RESEARCHERS at the Danforth Center are also studying how plant roots supply important nutrients and respond to stress. Geneticist Daniel P. Schachtman's lab is examining how plant roots take up minerals from the soil and is determining how plants adapt these mechanisms to problem soils.
In many areas of the world, salty irrigation water and salt-damaged soils severely limit crop production. Plants growing in saline soils take up excess sodium and potassium, which stunts their growth. Reducing uptake of sodium allows some plants to grow faster and produce more. Since plants are likely to rely on potassium transport proteins for sodium uptake, Schachtman's lab is working to delineate function and ionic selectivity for the potassium uptake protein class of potassium transporters in Arabidopsis.
Members of his lab have also been searching for plant proteins that take up zinc from the soil by using yeast cells deficient in zinc uptake and for plant genes that restore the yeast cells' ability to take up zinc. They have found two such putative zinc transporters in rice using this method. In addition, Schachtman's lab is looking for changes in zinc uptake and seed zinc content in transgenic barley overexpressing an Arabidopsis zinc transporter. By some estimates, nearly half of the world's people fail to obtain adequate amounts of zinc from their diet. This work may lead to modification of plant food staples so that they are better at taking up zinc from soils and to increased zinc bioavailability in foods.
|Jaworski (left), Schachtman, and Smith
MIKE BIZELLI/DANFORTH CENTER PHOTOS
Biochemist Thomas J. Smith uses the tools of X-ray crystallography to understand how pathogens infect and harm plants--and in doing so, he hopes to provide new ways of controlling such pathogens. His lab is studying a rare example of symbiosis between a virus and its fungal host. The UMV4 virus permanently resides inside its host of choice--Ustilago maydis, or corn smut--and relies on the fungus for its replication and survival. In return, the virus produces a 105-amino acid toxin called KP4 that kills competing strains of fungus. Structural studies and biochemical assays show that the toxin kills by blocking calcium channels in foreign fungi. The group hopes to use the information to make plants resistant to other fungi, Smith says. "We hope these studies will reveal the Achilles heel of these fungi."
Unusual seed oils that might have useful industrial applications are the focus of the laboratory of biochemist Jan G. Jaworski. He hopes to use information gleaned from the study of seed oil metabolism to modulate their composition.
His lab is investigating structure-function relationships in 3-ketoacyl synthases, a class of plant enzymes that participate in fatty acid and oil biosynthesis and elongation. The researchers have cloned, purified, and characterized 3-ketoacyl-ACP synthase III from spinach, a soluble protein that catalyzes the first condensation reaction. In addition, they are working to characterize a membrane-bound condensation enzyme from Arabidopsis, the 3-ketoacyl-CoA synthase FAE1 KCS.
In a separate project, funded by Dow, Jaworski is using such metabolic information to guide insertion of genes from exotic plants into Arabidopsis that enable production of seed oils of unique and industrially interesting compositions. "Such plants could represent a renewable, domestic source of chemical feedstocks and polymer precursors," Jaworski says. Plants could also provide novel chemical feedstocks not available from petroleum-based sources, he adds.
The Danforth Center is also home to the International Laboratory for Tropical Agricultural Biotechnology. Since its founding in 1991 by Beachy and Director Claude M. Fauquet, ILTAB has sought to improve tropical crops, to develop the research capacity of developing countries by training scientists and transferring technology, and to coordinate global biotechnology research on tropical crops.
ILTAB's current focus is the tuber cassava, also known as manioc, a dietary staple worldwide but most important to African farmers, who produce 90 million metric tons of cassava annually. In Africa alone, an estimated 3550 million metric tons of cassava--representing 4055% of annual crop production--are lost per year to viral diseases, Fauquet tells C&EN. In the absence of a winter season, these viruses flourish year-round. Cassava is propagated from cuttings taken from older plants, allowing viruses to spread rapidly. These unique conditions lessen the effects of conventional means of control, Fauquet says.
Although cassava represents food security for many people, it has limited nutritional benefit. It provides negligible amounts of protein, a scarce commodity in many regions of Africa. And because cassava flour has a different biochemical composition and lacks the proteins required for bread production, Africa must import tons of wheat flour each year to meet its bread needs.
Fauquet and ILTAB are working to create transgenic cassava varieties that are resistant to viral disease, have improved starch content, and contain more protein. To do so, the Danforth Center negotiated royalty-free rights to the enabling genetic engineering technologies from Monsanto. The agricultural biotechnology firm granted the rights with no strings attached, Fauquet notes.
"I don't know of any other research center that I have ever visited that has a greater potential contribution to the well-being of the world."
BIOTECH FIRMS like Monsanto have little commercial interest in developing world crops like cassava, so they lose nothing by this kind of generosity, Beachy notes. But many Danforth Center researchers are working to create technology of interest to farmers in both developing and developed countries. It's crucial that the center share the benefits of technology developed there with scientists and farmers in both rich and poor nations, Beachy adds.
So Beachy has instituted an intellectual property policy that takes inspiration from its underlying focus on creating technologies and tools to benefit the developing world. The Danforth Center's Office of Technology Management is charged with making sure that future licensing arrangements for technology developed at the center are crafted in an equitable way.
The Danforth Center works with a range of different companies, Schubert points out. But the center retains the rights to any technology developed to address needs in developing countries. A number of universities and research institutions are warming up to the idea of retaining intellectual property rights for humanitarian uses, notes Gary H. Toenniessen, director of food security at the Rockefeller Foundation. The Danforth Center is leading the charge.
Arizona State's Arntzen agrees. "Roger [Beachy] is pioneering innovative intellectual property management geared to helping both the developed and the developing worlds benefit from agricultural research," he says. "He is creating a good model for how it can and should be done."
Beachy sees the Danforth Center as a model for more than just intellectual property management. He hopes the center will assume a place at the forefront of plant science research, a field that he and founders of the Danforth Center--as well as many other plant scientists--think is just as vital to the future of the world as medical research.
|OUTREACH Training scientists from the developing world like India's Vanitharani Ramachandran (right) is an important mission of the Danforth Center, ILTAB Director Fauquet says.
MIKE BIZELLI/DANFORTH CENTER PHOTO
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