzed transposon-insertion rice lines disrupted in OsHKT2;1. Interestingly, three independent oshkt2;1-null alleles exhibited significantly reduced growth compared with wild-type plants under low Na+ and K+ starvation conditions. The mutant alleles accumulated less Na+, but not less K+, in roots and shoots. OsHKT2;1 was mainly expressed in the cortex and endodermis of roots. 22Na+ tracer influx experiments revealed that Na+ influx into oshkt2;1-null roots was dramatically reduced compared with wild-type plants. A rapid repression of OsHKT2;1-mediated Na+ influx and mRNA reduction were found when wild-type plants were exposed to 30 mM NaCl. These analyses demonstrate that Na+ can enhance growth of rice under K+ starvation conditions, and that OsHKT2;1 is the central transporter for nutritional Na+ uptake into K+-starved rice roots. |
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| Keywords: HKT, Na+ uptake, salt stress |
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Top of page MORE ARTICLES LIKE THISThese links to content published by NPG are automatically generated RESEARCHRice OsHKT2;1 transporter mediates large Na + influx component into K + -starved roots for growth The EMBO Journal Article The EMBO Journal Article (01 May 2003) The EMBO Journal Article (01 May 2003) |
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