Genetic Modification

Genetic modification of tobacco began with traditional agricultural breeding and selection practices. The use of modern biotechnology to develop tobacco for commercial purposes, which began in the early 1980s, is only the most recent research and development endeavor. A strain of tobacco that is fundamentally altered at the level of its DNA—its genetic makeup—is said to be "genetically modified," "genetically altered," or, more popularly, "genetically engineered," especially when biotechnology is used. A tobacco strain that is created by the transplantation of a gene from another organism, such as bacteria, is referred to as "transgenic tobacco" and falls under the popular term, "genetically modified organism."

Tobacco is relatively easy to work with for breeding purposes. The plant has a simple flower structure, seeds that are numerous and easily stored, and a ready ability to self-pollinate and cross-pollinate. In addition, it readily incorporates transgenic material to create new reproducible strains of transgenic tobacco. For these reasons, the tobacco plant has been a common organism to use in basic biological research throughout the twentieth century. Moreover, it has been a critical test ground in the general development of transgenic crops. The first transgenic crop, in fact, was a noncommercial variety of tobacco that the biotechnology company Calgene genetically modified to resist the common herbicide glyphosate. The company discovered the resistant bacterial gene in 1983 and first field-tested it in tobacco in 1987. Recent discussions of tobacco genetics highlight the potential of harnessing the plant's biological machinery to organically generate pharmaceutical proteins and industrial enzymes, much the way that bacteria are currently used.

Commercial Efforts

Although productive for research purposes, the commercial importance of tobacco lies in the complex chemical composition of its leaves. Innumerable attempts to improve on tobacco's consumer appeal and profitability for the highly competitive cigarette market have occurred during the last several centuries. Innovations often have come in the form of changes to cultivation methods and manufacturing processes. Genetic modifications of tobacco strains by hybridization (cross-breeding) and selection have been less commercially successful. Attempts to improve on its growth and other characteristics have often been at the expense of taste, aroma, and color qualities of importance in the final cured tobacco leaves. Breeding for disease and pest resistance has historically achieved only limited success as well. One major addition to the family of economically important tobacco varieties was the White Burley variety in 1864; and it is believed to have been the product of a naturally occurring mutation.

Recent advances in biotechnology have offered the promise of a more targeted approach to overcoming longstanding agricultural challenges and fulfilling product development interests, but also have raised public concerns about uncertain ecological and health safety consequences as well as numerous complex regulatory issues for national and international discussion. Europe has been the center of much of the public debate, and the first transgenic organism to be put on the European market, in 1994, was a commercial tobacco that was resistant to the herbicide bromoxynil. A genetically modified tobacco with a viral resistance and a greater yield was reported to have been cultivated on almost one million hectares in China in 1994. Still, commercial development of transgenic tobacco has been smaller compared to other crops because of its lower overall acreage due to lower overall demand for tobacco than for staple agricultural food crops such as corn or wheat.

Controlling of Nicotine Levels

Nicotine content is central to tobacco's identity as a commercial product, and it has been heavily investigated by the tobacco industry. The concentration of nicotine can be highly variable, and it is known to be very susceptible to the agricultural and environmental conditions in which the tobacco is grown. Controlling nicotine levels in tobacco is, thus, a complicated act. Breeding and selection work on high and low nicotine strains dates to the early twentieth century, with two low nicotine strains being isolated in 1907.

In the United States, a strain of tobacco called Y-1, which was genetically modified to be higher in nicotine, became the source of a controversy in 1994 when the Food and Drug Administration publicly revealed Y-1's existence during its attempt to regulate tobacco on the grounds that the tobacco industry manipulated nicotine levels. The FDA found that the Brown & Williamson tobacco company had grown Y-1 in Souza Cruz, Brazil—the export of the seed raising separate legal questions—and used the tobacco, at least temporarily, in several of its brands. Speculation followed on whether the tobacco industry was involved in developing a product to keep smokers addicted. Brown & Williamson maintained that the tobacco was used for blending the product to consumer taste; still, as internal documents reveal, the company was competing with Philip Morris' enormously successful methods for controlling nicotine levels in smoke.

The desire to create a "safe" cigarette has also been a driving force in tobacco genetic research. The Y-1 tobacco had its origin in conventional breeding research conducted during the 1970s by the United States Department of Agriculture in its effort to develop a less hazardous cigarette. The theory was that a cigarette with the same amount of nicotine, but lower in tar, would be desirable but less harmful to the smoker. At various times attention has turned to low nicotine tobacco, and in 2003, the American company Vector Tobacco introduced a reduced nicotine cigarette called Quest. It is produced from tobacco genetically modified to block nicotine synthesis, and the product is being marketed to assist smokers with smoking cessation. Vector is also the manufacturer of the Omni brand, which claims to use a genetically modified tobacco with reduced levels of carcinogens. Other tobacco companies have been involved in biotechnology research to develop less harmful products; however, they have yet to be formally introduced, and none of these products has been scientifically proven to reduce health risks or treat addiction.

See Also Chemistry of Tobacco and Tobacco Smoke; Nicotine.

▌ JOSHUA DUNSBY

BIBLIOGRAPHY

Garner, Wightman W. The Production of Tobacco. Rev. 1st ed. Philadelphia: Blakiston, 1951.

Kessler, David. A Question of Intent: A Great American Battle with a Deadly Industry. New York: Public Affairs, 2001.

Miki, B.L.A, et al. "Transgenic Tobacco: Gene Expression and Applications." In Biotechnology in Agriculture and Forestry, vol. 45. Edited by Y. P. S. Bajaj. New York: Springer, 1999. Pp. 336–354.

United States Department of Agriculture, Agricultural Marketing Service. "Tobacco in the United States. Miscellaneous Publication No. 867." Washington, D.C.: U.S. Government Printing Office, 1979.

biotechnology a scientific process, often genetic in character, to enhance desirable characteristics of plants and animals. Through biotechnology, tobacco has major potential for producing medicines to replace currently expensive drugs for several devastating diseases.

hybridization the practice of cross-breeding different varieties of plants or animals to produce offspring with desired characteristics.

ecology the interrelationships of a natural environment. For example, the ecology of a forest includes animals, plants, water, atmosphere, weather, and land forms.

tar a residue of tobacco smoke, composed of many chemical substances that are collectively known by this term.

synthesis the blending of several elements into a coherent whole.