A novel Fatty Acid Binding Protein produced by teratocytes of the aphid parasitoid Aphidius ervi.

Aphidius ervi is an endophagous braconid, parasitoid of the pea aphid, Acyrthosiphon pisum. A. ervi terato- cytes, deriving from the dissociation of the embryonic serosa, synthesize and release two major proteins into the host haemocoel. The gene of one of these proteins has been cloned and characterized. This gene codes for a 15.8 kDa protein belonging to the fatty acid binding protein (FABP) family, named Ae-FABP (A. ervi-FABP). It is abundantly present in the host haemolymph when the parasitoid larva attains its maximum growth rate. The recombinant Ae-FABP binds to fatty acids in vitro, showing a high affinity to C14–C18 saturated fatty acids and to oleic and arachidonic acid. The possible nutritional role for the parasitoid larva of Ae-FABP is discussed