Gene flow from transgenic soybean, developed to obtain recombinant proteins for use in the skin care industry, to non-transgenic soybean

Soybean has been recognized as a useful platform for heterologous protein production. This study compared the pollen characteristics of transgenic and non-transgenic soybean and investigated the rate of gene flow from transgenic soybean events, developed to obtain recombinant proteins (such as human epidermal growth factor, insulin-like growth factor 1, or thioredoxin) for use in the skin care industry, to non-transgenic soybean under field conditions, and determined the distance at which gene flow could occur. The lack of significant differences in pollen grain size, viability and pollen germination rates between transgenic and non-transgenic cultivars indicates that the overexpression of transgenes did not alter pollen characteristics in soybean. The highest rates of gene flow from the three transgenic soybean events to non-transgenic soybean ranged from 0.22 to 0.46% at the closest distance (0.5 m). Gene flow was observed up to 13.1 m from the transgenic plots. Our data fell within the ranges reported in the literature and indicate that an isolation distance greater than at least 13 m from transgenic soybean is required to prevent within-crop gene flow in soybean. As the potential markets for transgenic crops as a recombinant protein factory increase, gene flow from transgenic to non-transgenic conventional crops will become a key decision factor for policy makers during the approval process of transgenic crops. Our study may provide useful baseline data for the prevention of transgenic soybean seed contamination caused by transgene flow.