The technology that underlies DNA Plant Technology Corp.'s(DNAP) next generation of tomatoes is now subject to a patentallowance notification that applies to all plants, not just thepetunias in which "transwitch" gene suppression was firstdeveloped.

The technology underlies the Cinnaminson, N.J., company's nextgeneration of Vinesweet tomatoes.

Versions launched this spring have been produced throughsomaclonal variation. Coming up next are tomatoes of the samestrain in which "transwitch" technology was used to preventoverripening, allowing development of full flavor andnutritional potential on the vine, as well as extended shelf life.

In transwitch technology, a duplicate of a naturally occurringgene is inserted into the chromosome, where, paradoxically, thetwo genes often appear to cancel each other out as their geneticinformation is processed, leading to elimination of the traitwhose expression they govern.

DNAP (NASDAQ:DNAP) received U.S. Patent No. 5,034,323 in1991 for use of this technology to change the color of petunias.DNAP considers transwitch a genetic engineering breakthroughfor improving quality and yield performance in crops, and "theonly practical alternative" to gene suppression using antisensetechnology. Antisense technology is currently encumbered bypatent disputes.

"Undisputed patent protection of our transwitch technology willallow DNAP to maintain its leadership position in plant geneticengineering," said Robert Serenbetz, DNAP's president and chiefexecutive officer. "Several companies are now embroiled inpatent disputes concerning antisense, leaving no clear path foruse of this method by any third party."

The core of DNAP's plant genetic engineering program,transwitch is expected to be an additional source of revenuesthrough third-party licensing agreements.

"Gene suppression in plants will likely be required for a leasthalf of all plant genetic engineering during the next decade,"said John Bedbrook, executive vice president of DNAP. He wasinstrumental in developing transwitch in early experiments onchanging flower color. "In our development studies, transwitchgene suppression has shown three to five times higherefficiency over antisense technology. This is an important costadvantage in carrying our genetic engineering."

The Vinesweet tomato is leading the company's effort topenetrate the $4 billion retail fresh tomato market, as well asother branded produce markets. Transwitch technology is alsobeing used to improve sweetness and texture in such productsas peppers, cherry tomatoes and sugar snap peas that DNAP isdeveloping for FreshWorld, the company's joint venture withDu Pont.

-- Nancy Garcia Associate Editor

(c) 1997 American Health Consultants. All rights reserved.