Characterization of the Arabidopsis thaliana mutant pcb2 which accumulates divinyl chlorophylls.
We characterized the pcb2 (pale-green and chlorophyll b reduced 2) mutant. We found through electron microscopic observation that chloroplasts of pcb2 mesophyll cells lacked distinctive grana stacks. High-performance liquid chromatography (HPLC) analysis showed that the pcb2 mutant accumulated divinyl chlorophylls, and the relative amount of divinyl chlorophyll b was remarkably less than that of divinyl chlorophyll a. The responsible gene was mapped in an area of 190 kb length at the upper arm of the 5th chromosome, and comparison of DNA sequences revealed a single nucleotide substitution causing a nonsense mutation in At5g18660. Complementation analysis confirmed that the wild-type of this gene suppressed the phenotypes of the mutation. Antisense transformants of the gene also accumulated divinyl chlorophylls. The genes homologous to At5g18660 are conserved in a broad range of species in the plant kingdom, and have similarity to reductases. Our results suggest that the PCB2 product is divinyl protochlorophyllide 8-vinyl reductase.
Nakanishi
Hiromitsu
H
Division of Gene Research, Department of Life Science, Research Center for Human and Environmental Sciences, Shinshu University, Ueda, 386-8567 Japan.
Nozue
Hatsumi
H
Suzuki
Kenji
K
Kaneko
Yasuko
Y
Taguchi
Goro
G
Hayashida
Nobuaki
N
D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D002734:Chlorophyll / Q000096:biosynthesis*; D002736:Chloroplasts / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure; D002874:Chromosome Mapping; D018389:Codon, Nonsense / Q000235:genetics; D018744:DNA, Plant / Q000235:genetics; D018506:Gene Expression Regulation, Plant / Q000235:genetics*; D018745:Genome, Plant; D046529:Microscopy, Electron, Transmission; D008969:Molecular Sequence Data; D010088:Oxidoreductases / Q000235:genetics* / Q000378:metabolism; D011521:Protochlorophyllide / Q000031:analogs & derivatives* / Q000096:biosynthesis / Q000378:metabolism*; D012333:RNA, Messenger / Q000096:biosynthesis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D013489:Suppression, Genetic / Q000235:genetics
D029681:Arabidopsis Proteins; D018389:Codon, Nonsense; D018744:DNA, Plant; D012333:RNA, Messenger; D002734:Chlorophyll; C020301:2,4-divinylprotochlorophyllide; D011521:Protochlorophyllide; D010088:Oxidoreductases; C502727:PCB2 protein, Arabidopsis