Transgenic plants have genes inserted into them that are derived from another species. The inserted genes can come from species within the same kingdom (plant to plant) or between kingdoms (for example, bacteria to plant). In many cases the inserted DNA has to be modified slightly in order to correctly and efficiently express in the host organism. Transgenic plants are used to express proteins like the cry toxins from B. thuringiensis, herbicide resistant genes, antibodies[37] and antigens for vaccinations[38]
Transgenic carrots have been used to produce the drug Taliglucerase alfa which is used to treat Gaucher's disease.[39] In the laboratory, transgenic plants have been modified to increase photosynthesis (currently about 2% at most plants to the theoretic potential of 9–10%.[40] This is possible by changing the rubisco enzyme (i.e. changing C3 plants into C4 plants[41]), by placing the rubisco in a carboxysome, by adding CO2 pumps in the cell wall,[42][43] by changing the leaf form/size.[44][45][46][47] Plants have been engineered to exhibit bioluminescence that may become a sustainable alternative to electric lighting.[48] Still other transgenic plants have been modified to fix ambient nitrogen.[49]