
For Real: A Store-Bought Tomato with
Vine-Ripened TasteBy Doris Stanley
Lowe May 12, 1999Changing the levels of a key hormone in
tomatoes could lead to fruit that tastes better and lasts longer,
Agricultural Research Service scientists
report. Research shows such a tomato to be only a few years away. ARS plant physiologist Jerry D. Cohen and colleagues have genetically
altered the levels of auxin, a hormone which causes a tomato to grow and ripen.
Its the best knownand probably the most importantof the five
major plant hormones. Scientists have been studying auxin for more than 120 years. Theyve
been able to change auxin levels, but the changes were expressed throughout the
plant, not just in the fruit. The aim is to control the hormone production so
that it can be introduced into specific, targeted tissues--such as the fruit--
without affecting the growth processes in other parts of the plant. At the ARS Horticultural Crops
Quality Laboratory in Beltsville, Md., Cohen and colleagues inserted a
backwards copy of iaglua gene from corninto a tomato to turn
this gene off. Because the gene was put in with a fruit-specific promoter, only
the tomato fruit was affected. The resultant fruit ripened more slowly. This
work is in collaboration with scientists in the ARS
Climate Stress Laboratory in
Beltsville. ARS is the chief scientific agency in the
U.S. Department of Agriculture. Another plus for auxin: Decreasing the genes level of expression
throughout receptor plants caused them to easily form large numbers of roots
from cuttings and spurred rapid root growth in germinating seedlings. This
could be significant for plants that are difficult to root from cuttings and
could increase the survival rate of seeds planted in dry soils. Cohen expects this research to produce a store-bought tomato with
vine-ripened taste in about 3 years. Scientific contact: Jerry D. Cohen, ARS Horticultural Crops Quality
Laboratory, Beltsville, Md., phone (703) 306-1442, fax (703) 306-0355,
[email protected] (on detail to the
National Science Foundation until October
1999). U.S. Department of Agriculture | |