Taken together, the conspicuous overrepresentation of drugresistance associated proteins, including the ABCC proteins together with the members of the subfamily B and G, in the excretion system suggests a role for these candidates in the extrusion of xenobiotics or phytochemicals from the larval body. The fat body of insects is a polymorphic tissue. It performs a vast array of fundamental activities in the intermediary metabolism and is involved in maintaining the homeostasis of hemolymph proteins, lipids, 20(S)-Protopanaxatriol and carbohydrates. Predominantly, the storage of lipid reserves in the form of glycogen and triglycerides is essential in the life of holometabolous insects, primarily in their survival of metamorphosis. In humans, members of the subfamilies A, B, D and G are known to be involved in lipid transport. In principal, we found the expression of ABC transporters in the larval fat body of C. populi to be low compared to the other tested tissues. From the ABCB subfamily, we identified in the fat body only Cpabc8 exhibiting a low transcript level comparable to that of the Malpighian tubules. As described above, it clusters with the human mitochondrial ABCB10 which is associated with different functions,SB242084 also described above, but not particularly with lipid transfer. From ABCG we found Cpabc51 and Cpabc55 with high expression in the fat body. Both deduced proteins cluster to the human ABCG1 and ABCG4. Only one sequence was exclusively expressed in this body part, namely Cpabc41, a member of the subfamily C. Other ABCC members which are highly expressed in this tissue are the homologous Cpabc16 and Cpabc35. CpABC35 is known to translocate phytochemicals. Noticeably, we found high expression of putative ABCH genes in the fat body tissue. Up to now the function of this insect specific subfamily has been unclear. However, RNAi targeting Tcabch-9c in the flour beetle revealed a lethal, desiccated phenotype similar to the silencing of Tcabcg-4c mentioned above. This ABCH member also seems to be involved directly or indirectly in the transport of lipids from epidermal cells to the cuticle. Based on our data we can hypothesize a role for ABC transporters in phytochemical translocation, in cuticle formation in the fat body, but not particularly in the lipid storage of this tissue.