The minimal promoter that we used was the -60 promoter from the 35S gene of cauliflower mosaic virus. This minimal promoter contains a TATA box but by itself is not capable of directing high levels of transcription. The -60CaMV-GUS-3'NOS construct was made by isolating a 2.2 kb EcoRI/HindIII fragment from pBIN421.9 (Clontech), filling in with Klenow, and cloning into pGEM7z/SmaI to create plasmid pD979. A 2.2 kb BamHI/Asp718 fragment was isolated from pD979 and cloned into the unique BamHI and Asp718 sites of the binary plant transformation vector pCGN1547 to create plasmid pD991.