A Rose Is a Rose Is a Mustard Weed
There are approximately 250,000 different species of flowering plants, all believed to derive from a common ancestor. While plants have adapted to a multitude of terrains, climate conditions, and selected breeding efforts over the millennia, the process of evolution ensures that they remain related in fundamental ways. At the molecular level, for example, what causes a rose bush to flower is not terribly different from what occurs in a radish plant. Other characterists also appear to be similar across species, such as the fruit ripening process and the internal clock that tells plants when to open their pores in anticipation of daylight. In fact, the physiology and biochemistry of plants display such uniformity across species that one can say, without too much exaggeration: When you've seen one flowering plant (at the molecular level), you've seen them all.
This essential truth has altered the course of study in plant biology, a field once dominated by research into individual crops, such as corn or wheat. Today, plant biology has its own model organism, the flowering mustard plant Arabidopsis thaliana; consequently, research in the field now resembles other types of broad basic research, such as that done on bacteria or animals.
Considered a weed because it is uncultivated and grows in profusion, Arabidopsis nonetheless engages the attention of a global research community. The researchers, and agencies such as NSF that support them, expect that by analyzing the structure and functions of Arabidopsis, they are laying the groundword for analyzing most other plant species.
The project has greatly accelerated the practical application of basic discoveries in agriculture and forestry. Genetically engineered species are beginning to appear, and many believe they signal the beginning of a revolution in plant breeding.
In one such area of discovery, scientists have identified genes involved with the regulation and structural forms of flowers. Knowledge of these genes has made possible the genetic engineering of plants other than Arabidopsis. For example, aspens normally flower only after they have attained a height of 30 feet, which can take up to twenty years. A genetically transformed aspen, however, flowered in only six months, when it was just 2 inches tall. Commercial tree growers have always wanted to control the timing of floral and fruit production, as well as the closely related reproductive cycle. The technology is also being tested in fruit and timber trees.
In another research initiative, health concerns over saturated fat and hydrogenated vegetable oils are motivating a search for edible oils that pose no threat to human health. The pathways by which plants produce edible unsaturated oils have been elucidated and the responsible desaturase genes cloned from Arabidopsis. The Arabidopsis genes were used to identify the corresponding genes in soybeans and other crop plants, whose oils account for approximately one-third of the calories in the American diet. At present, most plant oils are chemically hydrogenated to keep them from turning rancid. The availability of the desaturase genes raises the possibility that nutritionally desirable edible oils can be produced from plants without the need for chemical modification. Agrichemical producers have begun field trials with modified soybeans and other plant species.