Recovery of transgenic Gladiolus cells. The plasmid, pAct1-
F4, which contains an Act1- GUS chimeric gene, was co-bombarded
with p35SAc DNA into nonregenerable Gladiolus cells.
For selection, bombarded cells were moved to MS basal salts
medium containing either PPT or bialaphos. After 4 weeks, healthy,
yellow microcalli began to appear against a background of dead
cells. The microcalli were subculture to PPT-containing medium
for continued growth. When PPT-resistant Gladiolus cells were
assayed for GUS activity (Fig. 2A), »70% of the transformants that
contained the PAT gene as determined by PCR analysis expressed
detectable levels of GUS enzyme. This co-expression rate compares
favorably with the rates observed in other plant transformation
systems after co-bombardment with two plasmids. Suspension
cells of ‘Jenny Lee’ expressed high levels of GUS (25 to 40
nmol MU/h per mg protein), which is comparable to the highest
levels reported for other monocots (Hagio et al., 1991; Lyznik et
al., 1989).