GENETIC-ENGINEERING OF DISEASE AND PEST RESISTANCE IN PLANTS - PRESENT STATE-OF-THE-ART

Rapid progress in gene technology has allowed, on the one hand, insigh t to be gained into the complex molecular mechanisms of plant/pathogen recognition and the natural defence strategies of host plants. On the other hand, this technology can also be used for the controlled and e fficient generation of genetic variability and for the identification of desirable genotypes, far beyond the possibilities of classical bree ding. The first successful attempts have been made to improve resistan ce against pathogenic viruses, bacteria, fungi and insects by engineer ing transgenic plants. The majority of these strategies were based on constitutively expressing single proteins that are either toxic to the pathogen/pest, or interfere with its reproductive cycle. More refined strategies, which are at the stage of testing, try to mimic and modif y naturally-evolved defence reactions of plants and, thereby, will pot entially confer a more durable resistance to a broad range of pathogen s.