TY - JOUR T1 - Variant vicilins from a resistant Vigna unguiculata lineage (IT81D-1053) accumulate inside Callosobruchus maculatus larval midgut epithelium. AU - Oliveira,Gabriel B, AU - Kunz,Daniele, AU - Peres,Tanara V, AU - Leal,Rodrigo B, AU - Uchôa,Adriana F, AU - Samuels,Richard I, AU - Macedo,Maria Lígia R, AU - Carlini,Célia R, AU - Ribeiro,Alberto F, AU - Grangeiro,Thalles B, AU - Terra,Walter R, AU - Xavier-Filho,José, AU - Silva,Carlos P, Y1 - 2013/11/09/ PY - 2013/09/11/received PY - 2013/11/02/revised PY - 2013/11/05/accepted PY - 2013/11/14/entrez PY - 2013/11/14/pubmed PY - 2014/9/11/medline KW - Antibiosis KW - Endocytosis KW - Insect midgut KW - Protein absorption KW - Vicilin SP - 45 EP - 52 JF - Comparative biochemistry and physiology. Part B, Biochemistry & molecular biology JO - Comp Biochem Physiol B Biochem Mol Biol VL - 168 N2 - It has been demonstrated that variant vicilins are the main resistance factor of cowpea seeds (Vigna unguiculata) against attack by the cowpea beetle Callosobruchus maculatus. There is evidence that the toxic properties of these storage proteins may be related to their interaction with glycoproteins and other microvillar membrane constituents along the digestive tract of the larvae. New findings have shown that following interaction with the microvilli, the vicilins are absorbed across the intestinal epithelium and thus reach the internal environment of the larvae. In the present paper we studied the insecticidal activity of the variant vicilins purified from a resistant cowpea variety (IT81D-1053). Bioassays showed that the seeds of this genotype affected larval growth, causing developmental retardation and 100% mortality. By feeding C. maculatus larvae on susceptible and IT81D-1053 derived vicilins (FITC labelled or unlabelled), followed by fluorescence and immunogold cytolocalization, we were able to demonstrate that both susceptible and variant forms are internalized in the midgut cells and migrate inside vesicular structures from the apex to the basal portion of the enterocytes. However, when larvae were fed with the labelled vicilins for 24h and then returned to a control diet, the concentration of the variant form remained relatively high, suggesting that variant vicilins are not removed from the cells at the same rate as the non-variant vicilins. We suggest that the toxic effects of variant vicilins on midgut cells involve the binding of these proteins to the cell surface followed by internalization and interference with the normal physiology of the enterocytes, thereby affecting larval development in vivo. SN - 1879-1107 UR - https://www.unboundmedicine.com/medline/citation/24220155/Variant_vicilins_from_a_resistant_Vigna_unguiculata_lineage__IT81D_1053__accumulate_inside_Callosobruchus_maculatus_larval_midgut_epithelium_ DB - PRIME DP - Unbound Medicine ER -