Emiliania huxleyi, a model coccolithophore, plays a critical role in the chemical and ecological composition of marine ecosystems. A significant part of biogeochemical cycles, E. huxleyi is a sink for carbon in the marine habitat and contributes to the marine paleobotanic record. Ecologically, the coccolithophore is a key part of marine systems, as it forms expansive blooms, which can restructure the marine environment and serve as habitats to a range of other microbial organisms, including viruses and bacteria.

Phaeobacter inhibens is a Roseobactereaceae, a group of marine α-proteobacteria commonly found associated to marine algae, effecting the coccolithophore’s health and survival in a Jekyll and Hyde relationship mirroring its pattern of a bloom-bust life cycle. The nature of the relationship between P. inhibens and E. huxleyi is both symbiotic and pathogenic, with the bacterium selectively killing the diploid calcifying and haploid flagellated strains of E. huxleyi, causing apoptotic like-programmed cell death (AL-PCD).

Current research at the Case Lab focuses on:

• elucidating the mechanisms and molecules behind the cell type selective killing of E. huxleyi by its bacterial symbiont and pathogen, P. inhibens

• using dual species transcriptomics to identify mechanistic indicators in host and pathogen

• elucidating the signaling and functional roles of lignin and its derivatives in the complex P. inhibens - E. huxleyi interaction