Isolation and characterization of a new Bacillus thuringiensis strain Lip harboring a new cry1Aa gene highly toxic to Ephestia kuehniella (Lepidoptera: Pyralidae) larvae.
The aim of this study was to characterize new Bacillus thuringiensis strains that have a potent insecticidal activity against Ephestia kuehniella larvae. Strains harboring cry1A genes were tested for their toxicity, and the Lip strain showed a higher insecticidal activity compared to that of the reference strain HD1 (LC50 of Lip and HD1 were 33.27 and 128.61 μg toxin/g semolina, respectively). B. thuringiensis Lip harbors and expresses cry1Aa, cry1Ab, cry1Ac, cry1Ad and cry2A. DNA sequencing revealed several polymorphisms in Lip Cry1Aa and Cry1Ac compared to the corresponding proteins of HD1. The activation process using Ephestia kuehniella midgut juice showed that Lip Cry1A proteins were more stable in the presence of larval proteases. Moreover, LipCry1A proteins exhibited higher insecticidal activity against these larvae. These results indicate that Lip is an interesting strain that could be used as an alternative to the worldwide used strain HD1.
Institut Charles Gerhardt Montpellier, Equipe MACS, 8 rue de l'Ecole normale, Montpellier Cedex 5, France.
Micheline
M
El Khoury
Hichem
H
Azzouz
Alain
A
Chavanieu
Nouha
N
Abdelmalak
Joël
J
Chopineau
Mireille Kallassy
MK
Awad
D000818:Animals; D001413:Bacillus thuringiensis / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism / Q000502:physiology*; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism*; D004731:Endotoxins / Q000235:genetics* / Q000378:metabolism*; D006460:Hemolysin Proteins / Q000235:genetics* / Q000378:metabolism*; D007814:Larva / Q000382:microbiology; D007915:Lepidoptera / Q000382:microbiology*; D008969:Molecular Sequence Data; D010572:Pest Control, Biological
D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D004731:Endotoxins; D006460:Hemolysin Proteins; C030956:insecticidal crystal protein, Bacillus Thuringiensis