DNA Plant Technology Corp. will likely have to deal with a patent that issued to Monsanto Co. last week, if it is to commercialize its genetically engineered extended shelf-life tomato.

The U.S. patent, No. 5,352,605, covers CaMV promoters, the workhorse promoters used to control gene expression in genetically engineered plants. The 35-S promoters covered by the patent are derived from the cauliflower mosaic virus.