Genetic manipulation in Bacillus thuringiensis for strain improvement

Abstract

Bacillus thuringiensis (Bt) has been used as a biopesticide in agriculture, forestry and mosquito control because of its advantages of specific toxicity against target insects, lack of polluting residues and safety to non-target organisms. The insecticidal properties of this bacterium are due to insecticidal proteins produced during sporulation. Despite these ecological benefits, the use of Bt biopesticides has lagged behind the synthetic chemicals. Genetic improvement of Bt natural strains, in particular Bt recombination, offers a promising means of improving efficacy and cost-effectiveness of Bt-based bioinsecticide products to develop new biotechnological applications.

Sustainable Horticultural Systems

“…Strain selection and improvement can be achieved via genetic tools to increase toxicity against target insects, broaden the host spectra, improve field persistence, and optimize fermentation production, as reviewed by Sansinenea et al (2010). Although there is little new information on the genetic manipulation, the desirability for discovering new strains and biopesticides to mitigate insecticide and Bt resistance cannot be underscored for the sustainable development of agriculture.…”

Can (We Make) Bacillus thuringiensis Crystallize More Than Its Toxins?

“…Using Bt to produce custom nanocrystals in vivo could therefore be envisioned by capitalizing on the knowledge acquired during the last decades on the mode of action of Bt toxins and their mechanisms of crystallization. A variety of tools allowing the genetic manipulation of Bt , notably including a large set of shuttle vectors ( Figure 1 B), have been developed to modify Bt strains and stably express a large variety of toxins and toxin complexes [ 14 , 47 ]. In addition, several acrystalliferous Bt strains, i.e., curated from their plasmids that carry toxin genes, have been developed for the recombinant production of toxin crystals [ 48 , 49 , 50 , 51 ].…”

Secondary metabolites of soil Bacillus spp.

“…These crystals are composed of proteins, known as insecticidal crystal proteins (ICPs), also called Cry proteins, which are selectively toxic to different species of several invertebrate phyla. Much of the technology developed to study structure and function of Cry proteins has provided the foundation for genetic engineering of this class of biopesticides (Sansinenea et al 2010). Formerly, only the insecticidal properties of B. thuringiensis attracted extensive attention.…”