A POINT MUTATION IN THE CHLOROPLAST RPS12 GENE FROM NICOTIANA-PLUMBAGINIFOLIA CONFERS STREPTOMYCIN RESISTANCE

In an effort to understand the mechanism of streptomycin resistance in Nicotiana plumbaginifolia, we have sequenced the chloroplast rps12 ge ne, a potential molecular target. We report that a streptomycin-resist ant mutant isolated from protoplast cultures of N. plumbaginifolia con tains an A-to-G transition at nucleotide position 149 in exon 2 of the chloroplast rps12 gene. The detected point mutation predicts a substi tution of arginine for lysine in a phylogenetically conserved region.