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Overexpression of an ABA biosynthesis gene using a stress-inducible promoter enhances drought resistance in petunia.

Estrada-Melo AC - Hortic Res (2015)

Bottom Line: The response of plants to drought stress includes reduced transpiration as stomates close in response to increased abscisic acid (ABA) concentrations.Constitutive overexpression of 9-cis-epoxycarotenoid dioxygenase (NCED), a key enzyme in ABA biosynthesis, increases drought resistance, but causes negative pleiotropic effects on plant growth and development.Well-watered transgenic plants grew like non-transformed control plants and there was no effect of the transgene on seed dormancy.

View Article: PubMed Central - PubMed

Affiliation: Department of Plant Sciences, University of California Davis , Davis, CA, USA.

ABSTRACT
The response of plants to drought stress includes reduced transpiration as stomates close in response to increased abscisic acid (ABA) concentrations. Constitutive overexpression of 9-cis-epoxycarotenoid dioxygenase (NCED), a key enzyme in ABA biosynthesis, increases drought resistance, but causes negative pleiotropic effects on plant growth and development. We overexpressed the tomato NCED (LeNCED1) in petunia plants under the control of a stress-inducible promoter, rd29A. Under water stress, the transgenic plants had increased transcripts of NCED mRNA, elevated leaf ABA concentrations, increased concentrations of proline, and a significant increase in drought resistance. The transgenic plants also displayed the expected decreases in stomatal conductance, transpiration, and photosynthesis. After 14 days without water, the control plants were dead, but the transgenic plants, though wilted, recovered fully when re-watered. Well-watered transgenic plants grew like non-transformed control plants and there was no effect of the transgene on seed dormancy.

No MeSH data available.


Related in: MedlinePlus

Phenotypes of LeNCED-overexpressed petunia. The seedlings from non-transformed control, transgenic rd29A:LeNCED1 lines 8F, 7D, 3D, and CaMV-35S:LeNCED1-12F were grown in UC Mix soil in greenhouse. Daily irrigations were provided to maintain optimal non-stress growth conditions. Photographs were taken at different stages of development (4, 7, 10, and 13 weeks after sowing).
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fig1: Phenotypes of LeNCED-overexpressed petunia. The seedlings from non-transformed control, transgenic rd29A:LeNCED1 lines 8F, 7D, 3D, and CaMV-35S:LeNCED1-12F were grown in UC Mix soil in greenhouse. Daily irrigations were provided to maintain optimal non-stress growth conditions. Photographs were taken at different stages of development (4, 7, 10, and 13 weeks after sowing).

Mentions: Following self-pollination and kanamycin selection of 12 T0 lines obtained from the transformation facility, we selected three homozygous T2 transgenic rd29A:LeNCED1 lines 8F, 7D, and 3D. These plants exhibited normal growth and development under non-stress growth conditions (Figure 1). Anatomically, too, the plants were indistinguishable; we found no significant differences in stomatal density or stomatal index on abaxial and adaxial leaf surfaces between the transgenic rd29A:LeNCED1 and control plants (data not shown). T3 seedlings of these lines were used for further experiments. One homozygous line CaMV-35S:LeNCED1-12F, was used as a constitutive expression control in limited experiments. Under non-stressed conditions, the seeds from CaMV-35S:LeNCED1 plants showed low germination rate and the plants grew more slowly than the non-transformed control and rd29A:LeNCED1 plants (Figure 1), and older plants developed a severe photobleaching phenotype (Supplementary Figure 4).


Overexpression of an ABA biosynthesis gene using a stress-inducible promoter enhances drought resistance in petunia.

Estrada-Melo AC - Hortic Res (2015)

Phenotypes of LeNCED-overexpressed petunia. The seedlings from non-transformed control, transgenic rd29A:LeNCED1 lines 8F, 7D, 3D, and CaMV-35S:LeNCED1-12F were grown in UC Mix soil in greenhouse. Daily irrigations were provided to maintain optimal non-stress growth conditions. Photographs were taken at different stages of development (4, 7, 10, and 13 weeks after sowing).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4595983&req=5

fig1: Phenotypes of LeNCED-overexpressed petunia. The seedlings from non-transformed control, transgenic rd29A:LeNCED1 lines 8F, 7D, 3D, and CaMV-35S:LeNCED1-12F were grown in UC Mix soil in greenhouse. Daily irrigations were provided to maintain optimal non-stress growth conditions. Photographs were taken at different stages of development (4, 7, 10, and 13 weeks after sowing).
Mentions: Following self-pollination and kanamycin selection of 12 T0 lines obtained from the transformation facility, we selected three homozygous T2 transgenic rd29A:LeNCED1 lines 8F, 7D, and 3D. These plants exhibited normal growth and development under non-stress growth conditions (Figure 1). Anatomically, too, the plants were indistinguishable; we found no significant differences in stomatal density or stomatal index on abaxial and adaxial leaf surfaces between the transgenic rd29A:LeNCED1 and control plants (data not shown). T3 seedlings of these lines were used for further experiments. One homozygous line CaMV-35S:LeNCED1-12F, was used as a constitutive expression control in limited experiments. Under non-stressed conditions, the seeds from CaMV-35S:LeNCED1 plants showed low germination rate and the plants grew more slowly than the non-transformed control and rd29A:LeNCED1 plants (Figure 1), and older plants developed a severe photobleaching phenotype (Supplementary Figure 4).

Bottom Line: The response of plants to drought stress includes reduced transpiration as stomates close in response to increased abscisic acid (ABA) concentrations.Constitutive overexpression of 9-cis-epoxycarotenoid dioxygenase (NCED), a key enzyme in ABA biosynthesis, increases drought resistance, but causes negative pleiotropic effects on plant growth and development.Well-watered transgenic plants grew like non-transformed control plants and there was no effect of the transgene on seed dormancy.

View Article: PubMed Central - PubMed

Affiliation: Department of Plant Sciences, University of California Davis , Davis, CA, USA.

ABSTRACT
The response of plants to drought stress includes reduced transpiration as stomates close in response to increased abscisic acid (ABA) concentrations. Constitutive overexpression of 9-cis-epoxycarotenoid dioxygenase (NCED), a key enzyme in ABA biosynthesis, increases drought resistance, but causes negative pleiotropic effects on plant growth and development. We overexpressed the tomato NCED (LeNCED1) in petunia plants under the control of a stress-inducible promoter, rd29A. Under water stress, the transgenic plants had increased transcripts of NCED mRNA, elevated leaf ABA concentrations, increased concentrations of proline, and a significant increase in drought resistance. The transgenic plants also displayed the expected decreases in stomatal conductance, transpiration, and photosynthesis. After 14 days without water, the control plants were dead, but the transgenic plants, though wilted, recovered fully when re-watered. Well-watered transgenic plants grew like non-transformed control plants and there was no effect of the transgene on seed dormancy.

No MeSH data available.


Related in: MedlinePlus