PARENT SESSION

Symposium S7B Evolution of photosynthesis
Thursday September 2nd, 2004 2:40 PM-4:40 PM Room 511D
Chair: Beverley Green
Co-Chair: Bob Blankenship

Evolution of chlorophyll antenna complexes in Acaryochloris and Prochlorophytes. Min Chen^*,, Roger Hiller, Christopher Howe, Anthony Larkum¹, ¹ School of Biological Sciences, Sydney, NSW, Australia

ABSTRACT- Two genes for light-harvesting chlorophyll-binding proteins have been cloned from genomic DNA from the chlorophyll d-containing Acaryochloris marina and two fom the chlorophyll b-containing Prochloron didemni. These genes are homologous with the pcb genes of those cyanaobacteria that possess chlorophyll b ("prochlorophytes"). They also show strong similarity to the isiA genes of cyanobacteria and CP 43 of photosystem II. Phylogenetic tree reconstruction methods have been used to assess the evolutionary relationships of the various genes. The Prochlorococcus species have clearly evolved several light-harvesting strategies involving various pcb genes. However, in the prochlorophytes, Prochlorothrix hollandica and Prochloron didemni and in Acaryochloris marina there is a strong similarity in both sequence structure and gene organization. The results can be interpreted most easily in terms of lateral transfer of these genes in a number of the organisms.

KEY WORDS: phylogenetic trees, prochlorophytes, pcb genes, Acaryochloris