Leps, Bt, and corn pollen

[Jim Steffens]

The issue with respect to effects on non-target species is the presence of
Bt protein in corn pollen.  When foreign genes are put into plants, they
require 'promoters,' pieces of DNA which tell the nucleus to turn the DNA
into RNA, which is then made into protein.
Promoters come in various strengths, meaning that they cause expression to
occur at different levels.  Promoters can also be tissue-specific, meaning
that, if desired, Bt could be targeted to roots (to control corn rootworm)
or green tissue (to control European corn borer).  The promoter used in
this case was clearly a non-specific promoter, and probably one from the
cauliflower mosaic virus (CMV), which is often used to achieve high levels
of expression in plant tranformation.  Even then, whoever did the work had
to select from among the transformants a plant expressing high levels of
Bt.

If it can be demonstrated that Bt in corn pollen has a major impact on
non-target species, then Monsanto should be able to target Bt to green
tissue alone.  This is more difficult, but it can be done.  Corn borers
love pollen, but probably the most important damage is to the ear and the
whorl.