Genetics for improving biological control agents: the case of entomopathogenic nematodes

Genetics is a powerful means of enhancing the beneficial traits of biologic al control agents. This is exemplified by the enhancement of tolerance of t he entomopathogenic nematode (EPN) Heterorhabditis bacteriophora towards en vironmental extremes. The genetic approaches taken include selection (for h eat tolerance and resistance to nematicides); screening for natural isolate s displaying heat tolerance; hybridization (aided by genetic markers) and m utagenesis for generating mutants displaying either desired beneficial trai ts or marker mutations. Genetic engineering is a most promising tool for en hancing beneficial traits in biological control agents. The success in gene tic transformation of EPN opens the way for generating transgenic nematodes carrying genes conferring resistance to various environmental extremes. (C ) 2000 Elsevier Science Ltd. All rights reserved.