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April 30, 2002

Plant scientist receives Purdue agricultural research award

WEST LAFAYETTE, Ind. – Most agricultural scientists either focus on problems in industrialized nations, such as the United States, or on problems in developing nations.

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But problems surrounding the plant nutrient phosphorus occur in both industrialized and developing nations – albeit for different reasons – and that's why the research of Purdue University's Kashchandra G. Raghothama, professor of horticulture, is so significant.

Raghothama's laboratory was the first to isolate and characterize the genes responsible for phosphorus uptake. As a result of his research on this basic plant nutrient, Raghothama has received the 2002 Agricultural Research Award from the Purdue School of Agriculture.

The award was presented Monday (4/29) on the Purdue campus.

William R. Woodson, associate dean of the School of Agriculture and director of the Office of Agricultural Research Programs, says Raghothama's insights into the genetic basis of phosphorus use in plants has been a major contribution to agriculture, both in Indiana and internationally.

"This work has led to a number of strategies to improve phosphorus efficiency in crop plants, and researchers around the world are making use of his discoveries," Woodson says. "Dr. Raghothama's research is of tremendous importance to crop productivity around the globe."

Phosphorus is one of three major nutrients needed by plants. But unlike nitrogen and potassium, phosphorus is not readily available to plants, so it must be applied in fertilizer.

In the United States and in Europe, where animal production is a significant part of agriculture, there is an excess of phosphorus in the soil, arriving in the form of manure spread on fields as fertilizer. If the phosphorus levels in the soil become too high, the phosphorus can run off into streams and lakes. Because phosphorus is a basic plant nutrient, this runoff can lead to an overgrowth of algae and aquatic weeds which can choke out the fish living in the water.

In the tropics, particles in the highly acidic soils bind phosphorus so well that little of it is available to crops. Also, poor farmers in those developing nations often can't afford to buy fertilizer. The result is crops that are starved for the nutrient, greatly reducing yield. The problem is especially acute in South America, Africa and Asia.

"It's unfortunate that in the areas of the world where we have an enormous population and a big demand for food that the soils in these areas are most affected by phosphorus deficiency," Raghothama says.

After millions of years of evolution, plants have developed many methods of extracting the tightly bound phosphorus from the soil. When plants sense that there isn't enough phosphorus available for growth, they respond in various ways. Some plants grow more roots or more root hairs; other plants excrete chemicals from their roots that dissolve the bonds between the phosphorus and the soil, making more of the nutrient available. Still other plants are more efficient in how they use phosphorus within their cells.

"So there is a constant struggle for acquiring phosphorus in plants," Raghothama says. "This has allowed plants to develop many wonderful mechanisms in both their roots and the above ground parts to survive under phosphorus starvation."

Raghothama continues to investigate the genetic responses to phosphorus deficiency. He is now focusing on what he calls the "switches and buttons" that determine how a plant responds to phosphorus starvation.

"Once we get a handle on what makes the plants respond, the genetic switches that are there, we will be able to manipulate these in a logical way to develop plants that are much more efficient in how they use the nutrient," he says.

This would be a boon to farmers in developing nations, but it also would aid farmers in the United States.

"If our Midwestern crops could better utilize phosphorus, we could reduce the amount of it we apply to the soil, and therefore reduce the possibility of environmental contamination," he says.

The annual Purdue Agricultural Research Award recognizes a scientist with less than 15 years experience beyond their doctorate who has demonstrated a high level of excellence in research and made significant contributions to agriculture, natural resources and the quality of life for Indiana citizens.

The recipient is selected by a committee of peers and receives a $1,000 honorarium, which is funded by earnings from the Charles Guthrie Patterson Memorial Endowment and the Matthew Morgan Hamilton Fund. The recipient also receives $5,000 in funding to support his or her research.

Woodson says that in addition to being a top researcher, Raghothama also is an excellent teacher. "He has a talent for explaining this subject to his students," Woodson says.

Raghothama came to Purdue in 1988 after receiving his doctorate from Washington State University. He is a native of Bangalore, India.

Raghothama's research has been supported by the U.S. Department of Agriculture, the United States-Israel Binational Agricultural Research and Development Fund and the prestigious McKnight Foundation.

Writer: Steve Tally, (765) 494-9809;

Sources: K.G. Raghothama, (765) 494-1342;

William R. Woodson, (765) 494-8360:

Ag Communications: (765) 494-2722; Beth Forbes,;

Hydroponically grown corn and tomato plants (among others) allow Kaschandra G. Raghothama to monitor plant utilization of phosphorus. For his research, Raghothama has earned the 2002 Agricultural Research Award from the Purdue School of Agriculture. (Agricultural Communications Photo by Tom Campbell)

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