Search Results
Transgenic `Rutgers' 37-81^ tomato (Lycopersicon esculentum Mill.) homozygous for a pectin methylesterase (PME) antisense gene, which lowers PME activity and increases levels of soluble solids, was compared to azygous (a segregating line of 37-81^ with 0 copies of the introduced gene) and wild-type `Rutgers' in the field during Summer 1992 and 1993 to determine the effects of the introduced PME antisense gene on tomato plant growth, fruit set, fruit yield, and fruit processing attributes. Fresh and dry weight accumulation in transgenic plants was similar to wild-type `Rutgers' and azygous 37-81^ lines during 1992 and 1993, indicating that the introduced PME antisense gene did not affect biomass accumulation. Transgenic plants showed an increase in fruit number and yield in 1992 compared to wild-type `Rutgers' and azygous 37-81^, but no differences were observed among the three genotypes in 1993. Average fruit weight did not show significant differences among the three genotypes in 1992, but was lower in azygous and transgenic plants than wild-type plants in 1993. Transgenic fruit had higher soluble and total solids and higher pH than control fruit, but shelf life was somewhat shorter in transgenic fruit. Overall, these data indicate that introduction of the PME antisense gene, which improves the processing quality of tomatoes, does not adversely affect fruit yield or vegetative growth of plants.
We have introduced an antisense pectin methylesterase (PME) gene into Rutgers tomato to elucidate its role in fruit development and ripening. In greenhouse trials tomato fruits from transformant 37-81^ homozygous for the antisense PME gene ripened normally and contained higher levels of soluble solids than wild-type Rutgers fruits (Tieman et al. (1992) Plant Cell 4:667-679). Field trials of transgenic 37-81^ homozygous and azygous for the antisense PME gene and wild-type Rutgers were conducted during the summer of 1992. Field grown fruits from homozygous 37-81^ plants have significantly higher levels of soluble solids and total solids and a higher fruit pH than Rutgers or 37-81^ azygous fruits. Average fruit weight did not differ significantly in the three genotypes, but 37-81^ (homozygous) plants had a higher total fruit yield than Rutgers or 37-81^ azygous plants. Plant fresh and dry weights did not differ significantly among the three plant types.