Abstract
Chlorophyll metabolism has been studied with various organisms and almost all of the chlorophyll biosynthetic genes have been identified in higher plants. However, only the gene for 3, 8-divinyl protochlorophyllide a 8-vinyl reductase (DVR), which is indispensable for monovinyl chlorophyll synthesis has not been identified yet.
In this study, we isolated an Arabidopsis thaliana mutant that accumulated divinyl chlorophyll instead of monovinyl chlorophyll by ethyl-methanesulfonate mutagenesis. We identified the gene by Map-based cloning of this mutant. The mutant phenotype was complemented by the transformation with the wild-type gene. A recombinant protein encoded by the identified gene was expressed in E. coli and found to catalyze the conversion of divinyl chlorophyllide to monovinyl chlorophyllide, thereby demonstrating that the gene encodes a functional DVR.
Further, identification of the DVR gene helped understanding the evolution of Prochlorococcus marinus, a marine cyanobacteria that is unique in using divinyl chlorophylls.
