title: Activity of vegetative insecticidal proteins Vip3Aa58 and Vip3Aa59 of Bacillus thuringiensis against lepidopteran pests.
abstract: Vegetative insecticidal proteins (Vips) secreted by some isolates of Bacillus thuringiensis show activity against insects and are regarded as insecticides against pests. A number of B. thuringiensis strains harbouring vip3A genes were isolated from different sources and identified by using a PCR based approach. The isolates with the highest insecticidal activity were indicated in screening tests, and their vip genes were cloned and sequenced. The analysis revealed two polymorphic Vip protein forms, which were classified as Vip3Aa58 and Vip3Aa59. After expression of the vip genes, the proteins were isolated and characterized. The activity of both toxins was estimated against economically important lepidopteran pests of woodlands (Dendrolimus pini), orchards (Cydia pomonella) and field crops (Spodoptera exigua). Vip3Aa58 and Vip3Aa59 were highly toxic and their potency surpassed those of many Cry proteins used in commercial bioinsecticides. Vip3Aa59 revealed similar larvicidal activity as Vip3Aa58 against S. exigua and C. pomonella. Despite 98% similarity of amino acid sequences of both proteins, Vip3Aa59 was significantly more active against D. pini. Additionally the effect of proteolytic activation of Vip58Aa and Vip3Aa59 on toxicity of D. pini and S. exigua was studied. Both Vip3Aa proteins did not show any activity against Tenebrio molitor (Coleoptera) larvae. The results suggest that the Vip3Aa58 and Vip3Aa59 toxins might be useful for controlling populations of insect pests of crops and forests.
authors.affiliation: Department of Microbiology, Faculty of Biology, Adam Mickiewicz University, Poznań, Poland.
authors.forename: Jakub
authors.initials: J
authors.lastname: Baranek
authors.affiliation: Department of Microbiology, Faculty of Biology, Adam Mickiewicz University, Poznań, Poland. Electronic address: akazn@amu.edu.pl.
authors.forename: Adam
authors.initials: A
authors.lastname: Kaznowski
authors.affiliation: Department of Microbiology, Faculty of Biology, Adam Mickiewicz University, Poznań, Poland.
authors.forename: Edyta
authors.initials: E
authors.lastname: Konecka
authors.affiliation: Department of Plant Physiology and Molecular Biology, Plovdiv University, Plovdiv, Bulgaria.
authors.forename: Samir
authors.initials: S
authors.lastname: Naimov
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001413:Bacillus thuringiensis; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D007915:Lepidoptera / Q000469:parasitology*; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D010572:Pest Control, Biological / Q000379:methods*; D016133:Polymerase Chain Reaction
chemical_list: D001426:Bacterial Proteins; C447139:Vip3A protein, Bacillus thuringiensis
keywords: Bacillus thuringiensis; Insecticidal activity; Lepidoptera; Vegetative insecticidal proteins