. Three vectors, schematically depicted
in Figure 2, were constructed. pB19hpc combines the
sequences for a plant phytoene synthase (psy) originating from
daffodil (Narcissus pseudonarcissus; accession no. X78814) (4)
with the sequence coding for a bacterial phytoene desaturase
(crtI) originating from Erwinia uredovora (accession no.
D90087), the two being placed under the control of the
endosperm-specific glutelin (Gt1) and the constitutive CaMV
35S promoter, respectively. The phytoene synthase cDNA
contained a 5-sequence coding for a functional transit peptide,
as was demonstrated previously (5), while the crtI gene
was fused to the transit peptide sequence of the pea Rubisco
small subunit (tp), as constructed by Misawa et al. (6). This
plasmid, thus, should direct the formation of lycopene in the
endosperm plastids, the site of GGPP formation