Improved tomatoes produced by modification of polygalacturonase activity.
Poole, N. J.;
International Journal of Food Sciences and Nutrition Year: 1993 Vol: 44 Issue: SUPP 1 Pages: S11-S15 Ref: 6 ref.
1993
บทคัดย่อ
The strategy used and the main concepts involved in the production of genetically modified full-flavour, red-ripe tomatoes with reduced levels of the enzyme polygacturonase (PG) are briefly described. Tomato lines were transformed with a chimaeric gene in which a 730 bp fragment from the 5' end of the PG cDNA clone pTOM6, including the start of the protein coding region, was fused to a 528 bp fragment of the CaMV 35S promoter and a 261 bp nopaline synthase terminator sequence. Transgenic tomato lines exhibiting inhibited PG activity by more than 99% were selected and tests showed that the character was stably inherited. Fruit textural qualities such as firmness are altered in modified tomatoes due to an increase in the molecular weight of pectin. This alteration, however, does not compromise the nutritional quality and composition of the tomatoes. Tasting trials involving more than 100 people in both the UK and USA over the last 2 years have indicated that the modified tomato has desirable marke
t qualities. Chemical analysis, toxicological evaluation in rats fed with a 30% tomato diet and conclusions from an independent ethics committee have shown so far that the transgenic tomatoes do not impose any risk to humans. Further evaluations are underway to ensure safety and define in detail the nutritional characteristics of the improved tomatoes.