Improved Productivity and Resource-use Efficiency in Crop Plants (Biomass)

Abstract

Optimizing crop yields is one of the major current challenges facing agricultural research. One way to boost productivity is to enhance photosynthetic efficiency, because photosynthetic carbon assimilation is a bottleneck that restricts plant growth.

We have developed a novel approach to enhance resource-use efficiency, promote growth and increase yields in tobacco and potato by introducing a glycolate dehydrogenase multi-subunit fusion protein.

© Fraunhofer IME | Gerta Nölke

Improved biomass in DEFp transgenic tobacco plants. DEFp producing line (right) and control plant (left)

DEFp expression in the plastids of potatoes leads to a significantly higher tuber yield (right) compared to the control (left)

Approach

Glycolate dehydrogenase (GlcDH), the first enzyme in the bacterial glycolate catabolic pathway, is a multiprotein complex comprising three subunits (D, E and F). GlcDH activity is affected by the unbalanced expression of these subunits. To avoid the need for multigene transformation and to ensure balanced expression of the three subunits, we designed a recombinant glycolate dehydrogenase polyprotein (DEFp). The engineered polyprotein retained the functionality of the native GlcDH complex when expressed in the bacterium Escherichia coli.

The DEFp construct was introduced into tobacco and potato chloroplasts.

  • Recombinant DEFp was active in planta, improving the uptake of carbon dioxide and reducing photorespiration.
  • Transgenic tobacco plants produced more biomass, especially under limited nitrogen availability (Figure 1).
  • Transgenic potato produced higher carbohydrate levels in leaves, increasing the tuber yield by 2.3-fold (Figure 2).

 

Conclusion

The expression of recombinant DEFp in tobacco and potato plastids has a significant impact on carbon metabolism, improving biomass accumulation and nutrient-use efficiency under nitrogen starvation conditions.

This novel approach has the potential to increase the biomass and yield of diverse crops.

 

Project Duration

2007-2010

The project was supported by BMBF-GABI Improve FKZ 0315038C

Project Partners

Bayer Crop Science
Forschungszentrum Jülich
Leibniz-University Hannover

Publications

Nölke, G., Houdelet, M., Kreuzaler, F., Peterhänsel, C., Schillberg, S., 2014. The expression of a recombinant glycolate dehydrogenase polyprotein in potato (Solanum tuberosum) plastids strongly enhances photosynthesis and tuber yield. Plant Biotechnol J 12, 734–742. https://doi.org/10.1111/pbi.12178