Identification of an abscisic acid transporter by functional screening using the receptor complex as a sensor

Yuri Kanno, Atsushi Hanada, Yasutaka Chiba, Takanari Ichikawa, Miki Nakazawa, Minami Matsui, Tomokazu Koshiba, Yuji Kamiya, Mitsunori Seo

Research output: Contribution to journalArticlepeer-review

270 Citations (Scopus)

Abstract

Movement of the plant hormone abscisic acid (ABA) within plants has been documented; however, the molecular mechanisms that regulate ABA transport are not fully understood. By using a modified yeast two-hybrid system, we screened Arabidopsis cDNAs capable of inducing interactions between the ABA receptor PYR/PYL/ RCAR and PP2C protein phosphatase under low ABA concentrations. By using this approach, we identified four members of the NRT1/PTR family as candidates for ABA importers. Transport assays in yeast and insect cells demonstrated that at least one of the candidates ABA-IMPORTING TRANSPORTER (AIT) 1, which had been characterized as the low-affinity nitrate transporter NRT1.2, mediates cellular ABA uptake. Compared with WT, the ait1/nrt1.2 mutants were less sensitive to exogenously applied ABA during seed germination and/or postgermination growth, whereas overexpression of AIT1/NRT1.2 resulted in ABA hypersensitivity in the same conditions. Interestingly, the inflorescence stems of ait1/ nrt1.2 had a lower surface temperature than those of the WT because of excess water loss from open stomata. We detected promoter activities of AIT1/NRT1.2 around vascular tissues in inflorescence stems, leaves, and roots. These data suggest that the function of AIT1/NRT1.2 as an ABA importer at the site of ABA biosynthesis is important for the regulation of stomatal aperture in inflorescence stems.

Original languageEnglish
Pages (from-to)9653-9658
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume109
Issue number24
DOIs
Publication statusPublished - 12 Jun 2012
Externally publishedYes

Keywords

  • Guard cells
  • Liquid chromatography-tandem mass spectrometry
  • Water stress

Field of Science

  • 1.6 Biological sciences

Publication Type

  • 1.1. Scientific article indexed in Web of Science and/or Scopus database

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