Despite numerous efforts that have been done for evaluation of toxicity kind of plant lectins against insect, their mechanism of action is not clearly understood. Therefore , the aim of this project was to identify putative target receptor protein(s) in the midgut of larvae of the cotton leafworm Spodoptera littoralis that are responsible for binding of Galanthus nivalis L. (snowdrop) agglutinin (GNA) . After dissection and 800 larvae midguts the water soluble and memebrane protein were fractioned and chromatographed on a column with immobilized GNA. SDS-PAGE analysis of the proteins eluted from the GNA column revealed many different GNA-binding proteins among which 4 soluble protein with polpeptides, of approxmate ly 26, 42, 50 and 72 kDa tand 6 membrane proteins composed of 26, 34, 42, 50 74 and 78 kDa, subunites. N-terminal sequencing identified the 26 kDa soluble protein band (TQXHVNPVDIQDXVTG ) as secreted ferritin and 50 kDa band (YKNPYYAANRSVNVHLF) as α –amylase. 32 and 26 kDa polypeptides from the membrane protein fraction (ADTAYQDVSGDXXAXT and TQXHVNPVTIXXEXXM) revaled sequence homology to ferritin from the midgut of hornworm, Manduca sexta and silkworm Bombyx mori respectively. in conclusion , we hope that with this new information we can sustaine the use an exploitation of insecticidal lectins to enhance the resistance of crops against pest insects into an IPM strategy..
