Abstract
In chloroplast, many characteristics of the gene expression system resemble those of bacteria because chloroplast has an evolutionally prokaryotic origin. To characterize the molecular mechanism of gene expression in chloroplast, we screened several Arabidopsis mutants for chloroplast RNases homologous to bacterial ones from the SALK institute and identified three putative RNase mutants (RNase E, PNPase or RNase II/R) with defect in chloroplast. RNA gel blot analysis confirmed the disrupted expression of the corresponding genes by the T-DNA insertion in these mutants. We also determined that each phenotype of mutants was single, recessive and linked with antibiotic resistance, indicating that the mutant phenotype was derived from the disruption of corresponding genes. We report here more detailed characterization of a putative chloroplastic RNase E mutant, which showed pale-green leaves, retarded growth and significantly reduced photosynthetic activities. Modification of RNA metabolism in the mutant was suggested by RNA blot analysis of plastid-encoded genes.
