Have invasive rhizobia escaped their bacteriophage enemies? And, how important are phages to rhizobial ecology?
Ellen Simms, Professor
Integrative Biology
Applications for Fall 2024 are closed for this project.
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 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 first asked: Are introduced rhizobia immune to phages that attack native rhizobia? If so, then introduced rhizobia might also enjoy enemy escape. However, European phages might also have been co-introduced into new habitats. Due to this possibility, we are also asking: Are the phages that attack introduced rhizobia more closely related to European phages or native California phages? We will be able to answer this question when we obtain genome sequences of our phages, which are being sequenced by the Joint Genome Institute. Finally, we are conducting experiments to ask whether introduced rhizobia are less often attacked by phages collected from European rhizobia than phages collected from native rhizobia.
Role: With guidance and support from the project supervisor, you will participate in experimental design, bacterial culturing, amplifying 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 and amplification, and proper data management techniques.
There are ample opportunities for independent projects for students who demonstrate dedication and/or plan to stay on for multiple semesters.
Qualifications: 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 definite plus. Applicants with a genuine interest in biology will be favored. We prefer that you be at least a sophomore in a Biological Science major.
Day-to-day supervisor for this project: Ellen L Simms
Hours: to be negotiated
Related website: http://www.simmslab.org/
Biological & Health Sciences