A new nitrogen fixing endosymbiont in epithemioid diatoms
Rhopalodia gibba and related Epithemia diatoms contain “spheroid bodies” that are in fact nitrogen-fixing cyanobacterial endosymbionts. Estimated at a mere 12 million years old, spheroid bodies offers unparalleled opportunity to watch endosymbiosis “in action.” Moreover, compared to facultative symbioses for nitrogen fixation in plants, this obligate endosymbiosis is a novel solution only found in aquatic ecosystems. Useful skills: genomics, oceanography, algae culturing.
IN PROGRESS
First genetic screen in model diatom P. tricortum
Microscopic cyanobacteria and algae dominate the 50% of global photosynthesis that occurs in marine and fresh waters, in contrast to multicellular plants that carry out terrestrial photosynthesis. One group of algae, diatoms, alone account for 40% of marine photosynthesis and undergo seasonal blooms critical for carbon sequestration.
IN PROGRESS
Composite fluorescent image of Phaeodactylum tricornutum in its triradiate form showing chlorophyll auto-fluorescence (Red).
An oil-secreting algae, Botyrococcus braunii
Biofuels are an important and underdeveloped component of a renewable energy strategy. Current first-generation biofuels produced from edible crops have a number of indirect consequences that reduce their economic and environmental benefits. Algae are a promising source of next-generation biofuels. The green microalgae Botryococcus braunii has unique advantages as a potential biofuel producer: It biosynthesizes hydrocarbons that are readily converted into petroleum-equivalent fuels and stores these hydrocarbons in extracellular space where they are more readily extracted, addressing two energy-intensive and costly steps in biofuels production. We propose to identify the genes required for hydrocarbon biosynthesis and export in B. braunii, develop methods to genetically modify B. braunii to optimize its growth and/or hydrocarbon production, and introduce its hydrocarbon biosynthetic and export genes into heterologous organisms. This high-risk, high-reward project has the ultimate goal of genetically engineering B. braunii or heterologous organisms modified with B. braunii genes as optimized producer strains for next-generation biofuel production.