Mutualistic interactions between plants and microorganisms and consequences of such relationships for ecosystems are noted as paradigms of symbiotic interactions in undergraduate ecology and microbiology textbooks. In our experience, these plant-microbe associations are infrequently studied in the undergraduate ecology and microbiology laboratory, possibly due to constraints of time and lack of technical expertise outside of the instructors’ primary fields of study. We first developed a cross-disciplinary project, in Fall 2006, in which students enrolled in general ecology collaborated with students enrolled in applied environmental microbiology to design and execute an experiment using the mutualistic relationship between soybeans and Rhizobium sp. as a model system. During the Fall 2007 semester, students from both classes attended a common meeting in which the instructors described the nature of the project, the need for small groups of students to design and conduct experiments, and to measure the whole plant and microbial responses to treatments. Students collaborated in analysis of results and presentation of their research in a poster session attended by students and instructors. Each student group had at least one ecology student and three microbiology students; the ecology student was to assume responsibility for study of plant growth while the microbiology students were to evaluate Rhizobium abundance. All students collaborated on interpretation of the results of treatments on plants and Rhizobium.
In Fall 2007, the collaboration between two courses led to twenty three student-designed and executed projects on plant-microbe interactions. The poster session involved students presenting during their normally scheduled laboratory periods during the final week of the semester; thus, there were three poster sessions for microbiology students and one for ecology students. During the poster sessions, each student interviewed presenters of three posters and responded in writing to questions about what they’d learned from the poster; every student was interviewed by one or both of the course instructors. Students in research groups that conducted projects and prepared posters judged by instructors to be very good to excellent were invited to attend a regional science meeting during the spring. Instructors offered constructive criticism for revisions to posters and several student groups chose to participate in the regional meeting. Student evaluations of projects and the cross-disciplinary collaboration have provided us with useful ideas concerning organization and communication with students to improve this project in future years.