Photosynthesis research: advances through molecular biology – the beginnings, 1975–1980s and on...

Restriction endonuclease recognition sites and genes for rRNAs were first mapped on chloroplast chromosomes in 1975–1976. This marked the beginning of the application of molecular biology tools to photosynthesis research. In the first phase, knowledge about proteins involved in photosynthesis was used to identify plastid and nuclear genes encoding these proteins on cloned segments of DNA. Soon afterwards the DNA sequences of the cloned genes revealed the full primary sequences of the proteins. Knowledge of the primary amino acid sequences provided deeper understanding of the functioning of the protein and interactions among proteins of the photosynthetic apparatus. Later, as chloroplast DNA sequencing proceeded, genes were discovered that encoded proteins that had not been known to be part of the photosynthetic apparatus. This more complete knowledge of the composition of reaction centers and of the primary amino acid sequences of individual proteins comprising the reaction centers opened the way to determining the three-dimensional structures of reaction centers. At present, the availability of cloned genes, knowledge of the gene sequences and systems developed to genetically manipulate photosynthetic organisms is permitting experimental inquiries to be made into crucial details of the photosynthetic process. This revised version was published online in August 2006 with corrections to the Cover Date.     

History of chloroplast genomics

The presence of chloroplast DNA was established in 1963. With the development of recombinant DNA technologies, chloroplast DNA was selected as one of the first candidates for genome sequencing. The first physical map was reported for maize chloroplasts in 1976. As tobacco has been popular as an experimental system, tobacco chloroplast DNA has been extensively analyzed and the complete nucleotide sequence was established in 1986. This sequencing and the availability of tobacco chloroplast transformation techniques and of in vitro expression systems have formed the basis of an ongoing functional genomics program. This revised version was published online in August 2006 with corrections to the Cover Date.