Transgenic plants in dicotyledons have been produced for crop improvement, to become herbicide, insect and viral resistant.

Herbicides normally affect processes like photosynthesis or biosynthesis of amino acids. One can develop resistant plants either by making target molecules insensitive to herbicide or by overproducing the target protein. Another approach is introduction of a pathway that will detoxify the herbicide. All these methods have been tried. To induce insect resistance the toxin gene (bt2) from bacteria B. thuringiensis was isolated. The Bt toxins produced by this bacteria has been used as a biological insecticide since long time. The bt2 gene was used for Agrobacterium Ti plasmid mediated transformation of tobacco, cotton, and tomato plants. The transgenic plants were resistant to the Manducta sexa which is a pest of tobacco.

Induction of resistance to storage pests was clearly demonstrated in cowpea, Vigna unguiculata. In this plant a trypsin inhibitor (CpTI) is responsible for its resistance to attack by the major storage pests and insects. The gene CpTI was transferred to induce insect resistance by using binary vectors. The vector was mobilized into Agrobacterium, which was used to infect tobacco leaf discs. This lead to the production of transgenic tobacco plants expressing high level of CpTi thereby making the plant resistant against a variety of insects.