Homologous comparisons of photosynthetic system I genes among cyanobacteria and chloroplasts.
It has now believed that chloroplasts arose from cyanobacteria, however, during endosymbiosis, the photosynthetic genes in chloroplasts have been reduced. How these changes occurred during plant evolution was the focus of the present study. Beginning with photosystem I (PSI) genes, a homologous comparison of amino acid sequences of 18 subunits of PSI from 10 species of cyanobacteria, chloroplasts in 12 species of eucaryotic algae, and 28 species of plants (including bryophytes, pteridophytes, gymnospermae, dicotyledon and monocotyledon) was undertaken. The data showed that 18 genes of PSI can be divided into two groups: Part I including seven genes (psaA, psaB, psaC, psaI, psaJ, ycf3 and ycf4) shared both by cyanobacteria and plant chloroplasts; Part II containing another 11 genes (psaD, psaE, psaF, psaK, psaL, psaM, btpA, ycf37, psaG, psaH and psaN) appeared to have diversified in different plant groups. Among Part I genes, psaC, psaA and psaB had higher homology in all species of cyanobacteria and chloroplasts. Among Part II genes, only psaG, psaH and psaN emerged in seed plants.
Yu
Jie
J
School of Marin Science & Engineering, Tianjin University of Science & Technology, Tianjin 300457, China.
Ma
Pei-Jun
PJ
Shi
Ding-Ji
DJ
Li
Shi-Ming
SM
Wang
Chang-Lu
CL
D002736:Chloroplasts / Q000235:genetics*; D000458:Cyanobacteria / Q000235:genetics*; D056890:Eukaryota / Q000235:genetics; D005057:Eukaryotic Cells / Q000378:metabolism; D005798:Genes, Bacterial; D017343:Genes, Plant; D045331:Photosystem I Protein Complex / Q000235:genetics* / Q000378:metabolism; D010802:Phylogeny; D010944:Plants / Q000235:genetics; D012689:Sequence Homology, Nucleic Acid; D046939:Synechocystis / Q000235:genetics
D045331:Photosystem I Protein Complex