The phloem of higher plants is a long distance translocation system that distributes assimilates generated by photosynthesis to tissues such as fruits and underground organs. The majority of the nutrients consumed by humans have been translocated through the phloem. In addition, the phloem serves as a long distance signaling system. It can roughly be compared to a combination of the human circulatory and nervous system. Due to its high concentration of sugars and other nutrients, it represents the primary target for pests such as aphids, mealybugs, and leafhoppers. Furthermore, plant viruses use the phloem to spread throughout the plant. This causes substantial economic damage and leads to the use of high amounts of protective chemicals. Despite the central role the phloem plays in plant pest interactions, the current knowledge of the underlying processes is poor. By employing newly-developed molecular and cell biological tools, this project aims to elucidate cellular and subcellular processes in phloem transport, signaling, and plant-pest interactions. One long-term outcome will be the provision of a scientific basis for new strategies to protect plants from pest infestation. These new strategies carry the potential to dramatically reduce the amount of insecticides currently required in modern agriculture. In addition, broader impacts include education through teaching and textbook information on the mechanism of phloem transport and phloem insect interactions and through training of undergraduate and graduate students.
