Aarhus University, Department of Genetics and Biotechnology, Faculty of Agricultural Sciences
The research group Molecular Genetics and Biotechnology works primarily on the nutritional quality and derived environmental effects of barley, wheat and ryegrass for animal feed.
For barley and wheat the focus is on improving the bioavailability of phosphate and to improve the amino acid composition and protein concentration of the grain. With respect to phosphate we primarily work on improving the phytase potential of the grain by heterologous expression of microbial phytases that are stored in the grain. For monogastric animals this strategy is as efficient for degrading phytate in cereal based feed as the exogenous application of phytase. Recently we have also cloned the entire portfolio of endogenous phytase genes from barley, wheat and rye and are currently studying their temporal and spatial localization in the grain. The objective is to achieve a phytase potential in the grain that can obviate the use of rock phosphate supplementation to animal feed.
With respect to amino acid composition we have been successful in achieving a marked improvement in the amino acid profile of the barley grain by increasing the amounts of essential amino acids and reducing the amounts of proline and glutamine. The latter two amino acids cannot be fully utilized in cereal based feed but are degraded and the nitrogen excreted, thereby having a significant effect on the environment. The changes were achieved by altering the relative proportions of storage proteins in the grain by antisense suppression of the storage protein fraction with the poorest amino acid profile. Currently, we are screening a large collection of high protein barley lines to look for useful variation in protein quality and quantity and undertakes studies to assess the regulation of storage protein synthesis.
Additional projects in barley and wheat comprise studies on improving nitrogen and mineral mobilisation from the vegetative parts of the plant to the grain during senescence as well as transgenic strategies for increasing the iron and zinc content of the grain.
In ryegrass the focus is on reducing the lignin content. Here, the approach is entirely genetic involving mapping of relevant genes as well as studying particular candidate genes.
Our core technologies comprise state-of-the-art molecular biology, biochemistry, molecular genetics (mapping populations, BAC libraries), transcriptome analysis using commercial DNA microarrays and in-house fabricated, smaller focused microarrays, transformation and laser capture microdissection for studying gene expression profiles at the cellular level. In transformation we work on the implementation of improved technologies, including the cisgenesis concept where only the plants own genes are used.
Scientist involved in COST Action Feed for health: Preben Bach Holm