Principal Investigator Sallie Chisholm
Phage are an integral part of the Prochlorococcus system and we have isolated hundreds of phage that infect Prochlorococcus from broad regions of the world oceans, and have a growing number of phage genome sequences. All genomes examined thus far encode, transcribe, and translate ancillary metabolic genes acquired from host cells -- including photosynthesis genes. It appears that these genes are maintained by selection in the phage, and function to increase phage fitness by augmenting bottlenecks in host metabolism during infection. At the same time they serve as an expanded reservoir of host genes in the global ocean, that is under a different set of selective pressures than their host-bound homologs.
To help develop Prochlorococcus as a model system, we have built a web site -- a “Prochlorococcus Portal” -- that hosts genomic, transcriptomic, and proteomic data available for Prochlorocccus and its phage.