Diverse Functions and Molecular Properties Emerging for CAX Cation/H+ Exchangers in Plants

Authors

  • T. Shigaki,

    Corresponding author
    1. USDA/ARS Children's Nutrition Research Center, Baylor College of Medicine, 1100 Bates St., Houston, TX 77030, USA
      USDA/ARS Children's Nutrition Research Center Baylor College of Medicine 1100 Bates St., Room 9016 Houston, TX 77030 USA E-mail: tshigaki@bcm.tmc.edu
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  • K. D. Hirschi

    1. USDA/ARS Children's Nutrition Research Center, Baylor College of Medicine, 1100 Bates St., Houston, TX 77030, USA
    2. Vegetable and Fruit Improvement Center, Texas A & M University, College Station, TX 77845, USA
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USDA/ARS Children's Nutrition Research Center Baylor College of Medicine 1100 Bates St., Room 9016 Houston, TX 77030 USA E-mail: tshigaki@bcm.tmc.edu

Abstract

Abstract: Steep concentration gradients of many ions are actively maintained, with lower concentrations typically located in the cytosol, and higher concentrations in organelles and outside the cell. The vacuole is an important storage organelle for many ions. The concentration gradient of cations is established across the plant tonoplast, in part, by high-capacity cation/H+ (CAX) exchange activity. While plants may not be green yeast, analysis of CAX regulation and substrate specificity has been greatly aided by utilizing yeast as an experimental tool. The basic CAX biology in Arabidopsis has immediate relevance toward understanding the functional interplay between diverse transport processes. The long-range applied goals are to identify novel transporters and express them in crop plants in order to “mine” nutrients out of the soil and into plants. In doing so, this could boost the levels of essential nutrients in plants.

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