Golgi-Localized Cation/Proton Exchangers Regulate Ionic Homeostasis and Skotomorphogenesis in Arabidopsis.
Authors of this article are:
Wang Y Tang RJ Yang X Zheng X Shao Q Tang QL Fu A Luan S.
A summary of the article is shown below:
Multiple transporters and channels mediate cation transport across the plasma membrane and tonoplast to regulate ionic homeostasis in plant cells. However, much less is known about the molecular function of transporters that facilitate cation transport in other organelles such as Golgi. We report here that Arabidopsis KEA4, KEA5, and KEA6, members of cation/proton antiporters-2 (CPA2) superfamily were co-localized with the known Golgi marker, SYP32-mCherry. While single kea4,5,6 mutants showed similar phenotype as the wild type under various conditions, kea4/5/6 triple mutants showed hypersensitivity to low pH, high K+ , and high Na+ and displayed growth defects in darkness, suggesting that these three KEA-type transporters function redundantly in controlling etiolated seedling growth and ion homeostasis. Detailed analysis indicated that the kea4/5/6 triple mutant exhibited cell wall biosynthesis defect during the rapid etiolated seedling growth and under high K+ /Na+ condition. The cell-wall derived pectin homogalacturonan (GalA)3 partially suppressed the growth defects and ionic toxicity in the kea4/5/6 triple mutants when grown in the dark but not in the light conditions. Together, these data support the hypothesis that the Golgi-localized KEAs play key roles in the maintenance of ionic and pH homeostasis thereby facilitating Golgi function in cell wall biosynthesis during rapid etiolated seedling growth and in coping with high K+ /Na+ stress.
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This article is a good source of information and a good way to become familiar with topics such as: Cell wall biosynthesis;organelle transport;pH regulation;salinity tolerance.
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