By Flora Mauch, Checkbiotech

Researchers from Michigan State University have identified two cooperating genes whose products mediate leaf growth.

Temperatures drop, the last leaves fall off the trees, and soon snow will cover the country I live in, Switzerland. Winter is approaching, and people already enjoy the special mood before the holiday season. But what would winter be like without being without the prospects of spring that will follow?

When the lifelessness of winter is followed with a burst of growth, we often are left to wonder how nature orchestrates this change. Researchers who looked into the question of how leaf growth is regulated and what genetic and biochemical factors determine leaf growth, are Drs. Jeong Hoe Kim and Hans Kende from the DOE Plant Research Laboratory at Michigan State University.

In previous studies, Dr. Kende’s group identified the role of the Arabidopsis thaliana growth-regulating factor (AtGRF) gene family, whose members encode factors that play a regulatory role in the growth and development of leaves. These factors are proteins that bind to DNA and function to initiate, enhance, or inhibit gene expression. In their latest studies, Drs. Kim and Kende discovered a family of three genes called GFR-interacting factors (GIFs) as well as their role in leaf growth. As the name implies, GIF cooperates with GRF in influencing gene expression, thereby affecting the growth and shape of leaves. Such a protein is called a coactivator in the world of molecular genetics.

To prove their findings, Dr. Kende and his laboratory showed that transgenic Arabidopsis plants expressing high levels of GIF resulted in a similar phenotype as transgenic Arabidopsis plants expressing high levels of GFR. Either transgenic plants produced larger leaves when compared to control plants.

In the course of their experiments, Drs. Kim and Kende also noticed that the GIF transgenic plants were sterile. With the inability to pass on the added genes, transgenic plants expressing higher levels of GIF would not be able to pollinate neighboring crops. This would be beneficial to growers who are concerned about genetically modified plants crossing with other plants.

Another fact supporting the notion that GIF acts as a coactivator is its sequence similarity to human SYT, which is a well-known coactivator.

Now that more is known about the development of plant leaves, the question arises of how this knowledge could be used in agriculture. One example can be found in medicinal plants. Often medicinal chemicals are found in the leaves of plants. In such cases, a genetically engineered plant producing higher levels of GIF, would have larger leaves, thereby increasing the amount of medicinal compounds that growers could harvest. The increased yields could reduce costs to the grower as well to the consumer in form of more affordable medicinal drugs.

Dr Kende’s work is a considerable step in plant biology and should lay the foundation for promising agricultural improvements in the future.

Flora Mauch is a Science Writer for Checkbiotech in Basel, Switzerland and is currently studying Biology.