the expression of stress tolerance-related genes in
response to drought, high salinity and cold stress in
plants (Kumar and Rosen, 2006). The yield of DREB
transgenic soybean can be greatly increased due to
its tolerance to drought. Concerns have been raised
because the release of transgenic plants worldwide
would endanger ecologic system and their replacement
of traditional crops would reduce biodiversity.
The response of soil biodiversity to transgenic plant
has been investigated in many studies. Engineered
gene or its products may be released into soil via plant
litter, sloughed and root exudation. Horizontal gene