Plastocyanin is indispensable for photosynthetic electron flow in Arabidopsis thaliana.
Plastocyanin is a soluble copper-containing protein present in the thylakoid lumen, which transfers electrons to photosystem I. In the chloroplast of the flowering plant Arabidopsis thaliana, a cytochrome c6-like protein is present, which was recently suggested to function as an alternative electron carrier to plastocyanin. We show that Arabidopsis plants mutated in both of the two plastocyanin-coding genes and with a functional cytochrome c6 cannot grow photoautotrophically because of a complete block in light-driven electron transport. Even increased dosage of the gene encoding the cytochrome c6-like protein cannot complement the double mutant phenotype. This demonstrates that in Arabidopsis only plastocyanin can donate electrons to photosystem I in vivo.
Weigel
Martin
M
Abteilung für Pflanzenzüchtung und Ertragsphysiologie, Max-Planck-Institut für Züchtungsforschung, Carl-von-Linné-Weg 10, D-50829 Köln, Germany.
Varotto
Claudio
C
Pesaresi
Paolo
P
Finazzi
Giovanni
G
Rappaport
Fabrice
F
Salamini
Francesco
F
Leister
Dario
D
D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D004251:DNA Transposable Elements; D004579:Electron Transport; D016296:Mutagenesis; D010788:Photosynthesis / Q000502:physiology*; D045322:Photosynthetic Reaction Center Complex Proteins / Q000378:metabolism; D045331:Photosystem I Protein Complex; D010802:Phylogeny; D010970:Plastocyanin / Q000235:genetics / Q000378:metabolism*
D004251:DNA Transposable Elements; D045322:Photosynthetic Reaction Center Complex Proteins; D045331:Photosystem I Protein Complex; D010970:Plastocyanin