Plastid transketolase (TK) is another enzyme in the C3 cycle
that has been shown to have a significant effect on photosynthesis
and growth in antisense tobacco plants (Henkes et al., 2001).
Analysis of tobacco plants expressing an antisense construct for
plastid TK demonstrated that a small reduction in the activity of this
enzyme by 20 to 40% inhibited photosynthesis and significantly
decreased the levels of aromatic amino acids and phenylpropanoids
(Henkes et al., 2001).