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A green view - plant genome research

Research into the plant genome reveals many fundamental mechanisms, some of which are also found in animals and human beings. Research increases the possibility of application, in particular for the improvement of food, animal feed and energy plants. However, there is more to it than just transgenic plants.

Plant breeders have been exploiting the genetic potential of plants for many thousands of years. Advantageous spontaneous mutations that benefit human beings have always been the ones that are selected and the genetic material of different species has been recombined by crossbreeding. These processes have been very successful despite the lack of knowledge about molecular relationships, which has meant that the development of such processes has been very slow. It can be seen how, over many thousands of years, an inconspicuous brome in Central America developed into modern maize and became one of the most important food and feed stuffs of the modern world.

Gregor Mendel, the father of genetics © wikipedia.de

In modern times, society's demand for the rapid development of high-yield and extremely resistant plant varieties has increased, as has the thirst for knowledge about the mysterious processes that lead to changes and variants in plants. Systematic research into the inheritance of certain properties started with Gregor Mendel, an Austrian monk and biologist. In the middle of the 19th century, Mendel cultivated and tested around 28,000 garden pea plants from which he deduced the laws of inheritance. Mendel's rules - also known as the Mendelian Laws of Heredity - are still the basis of modern genetics although many important exceptions to them have been discovered: for example, transposons (jumping genes) and the translocation of individual genes. These two phenomena do not fit into the laws of Mendelian inheritance, which does not diminish their fundamental importance in any way. 

Molecular biology creates breakthroughs

Modern molecular genetics has led to groundbreaking insights into the plant genome, which has advanced genome research in general and the further development of agricultural plants in particular. The one-year thale cress (Arabidopsis thaliana) was the first higher plant whose entire genome was sequenced (2000, published in Nature). The Arabidopsis genome has about 25,500 genes. In 2002, the genome of the two rice varieties Oryza sativa ssp. indica and Oryza sativa ssp. japonica (published in Science) was sequenced.

Arabidopsis thaliana flower seen with a scanning electron microscope. © Jürgen Berger / Max Planck Institute for Developmental Biology

Arabidopsis can be easily cultivated, it grows quickly and it can be easily handled for molecular genetic examinations, three properties that have made this particular plant the most popular laboratory plant in the world. Many discoveries that were initially made in Arabidopsis are of a fundamental nature and are not only valid for plants, but also for animals. One such example is the genetic regulation mechanisms that are mediated by RNA.

Major impulses for the application of plant genome research come from basic research. Functional genome research, i.e. the investigation of the biological function of plant genes, is one major focus. In 2000, the BMBF, in cooperation with more than 25 companies, started the GABI research programme with the objective of making agricultural crops "fit for the future". GABI focuses on both basic and applied research with each type of research having five priorities to which individual projects are then attached.

Research programme GABI – the plant genome as challenge

The plant genome research initiative GABI is jointly run and financed by the German Ministry of Education and Research (BMBF) and partners from industry. The objective of GABI is to strengthen the scientific basis of plant genome research in Germany, establish a close and permanent network between academic and industrial research and enable the rapid transfer of research results into practice by using an efficient knowledge and technology transfer system that enables the enhanced development of products with a high value creation potential in the fields of agriculture, forestry, horticulture and the cultivation of ornamental plants, nutrition, health, pharmaceutics, chemistry and environment.

Major goals are the development of high-yield plant varieties, disease resistance, improvement in taste and better storage. Special focus is also put on genome research and the further development of plants that produce medically relevant products or substances that are important for human nutrition (vitamins, specific fatty acids or carbohydrates). The goal is therefore not only to increase plant yield in terms of quantity, but also to increase the quantity of useful substances per plant.

In general, each individual GABI project involves scientists working in cooperation with breeders and experts from the industry. The research is based on a huge quantity of genomic and phenotypic data that can only be administered and used effectively with professional data management tools. The biometric and bioinformatics tools are being developed in a project coordinated by the University of Hohenheim. The article "Leaving nothing to chance - researchers to develop methods for knowledge-based plant breeding" features the approaches used by the Hohenheim scientists.

In addition to plants used for the production of food, energy plants have been becoming more and more important for researchers and producers. Rapeseed is used to produce plant oil fuel and biodiesel, maize and other crops and potatoes are used to produce bioethanol. Commercial genome research is also used for the production of ornamental plants. The Stuttgart-based company Ornamental Bioscience GmbH is working on the development of ornamental plants such as poinsettia, impatiens and geraniums in order to produce new attractive varieties. Ornamental Bioscience also focuses on plant resistance and is investigating plants that are more resistant to pathogens, drought and cold, using classical breeding methods (as laid out by Mendel) as well as genetic engineering methods.

Genome research enhances modern breeding

The use of genetic engineering methods does not always automatically lead to the production of transgenic plants. Molecular markers and genome sequencing are for example used to improve the breeding of plants. The use of such methods enables scientists to introduce resistance genes of related species into high-performance plant varieties.

The phenomenon of heterosis is an alternative to genetic engineering. Heterosis refers to the possibility of obtaining a genetically superior individual (hybrid) by combining its parents’ virtues. Hybrids resulting from the crossing of two degenerated inbred lines can lead to yields that are up to 70 per cent higher. The phenomenon of heterosis is now being investigated using molecular biology methods with the aim of using plant heterosis optimally for plant breeding purposes. The current state of research into hybrid breeding was recently discussed at the heterosis conference (Renaissance of Hybrid Breeding) held at the beginning of September 2009 at the University of Hohenheim.

Website address: https://www.biooekonomie-bw.de/en/articles/dossiers/a-green-view-plant-genome-research