RRC ID 47725
Author Yoo SC, Cho SH, Sugimoto H, Li J, Kusumi K, Koh HJ, Iba K, Paek NC.
Title Rice virescent3 and stripe1 encoding the large and small subunits of ribonucleotide reductase are required for chloroplast biogenesis during early leaf development.
Journal Plant Physiol
Abstract The virescent3 (v3) and stripe1 (st1) mutants in rice (Oryza sativa) produce chlorotic leaves in a growth stage-dependent manner under field conditions. They are temperature-conditional mutants that produce bleached leaves at a constant 20 degrees C or 30 degrees C but almost green leaves under diurnal 30 degrees C/20 degrees C conditions. Here, we show V3 and St1, which encode the large and small subunits of ribonucleotide reductase (RNR), RNRL1, and RNRS1, respectively. RNR regulates the rate of deoxyribonucleotide production for DNA synthesis and repair. RNRL1 and RNRS1 are highly expressed in the shoot base and in young leaves, and the expression of the genes that function in plastid transcription/translation and in photosynthesis is altered in v3 and st1 mutants, indicating that a threshold activity of RNR is required for chloroplast biogenesis in developing leaves. There are additional RNR homologs in rice, RNRL2 and RNRS2, and eukaryotic RNRs comprise alpha(2)beta(2) heterodimers. In yeast, RNRL1 interacts with RNRS1 (RNRL1:RNRS1) and RNRL2:RNRS2, but no interaction occurs between other combinations of the large and small subunits. The interacting activities are RNRL1:RNRS1 > RNRL1:rnrs1(st1) > rnrl1(v3):RNRS1 > rnrl1(v3):rnrs1(st1), which correlate with the degree of chlorosis for each genotype. This suggests that missense mutations in rnrl1(v3) and rnrs1(st1) attenuate the first alphabeta dimerization. Moreover, wild-type plants exposed to a low concentration of an RNR inhibitor, hydroxyurea, produce chlorotic leaves without growth retardation, reminiscent of v3 and st1 mutants. We thus propose that upon insufficient activity of RNR, plastid DNA synthesis is preferentially arrested to allow nuclear genome replication in developing leaves, leading to continuous plant growth.
Volume 150(1)
Pages 388-401
Published 2009-5
DOI 10.1104/pp.109.136648
PII pp.109.136648
PMID 19297585
PMC PMC2675711
MeSH Cell Division Chloroplasts / drug effects Chloroplasts / metabolism* Chromosome Mapping Chromosomes, Plant Cloning, Molecular Gene Expression Profiling Genetic Complementation Test Hydroxyurea / pharmacology Mutation Oryza / drug effects Oryza / genetics Oryza / growth & development* Oryza / metabolism Phenotype Plant Leaves / drug effects Plant Leaves / genetics Plant Leaves / growth & development Plant Leaves / metabolism Plant Proteins / genetics Plant Proteins / metabolism Plant Proteins / physiology* Protein Subunits / genetics Protein Subunits / metabolism Protein Subunits / physiology Ribonucleotide Reductases / genetics Ribonucleotide Reductases / metabolism Ribonucleotide Reductases / physiology*
IF 6.305
Times Cited 110
Rice 標識遺伝子系統