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Characterization of a Bacillus thuringiensis strain with a broad spectrum of activity against lepidopteran insects
Author(s) -
Martínez Clara,
Porcar Manuel,
López Alejandro,
De Escudero Iñigo Ruiz,
PérezLlarena Francisco J.,
Caballero Primitivo
Publication year - 2004
Publication title -
entomologia experimentalis et applicata
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.765
H-Index - 83
eISSN - 1570-7458
pISSN - 0013-8703
DOI - 10.1111/j.0013-8703.2004.00156.x
Subject(s) - bacillus thuringiensis , biology , helicoverpa armigera , spodoptera littoralis , aedes aegypti , lepidoptera genitalia , culex pipiens , exigua , anopheles stephensi , strain (injury) , botany , biological pest control , spodoptera , microbiology and biotechnology , noctuidae , larva , bacteria , recombinant dna , gene , biochemistry , anatomy , genetics
The insect pathogen Bacillus thuringiensis is suitable for use in biological control, and certain strains have been developed as commercial bioinsecticides. The molecular and biological characterization of a Bacillus thuringiensis subsp. aizawai strain, named HU4‐2, revealed its potential as a bioinsecticide. The strain was found to contain eight different cry genes: cry1Ab, cry1Ad, cry1C, cry1D, cry1F, cry2, cry9Ea1 , and a novel cry1I ‐type gene. Purified parasporal crystals from strain HU4‐2 comprised three major proteins of 130–145 kDa, which were tested for their insecticidal potency to four species of Lepidoptera ( Helicoverpa armigera , Spodoptera exigua, S. littoralis, and S. frugiperda ) and three species of mosquito ( Culex pipiens pipiens, Aedes aegypti , and Anopheles stephensi ). The crystal proteins were highly toxic against all the species of Lepidoptera tested, moderately toxic against two of the mosquito species ( C. pipiens and Ae. aegypti ), but no toxicity was observed against a third species of mosquito ( An. stephensi ) at the concentrations used in our study. The LC 50 values of the HU4‐2 Bt strain against H. armigera larvae (5.11 µg/ml) was similar to that of HD‐1 Bt strain (2.35 µg/ml), the active ingredient of the commercial product Dipel®. Additionally, the LC 50 values of the HU4‐2 Bt strain against S. littoralis , S. frugiperda , and S. exigua (2.64, 2.22, and 3.38 µg/ml, respectively) were also similar to that of the Bt strain isolated from the commercial product Xentari® for the same three species of Spodoptera (1.94, 1.34, and 2.19 µg/ml, respectively). Since Xentari® is significantly more toxic to Spodoptera spp. than Dipel® and, reciprocally, Dipel® is significantly more toxic against H. armigera than Xentari®, we discuss the potential of the HU4‐2 strain to control all these important lepidopteran pests.