diseases continue to pose a serious public health threat worldwide.
Scientists and doctors are involved in an intensive effort to understand
the molecular features of host-pathogen relationships and are always
on the look-out for ideal model systems to study. A group of researchers
at the CNRS Centre de Génétique Moléculaire
(CGM)* have identified an insect pathogen which may offer important
insights for human disease.
CGM group studies infections in the fruitfly Drosophila. Drosophila
offers several attractive features, such as a relatively simple immune
system and powerful experimental genetics. In response to microbial
infections, Drosophila produce a battery of potent anti-bacterial
and anti-fungal peptides. However, no natural bacterial pathogen of
Drosophila had been identified previously that induces these
peptides. After an extensive search the researchers identified a bacterial
strain, Erwinia carotovora, which was capable of infecting
Drosophila larvae and activating anti-bacterial peptide genes1.
Erwinia carotovora is a phytopathogenic bacteria which causes
blackleg disease in potatoes and uses flies as a vector to propagate
between plants. The Erwinia-Drosophila infection is highly
specific and the bacteria appear to have evolved to exploit the fly
host. Furthermore, Drosophila may benefit from the fruit rot
produced by the phytopathogenic bacteria. Hence, this complex co-evolution
of flies and bugs offers an attractive system for subsequent identification
of the genes regulating key features of host-pathogen interactions.
Centre de Génétique Moléculaire, F-91198 Gif-sur-Yvette,
Basset A., Khush R. S., Braun A., Gardan L., Boccard F., Hoffmann
J. A., Lemaitre B. The phytopathogenic bacteria Erwinia carotovora
infects Drosophila and activates an immune response. Proc.
Natl. Acad. Sci. USA (2000) 97: 3376-3381.