Polymerase chain reaction comparison of the gene for strictosidine synthase from ten Rauvolfia species.

The gene for strictosidine synthase, str1, has been analyzed by the polymerase chain reaction in ten species of Rauvolfia, the origins of which span the tropical belt: R. cambodiana (Indochina), R. canescens (India), R. chinensis (China), R. heterophylla (Central America), R. mannii (West Africa), R. nitida (West Indies), R. praecox (Brasil), R. serpentina (India), R. sumatrana (Indonesia) and R. verticillata (Indochina). Restriction endonuclease analysis of the gene fragments produced with genomic DNA from each of the ten species as template revealed that str1 is highly conserved in the Rauvolfia species investigated. These results suggest that there is a stringent selection pressure on the gene for this key enzyme of indole alkaloid biosynthesis.