COLD REQUIREMENT FOR MAXIMAL ACTIVITY OF THE BACTERIAL ICE NUCLEATIONPROTEIN INAZ IN TRANSGENIC PLANTS

The bacterial ice nucleation gene inaZ confers production of ice nucle i when transferred into transgenic plants. Conditioning of the transfo rmed plant tissue at temperatures near 0 degrees C greatly increased t he ice nucleation activity in plants, and maximum ice nucleation activ ity was achieved only after low-temperature conditioning for about 48 h. Although the transgenic plants contain similar amounts of inaZ mRNA at both normal and low temperatures, low temperatures are required fo r accumulation of INAZ protein. We propose that the stability of the I NAZ protein and thus ice nucleation activity in the transgenic plants is enhanced by low-temperature conditioning.