Disruption of the Arabidopsis photosystem I gene psaE1 affects photosynthesis and impairs growth.
The psae1-1 mutant of Arabidopsis was identified on the basis of a decrease in the effective quantum yield of photosystem II, among a collection of plants subjected to transposon tagging with the Enhancer element. The steady-state redox level and the rate of re-oxidation of P700 are significantly altered in psae1-1 mutants. The responsible mutation was localised to psaE1, one of two Arabidopsis genes that encode subunit E of photosystem I. An additional mutant allele, psae1-2, was identified by reverse genetics. In wild-type plants, the psaE1 transcript is expressed at a higher level than psaE2 mRNA. In the mutants, however, the E1 transcript was barely detectable, and was expressed only in small groups of wild-type cells resulting from somatic reversions. As a consequence, the amount of PsaE protein present in the mutant is significantly reduced. Concomitantly, the levels of other stromal photosystem I subunits (PsaC and PsaD) are also affected. Mutant plants showed a marked increase in light sensitivity and photoinhibition. Additional effects of the psae1 mutation include light green pigmentation, an increase in chlorophyll fluorescence and a decrease of approximately 50% in growth rate under greenhouse conditions.
Varotto
C
C
Zentrum zur Identifikation von Genfunktionen durch Insertionsmutagenese bei Arabidopsis thaliana (ZIGIA), Max-Planck-Institut für Züchtungsforschung, Carl von Linné Weg 10, 50829 Köln, Germany.
Pesaresi
P
P
Meurer
J
J
Oelmüller
R
R
Steiner-Lange
S
S
Salamini
F
F
Leister
D
D
D000483:Alleles; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D029681:Arabidopsis Proteins; D001483:Base Sequence; D004251:DNA Transposable Elements; D045342:Light-Harvesting Protein Complexes; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D010084:Oxidation-Reduction; D010788:Photosynthesis / Q000235:genetics*; D045322:Photosynthetic Reaction Center Complex Proteins / Q000235:genetics* / Q000378:metabolism; D045331:Photosystem I Protein Complex; D045332:Photosystem II Protein Complex; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA
D029681:Arabidopsis Proteins; D004251:DNA Transposable Elements; D045342:Light-Harvesting Protein Complexes; D045322:Photosynthetic Reaction Center Complex Proteins; D045331:Photosystem I Protein Complex; D045332:Photosystem II Protein Complex; C412446:psaE1 protein, Arabidopsis