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Gene Review

NPQ1  -  Violaxanthin de-epoxidase

Arabidopsis thaliana

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Disease relevance of NPQ1

  • The corresponding increases in non-photochemical quenching and greater rates of non-stomatal water loss from these regions, as well as the partial reversal of low PhiPSII by increasing the ambient CO2 concentration, suggests that localized water stress and reduced stomatal conductance contributed to the inhibition of photosynthesis [1].

High impact information on NPQ1


Biological context of NPQ1

  • LHC II protein phosphorylation in leaves of Arabidopsis thaliana mutants deficient in non-photochemical quenching [4].
  • Lipid peroxidation was amplified markedly under chilling stress, and photooxidative damage ultimately resulted in leaf bleaching and tissue necrosis in npq1 [3].
  • At low light intensity, chlorophyll fluorescence induction kinetics is close to those found in wild type, but non-photochemical quenching strongly increases with increasing actinic light intensity resulting in steady state fluorescence levels of about 60% of the minimal dark fluorescence [5].
  • This was in contrast to the npq1 single mutant that showed only slight deviations from the wild-type phenotype under the conditions used [6].
  • Thermoluminescence measurements indicated that high photon flux densities (>500 micromol m(-2) s(-1)) promoted oxidative stress in the chloroplasts of npq1 ML, which was associated with a loss of chlorophyll and an inhibition of the photochemical activity [7].

Anatomical context of NPQ1

  • In the photoinhibition-sensitive Arabidopsis thaliana mutant NPQ1, a large but transient emission of (E)-2-hexenal was also observed a few minutes after the high-light treatment, indicating extensive damage to the membranes [8].
  • De-epoxidation from the opposite, stroma side of the membrane has been investigated in the npq1 mutant from Arabidopsis thaliana (L.) Heynh. - which lacks VxDE - by adding partially purified VxDE from spinach thylakoids [9].
  • In accordance with the function of two types of photoreceptors in photoinhibition, NPQ was found to offer only partial protection against photoinhibition at visible wavelengths [10].

Associations of NPQ1 with chemical compounds

  • The npq1 exhibited low antheraxanthin and zeaxanthin and high violaxanthin levels and the uncoupler-sensitive amplitudes of short (< 1 ns) PS II Chl a fluorescence distribution modes were strongly inhibited compared to the WT [11].
  • An npq1 lut2 double mutant was constructed, which lacks both zeaxanthin and lutein due to defects in the violaxanthin de-epoxidase and lycopene in-cyclase genes [12].
  • Despite the defects in xanthophyll composition and NPQ, the npq1 lut2 mutant exhibited a remarkable ability to tolerate high light [12].
  • Crosses between vtc2-2 and Arabidopsis ecotype Columbia established that the ascorbate deficiency cosegregated with the NPQ phenotype [13].
  • No such effects were seen in young leaves (YL) of npq1, which were quite tolerant to strong light and eosin-induced singlet oxygen [7].

Other interactions of NPQ1


Analytical, diagnostic and therapeutic context of NPQ1

  • Blue light-specific opening, probed by adding blue light (10 micromol m-2 s-1) to a 100 micromol m-2 s-1 red background, was found in WT, but not in npq1 or phot1 phot2 double mutant stomata [16].


