9-cis-epoxycarotenoid dioxygenase

9-cis-epoxycarotenoid dioxygenase (EC 1.13.11.51, nine-cis-epoxycarotenoid dioxygenase, NCED, AtNCED3, PvNCED1, VP14) is an enzyme with systematic name 9-cis-epoxycarotenoid 11,12-dioxygenase.[1][2][3][4][5] This enzyme catalyses the following chemical reaction

(1) a 9-cis-epoxycarotenoid + O2 2-cis,4-trans-xanthoxin + a 12'-apo-carotenal
(2) 9-cis-violaxanthin + O2 2-cis,4-trans-xanthoxin + (3S,5R,6S)-5,6-epoxy-3-hydroxy-5,6-dihydro-12'-apo-beta-caroten-12'-al
(3) 9'-cis-neoxanthin + O2 2-cis,4-trans-xanthoxin + (3S,5R,6R)-5,6-dihydroxy-6,7-didehydro-5,6-dihydro-12'-apo-beta-caroten-12'-al
9-cis-epoxycarotenoid dioxygenase
Identifiers
EC number1.13.11.51
CAS number199877-10-6
Databases
IntEnzIntEnz view
BRENDABRENDA entry
ExPASyNiceZyme view
KEGGKEGG entry
MetaCycmetabolic pathway
PRIAMprofile
PDB structuresRCSB PDB PDBe PDBsum

9-cis-epoxycarotenoid dioxygenase contains iron(II).

Genomic sequence: Chromosome: 3; NC_003074.8 (4831286..4834015, complement)[6]

Gene function

Overexpression of the AtNCED3 gene improves the tolerance of transgenic plants to dehydration stress[5] as well as to salinity stress. Overexpression also leads to the overexpression of other genes induced by drought-stress. Transgenics containing AtNCED3 had greater root biomass, bigger pith size and higher level of photosynthesis.[7] It has been suggested that the AtNCED3 gene promoter contains G-box-like cis-acting elements which are responsible for dehydration-induced expression.[8]

Gene expression differs by plant organ. The gene may have a dual role in roots by either promoting or inhibiting the development of lateral roots.[9][10] AtNCED3 functions in seeds by regulating the seed establishment and abortion, maturation of the embryo, and seed dormancy. Maternal ABA functions in the early stage of zygote development, while embryonal AtNCED3 expresses later for ABA synthesis in case of dormancy. Expression of the gene mainly happens in the maternal tissues in the basal part of seeds or funiculus.[9]

AtNCED3 gene expression responds to drought-stress[11][5] and salt-stress.[12][7] The signal caused by low moisture in the air is first induced by the stomata of leaves and transferred to other cells and tissues, which upregulate the expression of the AtNCED3 gene and ABA synthesis. Stomata closure limits various processes, including air exchange, water loss and O2 release. The AtNCED3 gene is active and expressed under these circumstances.[11][5] Accumulation of AtNCED3 mRNA and AtNCED3 protein was first found in the vascular parenchyma cells under drought stress, which suggested that plant drought tolerance relates to the development of plant vascular tissue.[11] Also, overexpression of AtNCED3 gene can improve plant salt tolerance.

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References
  1. Schwartz SH, Tan BC, Gage DA, Zeevaart JA, McCarty DR (June 1997). "Specific oxidative cleavage of carotenoids by VP14 of maize". Science. 276 (5320): 1872–4. doi:10.1126/science.276.5320.1872. PMID 9188535.
  2. Tan BC, Schwartz SH, Zeevaart JA, McCarty DR (October 1997). "Genetic control of abscisic acid biosynthesis in maize". Proceedings of the National Academy of Sciences of the United States of America. 94 (22): 12235–40. doi:10.1073/pnas.94.22.12235. PMC 23760. PMID 9342392.
  3. Qin X, Zeevaart JA (December 1999). "The 9-cis-epoxycarotenoid cleavage reaction is the key regulatory step of abscisic acid biosynthesis in water-stressed bean". Proceedings of the National Academy of Sciences of the United States of America. 96 (26): 15354–61. doi:10.1073/pnas.96.26.15354. PMC 24823. PMID 10611388.
  4. Thompson AJ, Jackson AC, Symonds RC, Mulholland BJ, Dadswell AR, Blake PS, Burbidge A, Taylor IB (August 2000). "Ectopic expression of a tomato 9-cis-epoxycarotenoid dioxygenase gene causes over-production of abscisic acid". The Plant Journal. 23 (3): 363–74. doi:10.1046/j.1365-313x.2000.00789.x. PMID 10929129.
  5. Iuchi, S.; Kobayashi, M.; Taji, T.; Naramoto, M.; Seki, M.; Kato, T.; Tabata, S.; Kakubari, Y.; Yamaguchi-Shinozaki, K.; Shinozaki, K. (2002). "Regulation of drought tolerance by gene manipulation of 9-cis-epoxycarotenoid dioxygenase, a key enzyme in abscisic acid biosynthesis in Arabidopsis". Plant J. 30 (5): 611. doi:10.1046/j.1365-313X.2002.01347.x.
  6. John, Bernard; Lewis, Kenneth R. (1968), The Chromosome Complement, Springer Vienna, pp. 1–196, doi:10.1007/978-3-7091-5781-7_1, ISBN 9783211808818
  7. Lawson, S. S. and Michler, C. H. 2014. Overexpression of AtSTO1 leads to improved salt tolerance in populus tremula× P. alba. Transgenic Res. 23: 817-826.
  8. Behnam, B., Iuchi, S., Fujita, M., Fujita, Y., Takasaki, H., Osakabe, Y., Yamaguchi-Shinozaki, K., Kobayashi, M., Shinozaki, K. 2013. Characterization of the promoter region of an arabidopsis gene for 9-cis-epoxycarotenoid dioxygenase involved in dehydration-inducible transcription. DNA Res. 20: 315-324.
  9. Tan, B., Joseph, L. M., Deng, W., Liu, L., Li, Q., Cline, K., McCarty, D. R. 2003. Molecular characterization of the arabidopsis 9‐cis epoxycarotenoid dioxygenase gene family. The Plant Journal 35: 44-56.
  10. Sharp, R. E., Wu, Y., Voetberg, G. S., Saab, I. N., LeNoble, M. E. 1994. Confirmation that abscisic acid accumulation is required for maize primary root elongation at low water potentials. J. Exp. Bot. 45: 1743-1751.
  11. Endo, A., Sawada, Y., Takahashi, H., Okamoto, M., Ikegami, K., Koiwai, H., Seo, M., Toyomasu, T., Mitsuhashi, W., Shinozaki, K., Nakazono, M., Kamiya, Y., Koshiba, T., Nambara, E. 2008. Drought induction of arabidopsis 9-cis-epoxycarotenoid dioxygenase occurs in vascular parenchyma cells. Plant Physiol. 147: 1984-1993.
  12. Barrero, J., RodrÍGuez, P. L., Quesada, V., Piqueras, P., Ponce, M. R., Micol, J. L. 2006. Both abscisic acid (ABA)‐dependent and ABA‐independent pathways govern the induction of NCED3, AAO3 and ABA1 in response to salt stress. Plant, Cell Environ. 29: 2000-2008.
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