Poster: Photosynthesis

Abs # 369: Functional genomics of photosynthesis using Chlamydomonas reinhardtii

Presenter:	Dent, Rachel M., racheld@uclink4.berkeley.edu
Authors	Dent, Rachel M. (A)   Kobayashi, Marilyn  (A)   Niyogi, Krishna K. (A)
Affiliations:	(A): U.C. Berkeley

Chlamydomonas reinhardtii represents a unique system for the study of photosynthetic and photoprotective processes. This alga offers several advantages over other photosynthetic model organisms for the isolation of genes involved in photosynthesis, and the elucidation of how these genes function and interact with one another. Using a functional genomic approach, our long term goal is to isolate mutants in every gene involved in photosynthesis and photoprotection. To achieve this aim we are utilizing a combination of forward and reverse genetic approaches. Here, we report on the progress of the forward genetics project. In an effort to saturate the genome, we propose generating 96,000 insertional mutants in Chlamydomonas and subjecting these to a number of phenotypic screens. At this early stage of the project, a bank of 8,000 insertional mutants has been generated and screened to identify mutants that are pigment deficient, light sensitive, non-photosynthetic, or hypersensitive to reactive oxygen species. This represents approximately 300 mutants. Flanking DNA is being isolated from these mutants using TAIL-PCR or genome walking. Additionally, a new method of Universal Fast Walking (UFW) is being tested for a higher-throughput approach to the isolation of flanking sequence. These sequence fragments are used to search the recently sequenced Chlamydomonas genome to locate the point of insertion and identify candidate genes responsible for the mutant phenotype. Ultimately, the position of each of the insertion sites will be marked on the genome sequence and the flanking sequence made available in a searchable database.