Herbicides are chemicals that kill plants. Some plants are genetically modified to resist herbicide applications. Herbicides are developed to be effective against numerous weeds, but will not kill GM crops. Weeds need to be controlled because they could have a huge impact on crop yield. By introducing a new gene into a herbicide-sensitive plant, it is possible to increase the plant's tolerance to the herbicide (Ahmad et al. 2012). De Freitas et al. introduced an anti-apoptotic baculovirus p35 gene into the passion fruit genome (De Freitas et al. 2012). Expression of the p35 gene reduced the progression of programmed cell death caused by the herbicide glufosinate. The enzyme glutamine synthase inhibits glufosinate, leading to the buildup of ammonia, which stimulates the production of a chemical toxic to plants. The transgenic passion fruit plant showed increased tolerance towards the herbicide glufosinate when the non-transgenic plant was compared with the transgenic plant (De Freitas et al. 2012). Fruits infected with disease-causing microorganisms can be a big problem for humanity, because the less fruit is available, the more pesticides and fungicides will be used, which will put more pressure on the environment. Pesticides and fungicides can be expensive (Uzogara 2000). Green mold caused by Penicillium digitatum, a post-harvest disease, is a major problem for citrus fruits, leading to post-harvest losses. A study was conducted to control green mold by applying the Paenibacillus polymyxa SG-6 strain to citrus fruits. After application, the bacteria inhibited the growth of Penicillium digitatum, and Lai and colleagues found that green mold growth was reduced more quickly if the center of the paper benefited. Journal of Chromatography B 756(1-2): 327-335.• Streatfield, S.J. 2007. Approaches to achieve high-level heterologous protein production in plants. Plant Biotechnology Journal 5: 2-15.• Trivedi, PK and Nath, P. 2004. MaExp1, an ethylene-induced expansin from banana fruit ripening. Plant Science 167: 1351-1358.• Uzogara, SG 2000. The impact of genetic modification of human foods in the 21st century: a review. Biotechnology Advances 18 (3): 179-206.• Varoquaux, F., Robert, B., Michel, D., and Patrick, G. 2000. Less is more: new approaches for seedless fruit production. Trends in Biotechnology 18 (6): 233-242.• Wasserman, S.A. 2008. Animal nutrition. In Campbell, N.A., Reece, J.B., Urry, L.A., Cain, M.L., Wasserman, S.A., Minorsky, P.V. and Jackson, R.B. (Eds.), Biology, Rearson Benjamin Cummings. 1267 pages. (ISBN: 9780321536167).