Abstract：
In the past decades, there has been rapid accumulation of genomic sequencing of marine phytoplankton, primarily cyanobacteria and unicellular eukaryotic algae. This unprecedented plethora of sequence information has provided new opportunities and tools in studying the origin and evolution of marine phytoplankton, as well as their prominent role in shaping Earth’s biogeochemical cycles.
In the work presented here, Tuo Shi exploited the full power of genome sequencing to investigate the mode and tempo of genome evolution in cyanobacteria. This work demonstrated that the evolution of cyanobacteria is constrained by the tight molecular interactions between pigments, proteins and lipids, which has left its imprint in a set of highly conserved genes over billions of years of evolution. In effect, these core proteins have become 'frozen metabolic accidents', that is, the metabolic functions these proteins mediate cannot be significantly altered via selection, and hence, are less subject to lateral gene transfer. Using marine diazotrophic (N2-fixing) cyanobacteria as a model organism, Tuo Shi further characterized marine phytoplankton response to environmental perturbations, through a test of “iron hypothesis” in the filamentous Trichodesmium erythraeum IMS101, and microarray-based whole-genome expression profiling in the unicellular Crocosphaera watsonii WH8501. These genome-enabled systematic approaches provided direct experimental evidence of molecular mechanisms that mediate iron acclimation and the segregation of oxygenic photosynthesis and nitrogen fixation (which is sensitive to oxygen).
In the later part of his presentation, Tuo Shi demonstrated employing high-throughput next generation sequencing and genetic engineering technologies to direct research on the applied side of phytoplankton biology, particularly development of renewable biofuels and green chemistry projects and on the discovery of traits that improve biomass yield and productivity.
Finally, Tuo Shi discussed my future research with primary focuses on: 1) (meta)-transcriptomics study of marine dinoflagellates; 2) development of cDNA microarray for assessing transcription in marine dinoflagellates; 3) phytoplankton genomics; and 4) algal biofuels.
