Multiplicity of §‐endotoxin genes with different insecticidal specificities in Bacillus thuringiensis aizawai 7.29

Abstract

The hypothesis according to which multiple and different delta-endotoxin genes could determine the host-range specificity of the lepidopteran strains of Bacillus thuringiensis is being checked in the case of strains aizawai 7.29 (serotype 7) and entomocidus 601 (serotype 6). From these strains, several crystal protein genes, belonging to different structural types, have been isolated. One of the cloned genes that is not present in strain entomocidus 601 is duplicated in strain aizawai 7.29. This gene belongs to a previously characterized type of crystal protein gene and encodes a protein preferentially active against Pieris brassicae. Two other genes, of presumed chromosomal location, are present in both strains and each displays a unique physical map. In both strains the two genes are in close proximity and in the same orientation. The first, which belongs to a new type of crystal protein gene, encodes a 130-140 kD protein that is not significantly active against the two insect species tested. The other new type of crystal protein gene directs the synthesis of a polypeptide preferentially active against Spodoptera littoralis.

Diversity of <i>Bacillus thuringiensis</i> strains isolated from coffee plantations infested with the coffee berry borer <i>Hypothenemus hampei</i>

“…Several reports show a high frequency of certain cry1 gene combinations, for example the linkage cry1C-cry1D (Bravo et al 1998, Ferrandis et al 1999. The cry1C-cry1D linkage may be explained by their common location on the same replicon (Sanchis et al 1988). However, in this study cry1D gene was found alone at a relatively high frequency (24 strains) and only 7 strains presented such linkage.…”

Effects of Cry1Ab protoxin, deltamethrin and imidacloprid on the foraging activity and the learning performances of the honeybee Apis mellifera, a comparative approach

“…The Cry1Ab protoxin was 131 kDa in size (Gohar, personal communication), and was obtained from a gene cloned from the aizawai 7.29 strain in the pHTA1 plasmid (Sanchis et al, 1988).…”

Chronic Exposure of the European Corn Borer (Lepidoptera: Crambidae) to Cry1Ab <I>Bacillus thuringiensis</I> Toxin

“…This strain was a derivative of the wild-type B. thuringiensis strain 407 isolated by Lereclus et al (1989) which displayed the cry1Ab gene described by Sanchis et al (1988) without producing any spores. Consequently any differences in susceptibility among strains could be attributed to the Cry1Ab toxin.…”