Kay Bidle, Ph.D.

Molecular and cellular mechanisms that shape the success of microbes in the oceans

Research that focuses on the molecular and cellular mechanisms that regulate microbial responses to biotic (viruses) and abiotic (nutrient, light) stresses in the oceans, ultimately, shaping their ecological success and collective biogeochemical influence on the oceans.

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Research Description

My work has placed particular emphasis on cellular ‘arms races’ and how they mechanistically regulate phytoplankton mortality and bloom termination, taking aim at a long-held misconception in oceanography that phytoplankton are immortal unless eaten by zooplankton or removed by sinking into the deep ocean. Although phytoplankton represent <1% of global biomass, they account for ~50% of global primary productivity, meaning, on average, they grow, die and are replaced weekly. My research program employs a variety of genome-enabled physiological, biochemical, and genetic techniques to provide a novel, comprehensive mechanistic understanding of stress and programmed cell death (PCD) pathways in marine phytoplankton. Our work targets the sensing, activation, and regulation of PCD pathways, how they evolved in diverse unicellular phytoplankton, how it mechanistically interfaces with stress and virus infection pathways across a mandala of different niches and host-virus systems, how stress signals are sensed and transduced into cellular responses, and how these cellular responses manifest on a large scale to influence elemental cycles in the oceans.

Research Impact

My research activities will elucidate fundamental principles in microbial oceanography that govern how marine microbes interact with and respond to each other and their chemical environments. This includes dissolved ‘infochemicals’ that are produced in response to different stresses and function as an informational language that influences the physiological responses of neighboring cells. Because they are also often linked to specific cellular processes and physiological states, these infochemicals can function as novel, diagnostic biomarkers to elucidate microbe-environment sensing, response pathways, and cell fate in the oceans. Our efforts aim to understand small-scale microbial interactions at the levels of cell-virus, cell-environment, and cell-infochemical signals and determine how they impact ecosystem dynamics, nutrient flux, and upper ocean biogeochemistry. We are particularly interested in their connection to phytoplankton-virus arms races that rage at sea. Using ecologically relevant host-virus systems for diatoms and coccolithophores, we are interrogating how viruses interact with and control their microbial hosts and how PCD pathways are a widespread and a conserved component of algal-virus co-evolutionary arms races. Central to this process are mechanisms of resistance and innate immunity and their interface with PCD pathway regulation. Ultimately, we aim to elucidate how these interactions structure and imprint ocean biogeochemistry by understanding how cornerstone infochemical molecules, which facilitate viral infection and/or PCD on massive scales, mechanistically ‘lubricate’ upper ocean biogeochemistry. To that end, our research couples these diagnostic biomarkers of stress, virus infection and PCD with oceanographic measurements in order to quantify how viral infection and nutrient stress influences cell fate and the cycles of carbon, nitrogen and sulfur. We are using these biomarkers to better integrate viruses into the oceanic carbon cycle and trace the flow and fate of virally derived carbon. We are also working to layer these novel analytical proxies of cellular response mechanisms onto a larger conceptual framework of ecosystem response by integrating novel biomarkers onto remote observational platforms.

Papers

Kendrick, B.J., G.R. DiTullio, T.J. Cyronak, P.A. Lee, J.M. Fulton, B.A.S. Van Mooy, K.D. Bidle. Temperature-induced viral resistance in Emiliania huxleyi (Prymnesiophyceae) PLoS One (in press).

Bidle, K.D. Elucidating marine virus ecology through a unified heartbeat. Proc. Natl. Acad. Sci. USA (doi: 10.1073/pnas.1417243111; 27 October 2014 Early Edition issue).

Bidle, K.D. The molecular ecophysiology of programmed cell death in marine phytoplankton. 2015. Annu. Rev. Mar. Sci., 7 (in press).

Brown, C.M., and K.D. Bidle. 2014. Attenuation of virus production at high multiplicities of infection in Aureococcus anophagefferens. Virology 466-467: 71-81(http://dx.doi.org/10.1016/j.virol.2014.07.023).

