A novel site for streptomycin resistance in the "530 loop" of chloroplast 16S ribosomal RNA.

The chloroplast gene for 16S rRNA was cloned from two maternally inherited streptomycin-resistant mutants ofNicotiana differing in degree of resistance at the whole plant and isolated chloroplast level. A single-nucleotide change in the 16S rRNA gene was detected for each mutant: a C to T transition at nucleotide 860 (Escherichia coli coordinate C912) which is an often mutated site, and a novel transition of C to T at nucleotide 472 (E. coli coordinate C525). The novel mutation is located in the phylogenetically conserved "530 loop".