Plant tissue specific gene expression by way of repressor-operator
complexes, has enabled outcomes including, without limitation, male
sterility and engineered plants having root-specific gene expression of
relevant proteins to clean environmental pollutants from soil and water.
A mercury hyperaccumulation strategy requires that mercuric ion reductase
coding sequence is strongly expressed. The actin promoter vector, A2pot,
engineered to contain bacterial lac operator sequences, directed strong
expression in all plant vegetative organs and tissues. In contrast, the
expression from the A2pot construct was restricted primarily to root
tissues when a modified bacterial repressor (LacIn) was coexpressed from
the light-regulated rubisco small subunit promoter in above-ground
tissues. Also provided are analogous repressor operator complexes for
selective expression in other plant tissues, for example, to produce male
sterile plants.