www.checkbiotech.org ; www.raupp.info ; www.czu.cz

The inheritance of the chloroplasts (the organelles responsible for
photosynthesis) in most plants is maternal, as these organelles are not
carried by the pollen grains (which produce the sperm cells). The
manipulation of the chloroplast genome for crop improvement is therefore
considered a very valuable tool for improving the containment of the
transgene, and enhancing in this way the biosafety of transgenic plants.
A team of researches led by Ralph Bock from the Max-Planck Institute for
Molecular Plant Physiology in Germany have recently evaluated the strictness
of maternal inheritance, by measuring the rates at which chloroplasts are
transmitted through the pollen. The team reports a low level of paternal
inheritance (only 39 seeds were identified with chloroplasts derived from
the father plant among over 2 million seeds examined).

The results indicate that plastid transformation is a good tool for
preventing gene flow. However, in cases where transmission of the transgene
through the pollen must be totally prevented, the team recommends adopting
additional containment strategies to eliminate the risk of outcrossing. The
research is published in the latest issue of PNAS.

[www.isaaa.org]