Transgenic plants can express a wide variety of foreign genes and offe
r the opportunity of large-scale protein production in agricultural sy
stems. The recombinant protein can serve both ex situ and in situ purp
oses. Due to significant progress in plant molecular biology, many dif
ferent plant species can now be transformed and are even capable of pr
oducing very complex proteins such as antibodies or vaccines. Furtherm
ore, recombinant proteins can mediate resistance against microbial pat
hogens, such as fungi or viruses, or protect transgenic plants from in
sect pests.