Ribosomal protein S12 as a site for streptomycin resistance in Nicotiana chloroplasts

Summary A streptomycin resistant Nicotiana plastome mutant, X/str^R6, was subjected to molecular analysis. In this mutant, a single nucleotide transition, C » T, in the chloroplast gene for ribosomal protein S12 alters codon 90 from proline to serine while the nucleotide sequence of the chloroplast 16 S rRNA gene is identical to that of the wild type. Mutant X/str^R6 thus differs from several previously reported streptomycin resistant chloroplast mutants which are altered in the gene for 16 S rRNA.