Arabidopsis Genome Initiative
Arabidopsis thaliana is a weed in the mustard family whose rapid growth cycle and small size make it an ideal experimental model for plant biology research. More than 2,500 laboratories and 8,000 scientists worldwide are using a new generation of tools to probe this plant's genome, revealing processes common to all plants.
The process. The Arabidopsis Genome Initiative (AGI) began in 1996, unifying the efforts of international teams who had been decoding this important genome sequence since the early 1990s. Representatives from each of the major Arabidopsis sequencing centers met in August 1996 at the National Science Foundation (NSF) in Arlington, VA to agree on a collaborative approach. In the U.S., an interagency program began in 1996 with funds from NSF, the U.S. Department of Energy and the U.S. Department of Agriculture. The European Union, the Government of France, and the Chiba Prefectural Government in Japan similarly support AGI research.
The future. Even as the genome sequence neared completion, NSF began the next phase of Arabidopsis thaliana genome research. NSF's new 2010 Project seeks to determine the functions of 25,000 Arabidopsis genes over the next decade.
The tools and applications. Arabidopsis researchers use and have developed a variety of tools, including:
All of these tools let scientists systematically dissect the Arabidopsis genome, leading to the completion of its sequence, the identification of many individual genes' functions and a better understanding of plant behavior in general. Studies of Arabidopsis have improved our understanding of disease resistance, root development and other important plant processes. Because the pace of this research is extremely rapid, the following highlights are by no means comprehensive.
Improving Disease Resistance. Certain varieties of crops are more resistant than others to particular viral, bacterial, or fungal pathogens. Achieving disease resistance is a major goal of most plant-breeding programs, but such hybrids are timeconsuming to produce when compared with genetic modification. The molecular cloning of an Arabidopsis disease-resistance gene called RPS2 has significantly added to our understanding of how this gene and similar ones work in economically important plants.
Understanding Photosensitivity. By analyzing Arabidopsis, scientists have shown that plants respond to light by integrating various input signals through a complex genetic network. Cloned genes revealed the previously undetected chemical nature of a blue-light receptor in Arabidopsis, suggesting the existence of such a mechanism to trigger physiological responses in higher plants. This could lead to plants that are able to grow with less light.
Creating Healthier Edible Oils. Genes that guide the synthesis of oils in Arabidopsis are closely related to such genes in commercial crops. This relationship is being exploited to produce plants with healthier edible oils. About one-third of the calories in our diets comes from soybean or other vegetable oils. Most vegetable oils are not suitable for food, however, because they are highly polyunsaturated. Fatty-acid genes from Arabidopsis have counterparts in soybean, canola, and several other oil crops.
Manufacturing Biodegradable Plastics. The Arabidopsis genome sequence may lead to new biodegradable plastics. Scientists have introduced genes from the bacterium Alcaligenes eutrophus into Arabidopsis, causing a biodegradable plastic (polyhydroxybutyrate or PHB) to accumulate. With up to 20-percent of the modified plant's dry weight made up of PHB, several companies have begun programs to develop such plastic-producing crops.
Making Vegetables and Fruits Cheaper and Hardier. The gas ethylene affects plant growth and development. The agriculture industry uses it to control the ripening of fruits and vegetables and the aging of flowers. By preventing plants from producing or responding to ethylene, scientists could develop crops that ripen faster or slower, as desired. An Arabidopsis gene mediates the biological effects of ethylene, and researchers have isolated a mutant form that could make plants completely resistant to the gas. This could significantly slow down the rates at which fruits ripen and flowers wilt, keeping them fresh longer.
Improving Erosion Resistance. The root system of Arabidopsis is a model for studying how these plant organs form. Scientists have found a variety of Arabidopsis genetic mutations that affect root development and determine whether plants are resistant to soil erosion.
Understanding How Plants Flower. Floral growth begins with development of formative plant tissue called the meristem, which may branch to form several floral meristems, each with a separate flower. Arabidopsis research has shown that interaction between meristem genes dictates the growth of floral organs such as petals, sepals and stamens.
See also: List of Arabidopsis links.
For a streaming video about the Arabidopsis genome sequence, see: http://www.nsf.gov/od/lpa/news/press/00/pr0094.htm
The National Science Foundation (NSF) is an independent federal agency that supports fundamental research and education across all fields of science and engineering. In fiscal year (FY) 2016, its budget is $7.5 billion. NSF funds reach all 50 states through grants to nearly 2,000 colleges, universities and other institutions. Each year, NSF receives more than 48,000 competitive proposals for funding and makes about 12,000 new funding awards. NSF also awards about $626 million in professional and service contracts yearly.
Useful NSF Web Sites: