The Role of P-Proteins in Plant Insect Interaction

Washington State University, Pullman WA

Investigators

Abstract

Sugars synthesized by photosynthesis have to be distributed over the entire plant body. They are crucial for all cells, since they represent the primary energy source for plant life. The system responsible for distribution within plants is the phloem which consists of tube like cells that form a microfluidic network within the plant body. Due to its high content of sugar, the phloem is a primary target for pests like aphids and mealybugs. Currently, infestation of crop plants by such pests causes substantial economic damage and the dependence on pesticides. An increasing number of consumers, however, are concerned about the occurrence of pesticides in food. Numerous studies have demonstrated that pesticide residues are common rather than exceptional. For example, in a sampling of apples in Washington State, 84% tested positive for pesticides; in some cases, levels were so high that a child consuming half an apple would exceed the daily safe exposure level. In order to reduce pesticide exposure, new strategies need to be developed. Recently protein bodies have been discovered which reversibly occlude phloem cells in case of injury. This type of protein body has only been found to date in bean plants. Using molecular, microscopic, and biochemical methods the mechanism and control of the reaction will be investigated. In addition it will be investigated if similar mechanisms occur in other plant families, and if those mechanisms can be used to induce resistance in plants which have high susceptibility to phloem feeding insects. These new strategies carry the potential to dramatically reduce the amount of insecticides currently required in modern agriculture. Additional broader impacts are expected through training of undergraduate and graduate students on the use of microscopy to study the mechanism of phloem transport and phloem insect interactions