  1. The differential effects of herbivory by first and fourth instars of Trichoplusia ni (Lepidoptera: Noctuidae) on photosynthesis in Arabidopsis thaliana. Tang, J.Y., Zielinski, R.E., Zangerl, A.R., Crofts, A.R., Berenbaum, M.R., Delucia, E.H. J. Exp. Bot. (2006) [Pubmed]
  2. Arabidopsis mutants define a central role for the xanthophyll cycle in the regulation of photosynthetic energy conversion. Niyogi, K.K., Grossman, A.R., Björkman, O. Plant Cell (1998) [Pubmed]
  3. The violaxanthin cycle protects plants from photooxidative damage by more than one mechanism. Havaux, M., Niyogi, K.K. Proc. Natl. Acad. Sci. U.S.A. (1999) [Pubmed]
  4. LHC II protein phosphorylation in leaves of Arabidopsis thaliana mutants deficient in non-photochemical quenching. Breitholtz, H.L., Srivastava, R., Tyystjärvi, E., Rintamäki, E. Photosyn. Res. (2005) [Pubmed]
  5. Inactivation of the chloroplast ATP synthase gamma subunit results in high non-photochemical fluorescence quenching and altered nuclear gene expression in Arabidopsis thaliana. Bosco, C.D., Lezhneva, L., Biehl, A., Leister, D., Strotmann, H., Wanner, G., Meurer, J. J. Biol. Chem. (2004) [Pubmed]
  6. Zeaxanthin deficiency enhances the high light sensitivity of an ascorbate-deficient mutant of Arabidopsis. Müller-Moulé, P., Havaux, M., Niyogi, K.K. Plant Physiol. (2003) [Pubmed]
  7. Photodamage of the photosynthetic apparatus and its dependence on the leaf developmental stage in the npq1 Arabidopsis mutant deficient in the xanthophyll cycle enzyme violaxanthin de-epoxidase. Havaux, M., Bonfils, J.P., Lütz, C., Niyogi, K.K. Plant Physiol. (2000) [Pubmed]
  8. On the induction of volatile organic compound emissions by plants as consequence of wounding or fluctuations of light and temperature. Loreto, F., Barta, C., Brilli, F., Nogues, I. Plant Cell Environ. (2006) [Pubmed]
  9. Comparison of violaxanthin de-epoxidation from the stroma and lumen sides of isolated thylakoid membranes from Arabidopsis: implications for the mechanism of de-epoxidation. Macko, S., Wehner, A., Jahns, P. Planta (2002) [Pubmed]
  10. Action Spectrum of Photoinhibition in Leaves of Wild Type and npq1-2 and npq4-1 Mutants of Arabidopsis thaliana. Sarvikas, P., Hakala, M., Pätsikkä, E., Tyystjärvi, T., Tyystjärvi, E. Plant Cell Physiol. (2006) [Pubmed]
  11. Xanthophyll cycle-dependent nonphotochemical quenching in Photosystem II: Mechanistic insights gained from Arabidopsis thaliana L. mutants that lack violaxanthin deepoxidase activity and/or lutein. Gilmore, A.M. Photosyn. Res. (2001) [Pubmed]
  12. Photoprotection in a zeaxanthin- and lutein-deficient double mutant of Arabidopsis. Niyogi, K.K., Shih, C., Soon Chow, W., Pogson, B.J., Dellapenna, D., Björkman, O. Photosyn. Res. (2001) [Pubmed]
  13. Ascorbate deficiency can limit violaxanthin de-epoxidase activity in vivo. Müller-Moulé, P., Conklin, P.L., Niyogi, K.K. Plant Physiol. (2002) [Pubmed]
  14. Cytochrome b(6)f mutation specifically affects thermal dissipation of absorbed light energy in Arabidopsis. Munekage, Y., Takeda, S., Endo, T., Jahns, P., Hashimoto, T., Shikanai, T. Plant J. (2001) [Pubmed]
  15. Arabidopsis thaliana plants lacking the PSI-D subunit of photosystem I suffer severe photoinhibition, have unstable photosystem I complexes, and altered redox homeostasis in the chloroplast stroma. Haldrup, A., Lunde, C., Scheller, H.V. J. Biol. Chem. (2003) [Pubmed]
  16. Blue light and phytochrome-mediated stomatal opening in the npq1 and phot1 phot2 mutants of Arabidopsis. Talbott, L.D., Shmayevich, I.J., Chung, Y., Hammad, J.W., Zeiger, E. Plant Physiol. (2003) [Pubmed]
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