A Transferrin Fragment Isolated from the Egyptian Cotton Leaf Worm, Spodoptera littoralis (Boisduval) (Lepidoptera: Noctuidae) in Response to Two Commercial Bioinsecticides.

Abstract

Bioinsecticides are needed to diminish environmental biohazards and host resistance to conventional insecticides against insect pests. Immune defense against biopesticides is a critical factor in their application. Transferrin is a protein involved in immune response, iron metabolism, and may act as antioxidant in insects. In this study, the insect immune response upon treating 4^th instar larvae of S. littoralis with bioinsecticides Viruset (SpliNPV only) and Profect (Bt+SpliNPV) was studied in terms of detecting and monitoring transferrin gene expression. Polymerase chain reaction (PCR) permitted the isolation of 215 bp fragments corresponding to putative S. littoralis transferrin gene (SpliTsf) from both control and treated insects. The deduced amino acid sequence showed high homology to other insect transferrins. The Gene expression of SpliTsfpost-immune challenge with bioinsecticides was determined using qRT-PCR. It was found that Profect caused upregulation in SpliTsf expression, while Viruset caused its down-regulation. The role of transferrin in immune response was discussed.