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Ethanol inducible expression of a mesophilic cellulase avoids adverse effects on plant development.

Klose H, Günl M, Usadel B, Fischer R, Commandeur U - Biotechnol Biofuels (2013)

Bottom Line: However, using an alcohol-inducible expression of the endoglucanase in the plant leaves, we achieved similar enzymatic expression levels with no changes in the crystalline cellulose content.We were able to produce significant amounts of cellulase in the plant leaves without detrimental effects to plant development.These results demonstrate the potential feasibility of an inducible expression system for producing biomass degrading enzymes in plants.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute for Molecular Biotechnology (Biology VII), RWTH Aachen University, Worringerweg 1, Aachen, 52074, Germany. commandeur@molbiotech.rwth-aachen.de.

ABSTRACT

Background: Plant-produced biomass-degrading enzymes are promising tools for the processing of lignocellulose to fermentable sugars. A major limitation of in planta production is that high-level expression of such enzymes could potentially affect the structure and integrity of the plant cell wall and negatively influence plant growth and development.

Results: Here, we evaluate the impact on tobacco plant development of constitutive versus alcohol-inducible expression of the endoglucanase TrCel5A from the mesophilic fungus Trichoderma reesei. Using this system, we are able to demonstrate that constitutive expression of the enzyme, controlled by the doubled Cauliflower Mosaic Virus promoter, leads to lower cellulose content of the plant combined with severe effects on plant growth. However, using an alcohol-inducible expression of the endoglucanase in the plant leaves, we achieved similar enzymatic expression levels with no changes in the crystalline cellulose content.

Conclusion: We were able to produce significant amounts of cellulase in the plant leaves without detrimental effects to plant development. These results demonstrate the potential feasibility of an inducible expression system for producing biomass degrading enzymes in plants.

No MeSH data available.


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Phenotype of transgenic tobacco plants. Strains shown are wild-type N. tabacum SR1 (A). and transgenic tobacco strains with constitutive TrCel5A expression 35::TrCel5A (B). and inducible TrCel5A expression alcR::TrCel5A (C). Plants were grown under photoautotrophic conditions in soil. Images shown are representative of three plants per genetic line.
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Figure 5: Phenotype of transgenic tobacco plants. Strains shown are wild-type N. tabacum SR1 (A). and transgenic tobacco strains with constitutive TrCel5A expression 35::TrCel5A (B). and inducible TrCel5A expression alcR::TrCel5A (C). Plants were grown under photoautotrophic conditions in soil. Images shown are representative of three plants per genetic line.

Mentions: Constitutive TrCel5A expression significantly reduced the growth of tobacco plants and delayed their development compared to wild-type. The mature stems of the transgenic lines were 21–36% shorter than control plants and flowering was delayed (Figure 5). Cross-sections of stems, stained with calcofluor-white, showed no significant difference in cell structure between transgenic T2 lines constitutively expressing TrCel5A and SR1 wild-type plants, although a marginally greater number of small vessels were apparent (Figure 6). In contrast to constitutive expression, inducible TrCel5A expression had no impact on the growth or development of tobacco plants (Figure 5).


Ethanol inducible expression of a mesophilic cellulase avoids adverse effects on plant development.

Klose H, Günl M, Usadel B, Fischer R, Commandeur U - Biotechnol Biofuels (2013)

Phenotype of transgenic tobacco plants. Strains shown are wild-type N. tabacum SR1 (A). and transgenic tobacco strains with constitutive TrCel5A expression 35::TrCel5A (B). and inducible TrCel5A expression alcR::TrCel5A (C). Plants were grown under photoautotrophic conditions in soil. Images shown are representative of three plants per genetic line.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
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getmorefigures.php?uid=PMC3643885&req=5

Figure 5: Phenotype of transgenic tobacco plants. Strains shown are wild-type N. tabacum SR1 (A). and transgenic tobacco strains with constitutive TrCel5A expression 35::TrCel5A (B). and inducible TrCel5A expression alcR::TrCel5A (C). Plants were grown under photoautotrophic conditions in soil. Images shown are representative of three plants per genetic line.
Mentions: Constitutive TrCel5A expression significantly reduced the growth of tobacco plants and delayed their development compared to wild-type. The mature stems of the transgenic lines were 21–36% shorter than control plants and flowering was delayed (Figure 5). Cross-sections of stems, stained with calcofluor-white, showed no significant difference in cell structure between transgenic T2 lines constitutively expressing TrCel5A and SR1 wild-type plants, although a marginally greater number of small vessels were apparent (Figure 6). In contrast to constitutive expression, inducible TrCel5A expression had no impact on the growth or development of tobacco plants (Figure 5).

Bottom Line: However, using an alcohol-inducible expression of the endoglucanase in the plant leaves, we achieved similar enzymatic expression levels with no changes in the crystalline cellulose content.We were able to produce significant amounts of cellulase in the plant leaves without detrimental effects to plant development.These results demonstrate the potential feasibility of an inducible expression system for producing biomass degrading enzymes in plants.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute for Molecular Biotechnology (Biology VII), RWTH Aachen University, Worringerweg 1, Aachen, 52074, Germany. commandeur@molbiotech.rwth-aachen.de.

ABSTRACT

Background: Plant-produced biomass-degrading enzymes are promising tools for the processing of lignocellulose to fermentable sugars. A major limitation of in planta production is that high-level expression of such enzymes could potentially affect the structure and integrity of the plant cell wall and negatively influence plant growth and development.

Results: Here, we evaluate the impact on tobacco plant development of constitutive versus alcohol-inducible expression of the endoglucanase TrCel5A from the mesophilic fungus Trichoderma reesei. Using this system, we are able to demonstrate that constitutive expression of the enzyme, controlled by the doubled Cauliflower Mosaic Virus promoter, leads to lower cellulose content of the plant combined with severe effects on plant growth. However, using an alcohol-inducible expression of the endoglucanase in the plant leaves, we achieved similar enzymatic expression levels with no changes in the crystalline cellulose content.

Conclusion: We were able to produce significant amounts of cellulase in the plant leaves without detrimental effects to plant development. These results demonstrate the potential feasibility of an inducible expression system for producing biomass degrading enzymes in plants.

No MeSH data available.


Related in: MedlinePlus