2026 Undergraduate Research Showcase

Contrasting Substrate Use by Two Bacterial Species from Pitcher Plant Pools

Document Type

Student Presentation

Presentation Date

4-24-2026

Faculty Sponsor

Dr. Leonora Bittleston and Fiona Harrigian

Abstract

Microbes interact with each other either directly or indirectly, and this can affect their coexistence within a community. Bacteria get their nutrients from various carbon substrates. They use these to power their metabolism, which produces energy for their cellular processes. If multiple bacteria share the same carbon substrate, they will compete for those nutrients, and one will likely win. The bacteria will then not be able to coexist, which will lead to less diverse microbial communities. In our research, we started with different bacterial species originally isolated from the aquatic pools of Sarracenia purpurea carnivorous pitcher plants. We focused on two species, a Pedobacter (ASV2) and a Chromobacterium (ASV5) which have very different impacts on a Tetrahymena species, a protozoan that feeds on bacteria. The Pedobacter supports protozoan growth, while the Chromobacterium inhibits it. Our goal was to measure how the two bacterial species use different carbon substrates in order to inform their interactions and their likely effects on the broader community. We used Biolog EcoPlates to accomplish this, which contain 31 different carbon substrates that the bacteria may be able to utilize. These plates will allow us to determine which carbon sources each bacteria prefers, if any. Our results found that the Pedobacter ASV2 and Chromobacterium ASV5 species preferred different substrates, with Pedobacter ASV2 using a wide variety while Chromobacterium ASV5 specialized on one in particular. This tells us that these two bacteria will most likely not compete for resources in a broader community setting when they have access to diverse resources. The bacterium that is beneficial for the protozoan predator, Pedobacter ASV2, appears to be able to grow well on many substrates and thus might do better across different conditions.

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