Os03g0645900

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OsNCED3 is a monocot rice NCED gene[1][2].

Annotated Information

Function

  • OsNCED3 is functionally active in dicot Arabidopsis plants since the ectopic expression of OsNCED3 successfully complements the 129B08/nced3 mutant phenotype[1].
  • In addition to ABA biosynthesis, the monocot OsNCED3 gene may have additional functions in shaping leaf morphology and vascular bundle development in Arabidopsis[1].
  • OsNCED3 promoter is stress-inducible in a whole rice plant except for in the aleurones and endosperm and stably active over three generations[2].

Mutation

  • Seed ABA content and germination patterns are similar between wild-type and the 129B08/nced3 mutant, suggesting functional redundancy or differential spatial expression of other NCED gene family members[1].
  • Transgenic Arabidopsis lines overexpressing the monocot OsNCED3 gene in a wild-type background result in a smaller and rounder leaf shape and midvein[1].
  • The OsNCED3:gfp transgenic plants of T2 generations[2]:
    • The transgene copy numbers in the lines harboring the OsNCED3:gfp construct were determined and six single- and two double-copy transgenic lines were analyzed for promoter activity in comparison with the Wsi18[3], a stress-inducible promoter previously characterized.
    • The highest induction levels of gfp transcripts in the OsNCED3:gfp plants upon drought treatments were 161- and 93-fold in leaves and roots, respectively, and these levels were comparable with those of gfp transcripts in the Wsi18:gfp plants.
    • A comparison of the promoter activities between the T2–T4 plants revealed that comparable activity levels were maintained over these three homozygous generations with no evidence of silencing.

Expression

  • Overexpression of OsNCED3 in wild-type Arabidopsis plants results in increased accumulation of ABA, reduced relative water loss, delayed seed germination, and greater drought tolerance relative to that of wild-type[1].
  • Foldinduction levels of OsNCED3 was much higher than that of Wsi18[3], a drought-inducible gene previously characterized[2][3]. OsNCED3 promoter activity levels are markedly enhanced by drought conditions in various tissues and at different growth stages in rice plants.
  • The transcript levels of OsNCED3 were largely increased under drought conditions in all tissues except for dry seeds and flowers. OsNCED3 promoter is significantly activated in the roots and leaves by drought conditions but not in the grains or flowers where only zero to low levels of fluorescence could be detected[2].
  • The OsNCED3 was significantly higher in the endosperm of plant #6095 than in the endosperm of Koshihikari. The level of expression of OsNCED3 was significantly higher in #6095 than in Koshihikari[4].
  • Marzougui et al. speculated that the reduced germination rate of #6095 at 4 and also 5 WAH may have resulted from the accumulation of OsNCED3 and ABA predicted from hyperaccumulation detected on SL502 at 4 WAH[4].

Knowledge Extension

  • The regulation of abscisic acid (ABA) biosynthesis is essential for plant responses to drought stress. A key regulated step in abscisic acid (ABA) biosynthesis in plants is catalyzed by 9-cis epoxycarotenoid dioxygenase (NCED), which cleaves 9-cis xanthophylls to xanthoxin, a precursor of ABA[5].
  • In Arabidopsis, ABA biosynthesis is controlled by a small family of NCED genes. Nine carotenoid cleavage dioxygenase (CCD) genes have been identified in the complete genome sequence. Differential membrane-binding capacity of AtNCEDs is a potential means of post-translational regulation of NCED activity[5].

Labs working on this gene

  • Institute of Plant and Microbial Biology, Academia Sinica, 128, Sect 2, Academia Rd, Nankang, Taipei 115, Taiwan, ROC
  • Department of Horticulture, National Taiwan University, Taipei, Taiwan, ROC
  • School of Biotechnology and Environmental Engineering, Myongji University, Yongin 449-728, Korea
  • National Academy of Agricultural Science, RDA, Suwon 441-707, Korea

References

  1. 1.0 1.1 1.2 1.3 1.4 1.5 Hwang S G, Chen H C, Huang W Y, et al. Ectopic expression of rice OsNCED3 in Arabidopsis increases ABA level and alters leaf morphology[J]. Plant science, 2010, 178(1): 12-22.
  2. 2.0 2.1 2.2 2.3 2.4 Bang S W, Park S H, Jeong J S, et al. Characterization of the stress-inducible OsNCED3 promoter in different transgenic rice organs and over three homozygous generations[J]. Planta, 2013, 237(1): 211-224.
  3. 3.0 3.1 3.2 Yi N, Oh S J, Kim Y S, et al. Analysis of the Wsi18, a stress-inducible promoter that is active in the whole grain of transgenic rice[J]. Transgenic research, 2011, 20(1): 153-163.
  4. 4.0 4.1 Marzougui S, Sugimoto K, Yamanouchi U, et al. Mapping and characterization of seed dormancy QTLs using chromosome segment substitution lines in rice[J]. Theoretical and Applied Genetics, 2012, 124(5): 893-902.
  5. 5.0 5.1 Tan B C, Joseph L M, Deng W T, et al. Molecular characterization of the Arabidopsis 9‐cis epoxycarotenoid dioxygenase gene family[J]. The Plant Journal, 2003, 35(1): 44-56.

Structured Information