Plants most often found in a garden salad or a breakfast cereal are being used to aid University research on the positive influence of infection of a benign mycorrhizal fungus on different plants.

Using wild carrots, tomatoes, lettuce, and oats, which are representatives of the many different plant families, Roger Koide, assistant professor of biology, is studying the different influences this microscopic fungus has on plants.

Koide, director of the research to study the fungus, said the mycorrhizal fungus infects virtually every plant's roots, usually in a way beneficial to the plant.

In collaboration with Hector Flores, associate professor of plant pathology, Koide has been testing the hypothesis that the fungus may make plants more resistant to herbivores and disease.

"But different plants, even within the same species," Koide said, "often respond differently to the infection. Some plants are benefitted greatly and some are not at all."

Koide has found mycorrhizal fungus promotes the uptake of nutrients from the soil.

"But," says Koide, "it also robs some carbon from the plant."

An essential component to all living organisms on earth, the carbon that is "robbed" from these plants could otherwise be used for the development of the plant's leaves, fruit, roots, and the like, he said.

Koide is studying whether the cost of losing some of the essential carbon due to this fungus is greater or less than the benefit the fungus yields. In most cases, the benefit is greater, he says.

Jim Lewis (graduate-ecology) is working with Koide and has been studying different plants' second generation growth. Plants that were infected with mycorrhizal fungus usually produce seeds that yield faster-growing offspring than plants that were not infected, Lewis said. This is due, in part, to the greater nutrient level intakes of the plants infected with the fungus, he said.

"A plant infected with the fungus appears to be more resistant to diseases than a plant that has not been infected," said Flores.

The fungus seems to induce the plant's roots to produce natural chemicals that repel disease and, when transported to the plant's leaves, may make the plant distasteful to pests and devouring insects, Flores said.

This fungus is marketable, reported Koide, with the greatest market in horticulture and forestry. But at present, the marketability is not terribly high because mass production has not yet been achieved, he added.

"The fungus must be grown on a plant's roots," said Flores, "but we're hoping to learn to grow it alone without the plant." This would allow for the production of large amounts of fungus, said Flores.

Commercial plant producers must sterilize their soil to avoid unwanted bacteria and fungi from contaminating their produces. This sterilization process also kills good fungi and bacteria, said Koide. Therefore, mycorrhizal fungus must be added to supplement the soil, he said.

Koide has recently received a $127,000 grant from the Andrew W. Mellon Foundation under its Conservation and Environment Program to support his work. It is also supported, in part, by a Presidential Young Investigator grant from the National Science Foundation. Most of the money is used to support the graduate students, Koide says.