Jannick Van Cauwenberghe


IB department at UC Berkeley


phages, rhizobia, host range, biogeography, invasion biology

Project Description

Introduced plants can become invasive when they escape the insect and microbial enemies that control native plant populations. Legumes benefit from symbiotic relationships with nitrogen-fixing bacteria called rhizobia, which colonize nodules in legume roots. We have found that three invasive leguminous plant species (French broom, Spanish broom, and Scotch broom) host rhizobia more closely related to European rhizobia than to California rhizobia, which suggests that European rhizobia may have co-invaded California with their legume hosts. Invasion theory predicts that invasive species might proliferate in a novel habitat if they have escaped the natural enemies that control their populations in their native range. Bacteriophages (phages, for short) are viruses that attack bacteria and can control bacterial population densities. In this project, we ask if introduced rhizobia are less often attacked by phages than are native rhizobia. If so, then introduced rhizobia might also enjoy enemy escape. With guidance and support from the project supervisor, you will participate in experimental design, culturing bacteria, isolating and characterizing bacteriophages, and collecting and analyzing data. Over the course of the semester, you may learn sterile technique, initiation and maintenance of bacterial cultures, phage isolation, DNA extraction and handling, and proper data management techniques.


You must have a strong work ethic and an interest in microbiology and ecology. You must be dedicated to learning from and contributing to the project, which involves meticulous laboratory procedures, attention to detail, continuous care of bacteria, and sometimes boring and repetitive protocols, but exciting and rewarding results. Experience with sterile technique and bacterial culturing is a plus, but not required. Applicants with a genuine interest in biology will be favored.

Expected time commitment

about 9-10 hours per week

Preferred start time: