All organisms must sense, integrate, and respond to information from their external environment. Whether this information concerns the presence of food, a change in temperature, or the approach of a predator, organisms need to assess their surroundings and carry out appropriate actions. For cells within a developing organism, it is likewise important to assess information coming from other cells. For example, cell-cell signals are important for controlling the emergence of form and function. Finally, information is critical during the interactions of multicellular organisms with microbes.
Many biological signals are in chemical form.
Our research is concerned with chemical signals that control the interaction of a bacterium with a multicell host organism. These organisms can grow in isolation from each other, but when brought together they cooperate to produce a tumorous growth called a root nodule. Inside the nodule, the bacteria establish a colony that feeds nutrients to the plant. The bacterium-plant association is considered a symbiosis because it provides benefits to each partner. Also, the interaction is species specific, as bacteria only form symbiotic root nodules on certain plants and not others.