Bacillus thuringiensis-based biopesticides, are as effective as they should be?

LEOPOLDO PALMA*

REVISTA ARGENTINA DE MICROBIOLOGíA

ASOCIACION ARGENTINA MICROBIOLOGIA

Lugar: Buenos Aires; Año: 2017

0325-7541

Bacillus thuringiensis (Bt) synthesizes a number of invertebrate active toxins mainly active against insects and has demonstrated its potential and safety as a biocontrol agent for several years. The insecticidal proteins include both crystal (Cry and Cyt) and vegetative (secretable) insecticidal proteins (Vip) highly toxic against insects. To date, the Bt-based biopesticides represent a clear alternative to chemical insecticides and account for about 80% of all biopesticides marketed worldwide. Chemical insecticides contaminate water and food sources, are harmful for non-target organisms and generate insect resistance. The Bt-based biopesticides are very specific for their target insects and biodegradable. In fact, their biodegradability becomes their main disadvantage since the active ingredient, a mix of spores and crystals, is susceptible to natural abiotic factors: pH, temperature and UV light from sun. This disadvantage has stimulated the development of different encapsulation approaches intended to protect and extend the shelf life of sprayable Bt-based formulations. The encapsulation of Bt toxins into recombinant bacteria, is a convenient tool for enhancing their filed persistence and deserves further investigations since it will allow not only protecting the active ingredient but also to concentrate secretable insecticidal proteins (e.g Vip3) for the production of novel formulations.