Studies on adaptations of Metarhizium anisopliae to life in the soil

Metarhizium anisopliae is an important fungal model for elucidating the basis of entomopathogenicity. A field trial conducted in 2000 with a strain expressing the gfp gene as a marker unexpectedly identified the rhizosphere (the root–soil interface) as the site where insects and pathogen most likely interact. However, the implications of rhizosphere events in maintaining large populations of M. anisopliae remain unclear. The extent to which plant ecology is impacted by the rhizosphere competence of M. anisopliae is also uncertain, but it could be considerable with implicit co-evolutionary implications. Rhizosphere competence may need to be considered as a feature for selecting fungal strains for biocontrol and this raises the possibility of managing the rhizosphere microflora to achieve insect control. Rhizosphere competence also raises some concerns, particularly if it resulted in introduced or hypervirulent transgenic strains persisting in the environment. It is hoped that field trials and other studies currently underway to extend our knowledge of host–pathogen–plant interactions will help identify containment strategies as well as lead to new and important ways of exploiting insect pathogenic fungi for crop protection.