Bacillus thuringiensis (Bt) strains have been used for designing novel

Bacillus thuringiensis (Bt) is a Gram-positive bacterium that produces crystals during sporulation. These crystals comprise ~130 kDa protoxins called as crystal proteins which are potent and highly specific insecticides. Once ingested by specific host, these crystals dissolve in the alkaline conditions of the gut thereby activating the protoxins. The active toxins then bind to receptors on midgut epithelial cells, become inserted into the plasma membrane where they form pores leading to cell death through osmotic lysis. This special feature of Bt toxin was explored in genetic engineering to produce bioinsecticidal plants. Biofertilizers are the microorganisms which increase the nutrient availability from soil to plants thereby causing nutrient enrichment, for example free living and symbiotic nitrogen fixing bacteria and Cyanobacteria. Process by which living organisms produce minerals is called as biomineralization that lead to the hardening or stiffening of the mineralized materials; example includes formation of silicates in algae and diatoms. Biometallurgy is the study of the economic potential of the interactions between the microbes and the minerals and is used for exploitation of mineral resources and in environmental protection.

So, the correct answer is 'Bioinsecticidal plants'