Comparison of the nucleotide sequences of ferredoxin-cDNAs among some Datura plants.

The nucleotide sequences of partial ferredoxin (Fd)-cDNAs (corresponding to the amino acid sequence of 22-87 in the total 97 amino acids of ferredoxin) were determined for Datura arborea, D. stramonium, D. metel, and related Datura plants. Non-synonymous substitutions were noted at 4 positions and a synonymous substitution was seen at position 82 (Gln [CAA] (arborea) vs. Gln [CAG] (stramonium and metel)). The nucleotide sequence of Fd-cDNA may provide more detailed information regarding the relative taxonomic positions of plants than the amino acid sequence. However, Datura plants in the same section (metel, fastuosa, and innoxia) and of different varieties (stramonium var. stramonium and stramonium var. tatula) showed identical Fd-cDNA nucleotide sequences. This result suggests that there are very close relationships among the plants in each group.