Novel strains of bacillus thuringiensis and pesticidal composition comprising them

Abstract

The present invention relates particularly to a strain of Bacillus thuringiensis characterized in that it expresses the gene sigma E (σE) and does not sporulate at all or little sporulates or does not produce any viable spores. The invention also relates to a pesticide composition containing said strain of Bacillus thuringiensis.

1 )  Bacillus thuringiensis  characterized in that it expresses the sigma E (θE) gene and does not sporulate or sporulates little or does not produce viable spores.  
     
     
         2 )  Bacillus thuringiensis  according to  claim 1 , characterized in that the strain does not sporulate.  
     
     
         3 )  Bacillus thuringiensis  according to one of claims  1  and  2 , characterized in that it is a strain not expressing the sigma K gene.  
     
     
         4 )  Bacillus thuringiensis  according to  claim 3 , characterized in that the SigK gene has been interrupted by introduction of a DNA sequence or has been at least partially deleted.  
     
     
         5 )  Bacillus thuringiensis  according to  claim 4 , characterized in that the sigK gene has been interrupted by introduction of a DNA sequence conferring a positive selection character on the strain.  
     
     
         6 )  Bacillus thuringiensis  according to  claim 5 , characterized in that the positive selection character is resistance to an antibiotic.  
     
     
         7 )  Bacillus thuringiensis  according to one of  claims 1  to  6 , characterized in that the Bt strain expresses one or more Cry genes.  
     
     
         8 )  Bacillus thuringiensis,  according to  claim 7 , characterized in that the Cry gene(s) is/are carried by a vector, for example a plasmid.  
     
     
         9 )  Bacillus thuringiensis  according to  claim 7 , characterized in that the Cry genes are integrated into the chromosome.  
     
     
         10 )  Bacillus thuringiensis  according to one of  claims 1  to  9 , characterized in that it expresses a protein of interest carried by a self-replicating plasmid or by a DNA sequence integrated into the chromosome.  
     
     
         11 )  Bacillus thuringiensis  according to  claim 10 , characterized in that it contains a DNA sequence in the SigK gene expressing a protein of interest.  
     
     
         12 )  Bacillus thuringiensis  according to  claim 10 , characterized in that it contains in replacement of all or part of the SigK gene a DNA sequence expressing a protein of interest.  
     
     
         13 )  Bacillus thuringiensis  407 SigK −  (pHT410) deposited at the National Collection of Microorganism Cultures of the Institut Pasteur on Oct. 26, 1995 under the number I-1634.  
     
     
         14 )  Bacillus thuringiensis  Kto SigK −  (pHTF3-1C/A(b)-IRS-T-Δ) deposited at the National Collection of Microorganism Cultures of the Institut Pasteur on Oct. 22, 1996 under the number I-1776.  
     
     
         15 ) Pesticidal composition, characterized in that it contains a Bt strain according to one of  claims 1  to  14 .  
     
     
         16 ) Composition according to  claim 15 , characterized in that the Bt strain has been inactivated.  
     
     
         17 ) Composition according to one of claims  15  and  16 , characterized in that it has been inactivated by physical means.  
     
     
         18 ) Composition according to one of claims  15  and  16 , characterized in that it has been inactivated by irradiation.  
     
     
         19 ) Composition according to one of claims  15  and  16 , characterized in that it has been inactivated by chemical means.  
     
     
         20 ) Composition according to one of  claims 15  to  19 , characterized in that the Bt strain has been treated to improve the digestibility of the strain or alternatively to improve the accessibility of the protein.  
     
     
         21 ) Composition according to  claim 20 , characterized in that the Bt strain has been treated by sonication.  
     
     
         22 ) Nucleotide sequence containing the SigE gene, not containing any active SigK gene and containing a sequence coding for a gene of interest.