Moniruzzaman, M., G.R. LeCleir, C.M. Brown, C.J. Gobler, K.D. Bidle, W.H. Wilson, and S.W. Wilhelm. 2014. Genome of Brown Tide virus (AaV), the little giant of the Megaviridae, elucidates NCLDV genome expansion and host-virus coevolution Virology 466-467: 60-70 (http://dx.doi.org/10.1016/j.virol.2014.06.031).

Kustka, A.B., A. Milligan, A. New, C. Gates, H. Zheng, K.D. Bidle, and J. Rienfelder. 2014. Low CO₂ results in a rearrangement of carbon metabolism to support C4 photosynthetic carbon assimilation in two marine diatoms. New Phytologist. (doi: 10.1111/nph.12926).

Lehahn, Y., I. Koren, D. Schatz, M. Frada, U. Sheyn, E. Boss, S. Efrati, Y. Rudich, M. Trainic, S. Sharoni, C. Laber, G.R. DiTullio, M.J.L. Coolen, A.M. Martins, B.A.S. Van Mooy, K.D. Bidle, and A. Vardi. 2014. Decoupling physical from biological processes to assess the impact of viruses on a mesoscale algal bloom. Current Biology 24: 2041-2046.

Lehahn, Y., I. Koren, Y. Rudich, K.D. Bidle, M. Trainic, J.M. Flores, S. Sharoni, A. Vardi. 2014. Decoupling atmospheric and oceanic factors affecting aerosol loading over a cluster of mesoscale North Atlantic eddies. Geophys. Res. Lett. 41(11): 4075-4081.

Keeling, P.J., et al (total of 77 authors). 2014. The Marine Microbial Eukaryote Transcriptome Sequencing Project (MMETSP): Illuminating the functional diversity of eukaryotic life in the oceans through transcriptome sequencing. PLoS Biology 12(6): e1001889.

Ray, J.L., L. Haramaty, R. Thyrhaug, H. Fredricks, B. Van Mooy, A. Larsen, K.D. Bidle, and R.-A. Sandaa. 2014. Virus infection of Haptolina ericina and Phaeocystis pouchetii suggests evolutionary conservation of programmed cell death induction in marine haptophyte-virus interactions. J. Plankton Res. (doi: 10.1093/plankt/fbu029).

Rose, S.L., J. Fulton, C.M. Brown, F. Natale, B.A.S. Van Mooy, and K.D. Bidle. 2014. Isolation and characterization of lipid rafts in Emiliania huxleyi: a role for membrane microdomains in host-virus Interactions. Environ. Microbiol. 16(4): 1150–1166.

Fulton, J.M,H.F. Fredricks,K.D. Bidle, A. Vardi, B.J. Kendrick,G.R. DiTullio and B.A.S. Van Mooy. 2014. Novel molecular determinants of viral susceptibility and resistance in the lipidome of Emiliania huxleyi. Environ. Microbiol. 16(4): 1137–1149.

Thamatrakoln, K., B. Bailleul, C.M. Brown, M.Y. Gorbunov, A.B. Kustka, M. Frada, P. Joliot, P.G. Falkowskiand K.D. Bidle. 2013. Death-specific protein in a marine diatom regulates photosynthetic responses to iron and light availability. Proc. Natl. Acad. Sci. USA 10(50): 20123-20128.

Bar-Zeev, E., I. Avishay, K.D. Bidle and I. Berman-Frank. 2013. Programmed cell death in the marine cyanobacterium Trichodesmium mediates carbon and nitrogen export. ISME Journal 7(12): 2340-2348.

Read, B., et al. (total of 73 authors). 2013. Pan genome of the phytoplankton Emiliania underpins its global distribution. Nature. 499:209-213.

Seth-Pasricha, M., K.A. Bidle, and K.D. Bidle. 2013. Specificity of archaeal caspase activity in the extreme halophile Haloferax volcanii. Environ. Microbiol. Reports 5(2): 263-271.

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