A T-DNA insertion mutant of AtHMA1 gene encoding a Cu transporting ATPase in Arabidopsis thaliana has a defect in the water-water cycle of photosynthesis

Mieko Higuchi, Hiroshi Ozaki, Minami Matsui, Kintake Sonoike

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12 Citations (Scopus)

Abstract

The water-water cycle is the electron flow through scavenging enzymes for the reactive species of oxygen in chloroplasts, and is proposed to play a role in alternative electron sink in photosynthesis. Here we showed that the water-water cycle is impaired in the T-DNA insertion mutant of AtHMA1 gene encoding a Cu transporting ATPase in chloroplasts. Chlorophyll fluorescence under steady state was not affected in hma1, indicating that photosynthetic electron transport under normal condition was not impaired. Under electron acceptor limited conditions, however, hma1 showed distinguished phenotype in chlorophyll fluorescence characteristics. The most severe phenotype of hma1 could be observed in high (0.1%) CO2 concentrations, indicating that hma1 has the defect other than photorespiration. The transient increase of chlorophyll fluorescence upon the cessation of the actinic light as well as the NPQ induction of chlorophyll fluorescence revealed that the two pathways of cyclic electron flow around PSI, NDH-pathway and FQR-pathway, are both intact in hma1. Based on the NPQ induction under 0% oxygen condition, we conclude that the water-water cycle is impaired in hma1, presumably due to the decreased level of Cu/Zn SOD in the mutant. Under high CO2 condition, hma1 exhibited slightly higher NPQ induction than wild type plants, while this increase of NPQ in hma1 was suppressed when hma1 was crossed with crr2 having a defect in NDH-mediated PSI cyclic electron flow. We propose that the water-water cycle and NDH-mediated pathways might be regulated compensationally with each other especially when photorespiration is suppressed.

Original languageEnglish
Pages (from-to)205-213
Number of pages9
JournalJournal of Photochemistry and Photobiology B: Biology
Volume94
Issue number3
DOIs
Publication statusPublished - 2009 Mar 3
Externally publishedYes

Fingerprint

Water Cycle
hydrological cycle
photosynthesis
Photosynthesis
Arabidopsis
genes
Adenosine Triphosphatases
insertion
Chlorophyll
coding
deoxyribonucleic acid
chlorophylls
Electrons
Fluorescence
Water
defects
water
chloroplasts
Genes
fluorescence

Keywords

  • Arabidopsis thaliana
  • AtHMA1
  • Cu transporting ATPase in chloroplast
  • Cu/Zn SOD
  • Cyclic electron flow around PSI
  • Water-water cycle

ASJC Scopus subject areas

  • Radiation
  • Radiology Nuclear Medicine and imaging
  • Radiological and Ultrasound Technology
  • Biophysics

Cite this

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title = "A T-DNA insertion mutant of AtHMA1 gene encoding a Cu transporting ATPase in Arabidopsis thaliana has a defect in the water-water cycle of photosynthesis",
abstract = "The water-water cycle is the electron flow through scavenging enzymes for the reactive species of oxygen in chloroplasts, and is proposed to play a role in alternative electron sink in photosynthesis. Here we showed that the water-water cycle is impaired in the T-DNA insertion mutant of AtHMA1 gene encoding a Cu transporting ATPase in chloroplasts. Chlorophyll fluorescence under steady state was not affected in hma1, indicating that photosynthetic electron transport under normal condition was not impaired. Under electron acceptor limited conditions, however, hma1 showed distinguished phenotype in chlorophyll fluorescence characteristics. The most severe phenotype of hma1 could be observed in high (0.1{\%}) CO2 concentrations, indicating that hma1 has the defect other than photorespiration. The transient increase of chlorophyll fluorescence upon the cessation of the actinic light as well as the NPQ induction of chlorophyll fluorescence revealed that the two pathways of cyclic electron flow around PSI, NDH-pathway and FQR-pathway, are both intact in hma1. Based on the NPQ induction under 0{\%} oxygen condition, we conclude that the water-water cycle is impaired in hma1, presumably due to the decreased level of Cu/Zn SOD in the mutant. Under high CO2 condition, hma1 exhibited slightly higher NPQ induction than wild type plants, while this increase of NPQ in hma1 was suppressed when hma1 was crossed with crr2 having a defect in NDH-mediated PSI cyclic electron flow. We propose that the water-water cycle and NDH-mediated pathways might be regulated compensationally with each other especially when photorespiration is suppressed.",
keywords = "Arabidopsis thaliana, AtHMA1, Cu transporting ATPase in chloroplast, Cu/Zn SOD, Cyclic electron flow around PSI, Water-water cycle",
author = "Mieko Higuchi and Hiroshi Ozaki and Minami Matsui and Kintake Sonoike",
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T1 - A T-DNA insertion mutant of AtHMA1 gene encoding a Cu transporting ATPase in Arabidopsis thaliana has a defect in the water-water cycle of photosynthesis

