Insect-resistant plants

Insect resistant plants, 12 486 Insect-resist treatment, of wool,... 

Phytoecdysones, due to their effects on the behavior and the development of certain species of Insects, appear to be components of multichemical defensive strategies found In some Insect-resistant plant species ... 

Breeders have selected celery with relatively high amounts of psoralens because farmers prefer to grow insect resistant plants and consumers prefer to buy undamaged produce. Unfortunately, workers who harvest such celery sometimes develop a severe skin rash (NAS 2004), an unintended consequence of this conventional breeding. It is possible that if the gene encoding the toxic protein had been cloned and studied before being introduced into the new varieties, farm workers would have learned of the harmful effects before exposure. 

Natural Products as Inducers of Insect Resistance. Plant growth regulators have been shown to increase the biosynthesis of certain secondary plant constituents that in turn decrease plant attack by insects. -Naphthaleneacetic acid, for example, elicits increased terpene biosynthesis in citrus, thus decreasing attack by fruit flies. The approach of using both natural and synthetic plant growth regulators may continue to find applications in insect control. 

Pittendrigh, B., P. Gaffney, J. Huesing, L. Onstad, and L. Murdock. 2004. Active refuges can inhibit the evolution of resistance in insects towards transgenic insect-resistant plants. J. Theor. Biol. 231 461-474. 

In addition, naturally growing plants resist plant pathogen and Insect attack because resistance develops over time via natural selection (35). Also, most natural and crop plants have, as a part of their basic physical and chemical makeup, a wide array of mechanisms that help them resist pest attack. These Include chemical toxicants, repellents, altered plant nutrients, hairiness, thorns, and diverse combinations of these (35). 

Scott, J.G., Liu, N.A., and Wen, Z. (1998). Insect cytochromes P450 diversity, insect resistance and tolerance to plant toxins. In D.R. Livingstone and J.J. Stegeman (Eds.) Forms and Function of Cytochrome P450, 147-156. 

DOWN R E, FORD L, BEDFORD S J, GATEHOUSE L N, NEWELL C, GATHOUSE J A, GATEHOUSE A M (2001) Influence of plant development and environment on transgene expression in potato and consequences for insect resistance. Transgenic Res. 10(3) 223-260. 

The development of resistant strains of an insect to a given insecticide is not new. Melander (7) in 1914 pointed out that the San Jose scale in Washington had developed a resistance to lime-sulfur sprays. Recently Babers (1) of the Bureau of Entomology and Plant Quarantine brought together an excellent evaluation and summary of the literature dealing with the development of insect resistance to insecticides he lists 111 references to work on this phenomenon. 

Bell, H. A., Down, R.E., Fitches, E.C., Edwards, J.P. and Gatehouse, A.M.R. (2003). Impact of genetically modified potato expressing plant derived insect resistance genes on the predatory bug, Podisus maculiventris (Heteroptera Pentatomidae). Biocontrol Science and Technology 13 729-741. 

The levels of antifeedants can be raised safely only in plants such as forest trees or fiber crops, not in food plants for humans or livestock. Such problems have arisen inadvertently. For instance, a new insect-resistant potato cultivarhad to be withdrawn from the market because it contained high levels of the carcinogens solanine and chaconine (Renwick etal, 1984). In another example, an insect-resistant celery had 10 times the usual concentration of the carcinogen 8-methoxypsoralen (and related psoralens), which caused dermatitis in produce handlers (Seligman etal, 1987). 

Interactions Among Allelochemicals and Insect Resistance in Crop Plants... 

Hedin, P.A. and Waage, S.K., Roles of flavonoids in plant resistance to insects, in Plant Flavonoids in Biology and Medicine Biochemical, Pharmacological and Structure Activity Relationship, Cody, V., Middleton, E., and Harbome, J.B., Eds., Alan Liss, New York, 1986, 87. 

Function and Chemistry of Plant Trichomes and Glands in Insect Resistance... 

---