title: Toxicity, activation process, and histopathological effect of Bacillus thuringiensis vegetative insecticidal protein Vip3Aa16 on Tuta absoluta.
abstract: Tuta absoluta is a destructive moth of Solanaceae plants and especially tomatoes. Here, we considered the entomopathogenic activity of the Bacillus thuringiensis Vip3Aa16 protein heterologously produced by Escherichia coli against T. absoluta. Purified Vip3Aa16 showed lower lethal concentration 50 % against third instar larvae (Toxin/tomato leaf) (335 ± 17 ng/cm(2)) compared to that of B. thuringiensis kurstaki HD1 δ-endotoxins (955 ± 4 ng/cm(2)) (P < 0.05). Action mode examination showed that Vip3Aa16 (88 kDa) was more sensitive to proteolysis activation by the chymotrypsin than the trypsin or the larvae gut soluble proteases, yielding derivative proteins essentially of about 62 and 33 kDa. The gut-soluble proteases could contain trypsin-like enzymes implicated in Vip3Aa16 activation since the proteolysis was inhibited using specific protease inhibitors. Additionally, we showed that the histopathological effect of Vip3Aa16 on T. absoluta larva midguts consisted on a microvillus damage and an epithelial cell rupture.
authors.affiliation: Biopesticides Team (LPAP), Center of Biotechnology of Sfax, University of Sfax, P.O. Box 1177, 3018, Sfax, Tunisia.
authors.forename: Sameh
authors.initials: S
authors.lastname: Sellami
authors.forename: Maroua
authors.initials: M
authors.lastname: Cherif
authors.forename: Lobna
authors.initials: L
authors.lastname: Abdelkefi-Mesrati
authors.forename: Slim
authors.initials: S
authors.lastname: Tounsi
authors.forename: Kaïs
authors.initials: K
authors.lastname: Jamoussi
mesh_terms: D000818:Animals; D001413:Bacillus thuringiensis / Q000737:chemistry / Q000378:metabolism*; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism / Q000633:toxicity*; D002918:Chymotrypsin / Q000037:antagonists & inhibitors / Q000378:metabolism; D004731:Endotoxins / Q000235:genetics / Q000378:metabolism / Q000633:toxicity; D004789:Enzyme Activation; D004847:Epithelial Cells / Q000187:drug effects* / Q000648:ultrastructure; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D041981:Gastrointestinal Tract / Q000187:drug effects / Q000648:ultrastructure; D015870:Gene Expression; D006460:Hemolysin Proteins / Q000235:genetics / Q000378:metabolism / Q000633:toxicity; D007814:Larva / Q000187:drug effects* / Q000648:ultrastructure; D018551:Solanum lycopersicum / Q000469:parasitology; D008970:Molecular Weight; D009036:Moths / Q000187:drug effects* / Q000648:ultrastructure; D010572:Pest Control, Biological; D018515:Plant Leaves / Q000469:parasitology; D011480:Protease Inhibitors / Q000494:pharmacology; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism / Q000633:toxicity; D059748:Proteolysis; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism / Q000633:toxicity; D014357:Trypsin / Q000378:metabolism
chemical_list: D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D004731:Endotoxins; D006460:Hemolysin Proteins; D011480:Protease Inhibitors; D020033:Protein Isoforms; D011994:Recombinant Proteins; C447139:Vip3A protein, Bacillus thuringiensis; C030956:insecticidal crystal protein, Bacillus Thuringiensis; D002918:Chymotrypsin; D014357:Trypsin