AU - Higuchi, Mieko

AU - Ozaki, Hiroshi

AU - Matsui, Minami

AU - Sonoike, Kintake

PY - 2009/3/3

Y1 - 2009/3/3

N2 - The water-water cycle is the electron flow through scavenging enzymes for the reactive species of oxygen in chloroplasts, and is proposed to play a role in alternative electron sink in photosynthesis. Here we showed that the water-water cycle is impaired in the T-DNA insertion mutant of AtHMA1 gene encoding a Cu transporting ATPase in chloroplasts. Chlorophyll fluorescence under steady state was not affected in hma1, indicating that photosynthetic electron transport under normal condition was not impaired. Under electron acceptor limited conditions, however, hma1 showed distinguished phenotype in chlorophyll fluorescence characteristics. The most severe phenotype of hma1 could be observed in high (0.1%) CO2 concentrations, indicating that hma1 has the defect other than photorespiration. The transient increase of chlorophyll fluorescence upon the cessation of the actinic light as well as the NPQ induction of chlorophyll fluorescence revealed that the two pathways of cyclic electron flow around PSI, NDH-pathway and FQR-pathway, are both intact in hma1. Based on the NPQ induction under 0% oxygen condition, we conclude that the water-water cycle is impaired in hma1, presumably due to the decreased level of Cu/Zn SOD in the mutant. Under high CO2 condition, hma1 exhibited slightly higher NPQ induction than wild type plants, while this increase of NPQ in hma1 was suppressed when hma1 was crossed with crr2 having a defect in NDH-mediated PSI cyclic electron flow. We propose that the water-water cycle and NDH-mediated pathways might be regulated compensationally with each other especially when photorespiration is suppressed.

AB - The water-water cycle is the electron flow through scavenging enzymes for the reactive species of oxygen in chloroplasts, and is proposed to play a role in alternative electron sink in photosynthesis. Here we showed that the water-water cycle is impaired in the T-DNA insertion mutant of AtHMA1 gene encoding a Cu transporting ATPase in chloroplasts. Chlorophyll fluorescence under steady state was not affected in hma1, indicating that photosynthetic electron transport under normal condition was not impaired. Under electron acceptor limited conditions, however, hma1 showed distinguished phenotype in chlorophyll fluorescence characteristics. The most severe phenotype of hma1 could be observed in high (0.1%) CO2 concentrations, indicating that hma1 has the defect other than photorespiration. The transient increase of chlorophyll fluorescence upon the cessation of the actinic light as well as the NPQ induction of chlorophyll fluorescence revealed that the two pathways of cyclic electron flow around PSI, NDH-pathway and FQR-pathway, are both intact in hma1. Based on the NPQ induction under 0% oxygen condition, we conclude that the water-water cycle is impaired in hma1, presumably due to the decreased level of Cu/Zn SOD in the mutant. Under high CO2 condition, hma1 exhibited slightly higher NPQ induction than wild type plants, while this increase of NPQ in hma1 was suppressed when hma1 was crossed with crr2 having a defect in NDH-mediated PSI cyclic electron flow. We propose that the water-water cycle and NDH-mediated pathways might be regulated compensationally with each other especially when photorespiration is suppressed.

KW - Arabidopsis thaliana

KW - AtHMA1

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KW - Cyclic electron flow around PSI

KW - Water-water cycle

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M3 - Article

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EP - 213

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JF - Journal of Photochemistry and Photobiology B: Biology

SN - 1011-1344

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