Biotech Updates

Biological Characterization of Two Bt Strains Toxic against Fall Armyworm

March 11, 2011

Bacillus thuringiensis (Bt) is a common bacterium found in soil known for its insecticidal properties due its ability to produce crystal proteins during production of spores. Once these Cry proteins are ingested by insects,  the cells in the midgut are broken down. Analia Alvarez of the Universidad Nacional de Tucuman, Argentina, together with other scientists isolated two Bt strains from dead fall armyworm (Spodoptera frugiperda) larvae for molecular and phenotypic characterization and also to determine its insecticidal activity against the destructive fall armyworm.

Results showed that both strains tested were highly toxic to armyworms in early stage of development  particularly during the first instar stage. One strain called Bacillus thuringiensis LSM, was found to be more toxic than the reference strain Bacillus thuringiensis var. kurstaki (Btk) 4D1. Molecular tests showed that Bt LSM and Btk have similar crygene profiles. Phenotypic characterization tests showed the differences in extracellular esterase profiles and lytic activity among the isolates. Results of the study could be used in biological control programs using Bacillus thuringiensis.

Read the abstract of this study at http://www.springerlink.com/content/72514257435355l2/.