Monheim, Germany
February 24, 2011
In the future, the earth will have to feed an ever growing number of people. Worldwide harvest yields are however unable to keep pace with the planets growing population, and the consequences of climate change are increasingly threatening cereals, fruit and vegetables. The situation is further exacerbated by the increasing scarcity of resources. Biotechnology in combination with state-of-the-art breeding methods could contribute to a solution: These approaches enable a specific selection and cross-breeding of plant traits, creating more robust and higher-yielding varieties.
Scientists at Bayer CropScience are combining conventional plant breeding with modern biotechnology: Dr. Jan van den Berg (left) and Paul Degreef check a new variety of tomato in the green house, where the plants are trained up white strings.
Agriculture is facing enormous challenges caused by the growing world population. According to UN estimates, it is expected to exceed the 7 billion mark already this year. In 2050 the population of the earth will be more than nine billion people – all of whom will need enough to eat. In addition, the climate change threatens to worsen the situation even further. For example, the World Bank estimates that five to ten million hectares of land are lost each year due to soil degradation. The entire area of land used for agriculture in Germany amounts to about 17 million hectares.
To safeguard our food supply in the future and overcome these global challenges, farmers around the world need new approaches. The agricultural research scientists at Bayer CropScience are therefore committed to plant biotechnology. Molecular biologists are now making a crucial contribution to the work of plant breeders with new methods. In the coming years, they plan to further accelerate plant breeding and develop fruit, cereal and vegetable varieties with new properties. “Biotechnology allows us to look deep inside the plant – through leaves, stems and roots into the genetic material in the cell nucleus,” explains Dr. Johan Botterman, Head of Product Research for BioScience at Bayer CropScience in Ghent, Belgium. The requirements on the plants of the future will be enormous and next to impossible to achieve with conventional breeding based solely on selection and cross-breeding. After all, it takes many years to develop a new variety of tomato or rice. The plants have to prosper and form fruit before their crossbred progeny is available for the next cycle of selecting and crossing. In addition, the breeders have to analyze thousands of offspring and test them to see whether the desired traits have been passed on.
Cucumber art in the laboratory: Biotechnology experts and plant breeders at Bayer CropScience sprout vegetable seeds in a Petri dish filled with a growing medium
From breeder to plant designer
Biotechnology methods considerably accelerate plant breeding and complement the plant breeders’ many years of experience. A process that takes about ten years with conventional breeding, for example, can now be completed in roughly half the time. To develop new varieties, the biotechnology experts at Bayer CropScience in Ghent collaborate closely with their colleagues from Nunhems, the vegetable seed specialists at Bayer CropScience, in interdisciplinary teams: They enhance the taste, shelf life and processing properties of fruit and vegetables or make crops such as rice and oilseed rape more tolerant to stress factors such as drought, pests and diseases.
Search for the genetic fingerprint
One instrument in the plant experts’ repertoire is the molecular analysis. BioScience researchers examining genetic material in the laboratory can precisely determine how the individual seedlings of a new breed differ. “Thanks to advances in molecular biology, it is now possible to describe plant properties in terms of their genes. The more we find out about plants by means of biotechnology, the better we can recognize the mechanisms and genetic networks behind specific characteristics,” explains Botterman. Properties such as enhanced photosynthesis performance or nutrient uptake are generally based on the complex interplay of several genes. Once this kind of network has been identified, it can also be diagnosed in other plants, providing valuable information for breeding. “Molecular marker analysis also allows us to identify a number of genes and thus a number of traits in one plant at the same time,” says Benjamin Laga, one of the group leaders of the Genetics team at Bayer CropScience in Ghent. This gives the plant scientists a genetic fingerprint that characterizes the individual traits of a plant, just like a barcode identifies a product.
One advantage of marker analysis is that it works even with young seedlings. For example, to identify whether the fibers of a cotton plant will be particularly long, strong and fine, it is sufficient to take a piece of the stalk or a leaf into the laboratory. “This kind of targeted selection saves enormous amounts of development time, and space in the greenhouse and the trial fields – and therefore also money,” says Dr. Jan van den Berg, Global Head of Molecular Breeding at Nunhems, referring to an economic aspect of molecular biology in plant breeding. Molecular markers make possible an enormous range of new varieties: for example, Nunhems has developed more than half of its 2,500 varieties of vegetable seeds within the past six years. “There is a rising demand for higher yields but also for quality traits such as new tastes or more aroma,” says Paul Degreef, Global Head of Breeding at Nunhems.
Targeted evolution in genetic material
The biotechnology experts have to precisely understand the genetic material if they want to search for specific genes. The genetic codes of many crop plants are already known. For example, the oilseed rape genome was deciphered by a team headed by Dr. Bart Lambert, Oilseeds Product Research Manager at Bayer CropScience, together with several partners. Working from 30,000 plant genes, the Bayer scientists are now developing enhanced oilseed rape varieties using another biotechnology method known as reverse genetics.
The method is called reverse genetics because, unlike before, the scientists do not use the external appearance of a plant to draw conclusions about the responsible genes. Instead, they specifically modify a gene or genetic network to give the plant a new trait. They do this by treating the seed with a substance that triggers mutations, distributed randomly throughout the entire plant genome. “Changes like these happen in nature, too. But we accelerate this evolutionary process in a particular direction,” explains Lambert. From thousands of randomly mutated seed samples, the scientists select the ones that carry a promising mutation in their genetic material. To do this, the BioScience researchers have created a very fast and accurate tracing method which multiplies and sequences the genetic modules in a precisely defined gene segment.
Shatterproof oilseed rape pods
Bayer CropScience wants to use reverse genetics to solve a problem that affects many farmers who grow oilseed rape: the seeds often fall from the ripe pods onto the ground before they can be harvested, making them useless for further processing. The BioScience researchers are therefore developing plants with pods that are more resistant to shattering. They have identified a specific gene in the genome that is involved in the development of a tissue in the pod that holds the “packaging” of the seeds together. When the crop ripens, this tissue breaks down. But under unfavorable conditions, this happens too early and the seeds fall out of the pods prematurely. The plant scientists have changed the genetic activity and thus developed oilseed rape plants with shatterproof pods.
Four genes in the genetic material of oilseed rape are responsible for opening the pods. Scientists use a substance to stimulate random mutations (mutagenesis) and breed seedlings. They cross only plants in which one of the relevant genes is inactive. In this way, they develop oilseed rape plants with pods that do not open until they are harvested. Using reverse genetics, breeders can accelerate natural evolution. (Click on graphic to enlarge)
Genetic research has revolutionized modern plant breeding. Molecular markers and advances in genome deciphering assist in breeding plants with enhanced traits markedly faster. The use of biotechnology to develop varieties that are more tolerant to diseases, pests and climate-related stress also has a huge impact on the development of sustainable agriculture. The demand for raw materials and energy can be considerably reduced, as less fertilizer and fewer pesticides have to be applied to the fields with machinery or the plants themselves require less water.
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