Identifying proteins with insecticidal activity: use of encoding genes to produce insect-resistant transgenic crops

Abstract

Crops resistant to insect attack offer an alternative strategy of pest control to a total reliance upon chemical pesticides. Transgenic plant technology can be a useful tool in producing resistant crops, by introducing novel resistance genes into a plant species. This technology is seen very much as forming an integral component of a crop management programme. Several different classes of plant proteins have been shown to be insecticidal towards a range of economically important insect pests from different orders; in some cases a role in the defence of specific plant species against phytophagous insects has been demonstrated. Genes encoding insecticidal proteins have been isolated from various plant species and transferred to crops by genetic engineering. Amongst these genes are those that encode inhibitors of proteases (serine and cysteine) and α-amylase, lectins, and enzymes such as chitinases and lipoxygenases. Examples of genetically engineered crops expressing insecticidal plant proteins from different plant species, with enhanced resistance to one or more insect pests from the orders Lepidoptera, Homoptera and Coleoptera are presented. The possibility of ‘pyramiding’ different resistance genes to improve the effectiveness of protection and durability is discussed and exemplified. The number of different crop species expressing such genes is very diverse and ever-increasing. The viability of this approach to crop protection is considered. © 1998 SCI.