The Arabidopsis chloroplast ribosome recycling factor is essential for embryogenesis and chloroplast biogenesis.
To gain insight into the functions of the nuclear-encoded factors involved in chloroplast development, we characterized the high chlorophyll fluorescence and pale green mutant 108-1 (designated as hfp108-1) of Arabidopsis thaliana. Map-based cloning revealed that the mutant contains a tandem repeat of part of the sequence (including 116 nucleotides from 631 to 746 bp downstream of the ATG) of At3g63190, which encodes a chloroplast ribosome recycling factor homologue and was named AtcpRRF. The chloroplasts of hfp108-1 plants contain few internal thylakoid membranes and are severely defective in the accumulation of chloroplast-encoded proteins. In vivo labeling experiments showed a drastic decrease in the synthesis of the chloroplast-encoded proteins, which may be attributed primarily to reduced translation of the corresponding mRNA molecules. The level of the HFP108 transcript was greatly reduced in hfp108-1, so hfp108-1 showed a weak phenotype, and null alleles of HFP108 (hfp108-2) were embryonic lethal. Observations with cleared seeds in the same silique showed that homozygous hfp108-2 seeds were blocked at the heart stage and did not develop further. Thus, these results suggest that AtcpRRF is essential for embryogenesis and chloroplast biogenesis.
Wang
Liyuan
L
Photosynthesis Research Center, Institute of Botany, Chinese Academy of Sciences, Beijing, China.
Ouyang
Min
M
Li
Qiannan
Q
Zou
Meijuan
M
Guo
Jinkui
J
Ma
Jinfang
J
Lu
Congming
C
Zhang
Lixin
L
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000196:embryology* / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D002736:Chloroplasts / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D003001:Cloning, Molecular; D018744:DNA, Plant / Q000235:genetics; D017343:Genes, Plant; D046529:Microscopy, Electron, Transmission; D008969:Molecular Sequence Data; D009154:Mutation; D030821:Plants, Genetically Modified; D012269:Ribosomal Proteins / Q000235:genetics / Q000378:metabolism*; D012270:Ribosomes / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D020080:Tandem Repeat Sequences
D029681:Arabidopsis Proteins; D018744:DNA, Plant; D012269:Ribosomal Proteins; C087267:ribosome releasing factor