Chapter 22 – Biotechnological Approaches

The defense system of plants provides a resistance mechanism to protect them from insect attack. In spite of prevailing defense mechanisms of plants, insects cause severe losses in crop productivity. In view of growing food production demands, there is a need to manage insect damage in an environmentally friendly manner as an alternative to synthetic pesticides. An ecological way is the development of insect-resistant cultivars through molecular approaches coupled with well-defined mechanisms of action at transcriptome and genetic levels. A classic example of foreign gene introduction in plants is expression of Bacillus thuringiensis (Bt) endotoxin genes in plants to protect them against some insects. However, due to problems related to biosafety aspects of Bt plants, approaches have been made to exploit plants' own defense systems to develop insect resistant plants by manipulating the expression of their endogenous defense proteins or introducing an insect control gene derived from another plant. Host plant resistance is one of the most effective forms of insect control and offers a very good alternative to insecticides. The development of powerful molecular genetic tools allows genome-wide association studies to dissect the molecular diversity underlying variations in insect resistance. Such analyses facilitate the development of molecular markers and enhance marker-assisted breeding in order to identify resistance traits into economically important cultivated crops. This chapter deals with the biochemical features and mechanisms of actions of plant proteins supposedly involved in defense mechanisms against insects. The potentialities of genetic engineering of plants with increased resistance to insect predation relying on the repertoire of genes found in plants are also discussed.