Sensory evaluation of transgenic Solanum tuberosum producing r-thaumatin II

Abstract

Agrobacterium rhizogenes A4T and the shuttle vectorp WIT2 were used to transform Solanum tuberosum cv. iwa with a CaMV35S5'-thaumatin II- tm/3' chimaeric gene. Biologically active r-thaumatin was produced in the transgenic plants inducing a sweet-taste phenotype. This is in contrast to expression of thaumatin chimaeras in Escherichia coli, Bacillus subtilis, Streptomyces lividans, Saccharomyces cerevisiae, and Kluyveromyces lactis by previous workers where no change of phenotype was detected. This work successfully combines the sweet flavour phenotype of Thaumatococcus daniellii, a plant difficult to cultivate, with a high-yielding temperate crop plant. The CaMV35S'-preprothaumatin II-tm/3' chimaera may be thought of as a palatability gene of possible commercial importance.

Keywords:

• thaumatin
• transgenic
• Solanum tuberosum
• Agrobacterium rhizogenes
• biologically active