Understanding the impact of Bacillus thuringiensis proteins on non-target organisms

Abstract

Bacillus thuringiensis (Bt) is a spore-forming, gram-positive, aerobic, rod-shaped bacterium. During sporulation, Bt produces proteinaceous crystals called Cry proteins that are lethal to many insects' species, so are commonly used as biological pesticide. Transgenic Bt crops are genetically altered to express insecticidal toxins that cause fatality of a number of general agricultural pests. The insecticidal toxins formed by Bt crops possess narrow range of toxicity and therefore less non-target impacts as compared to conventional insecticides. A decrease in the amount and regularity of insecticide applications are financially advantageous. In numerous regions of the world, insecticide inputs have been significantly reduced because of Bt. The use of Bt crop technology might help in worldwide food security by escalating the amount and steadiness of crop yields. Though impact of Bt toxin on non-targeted organism is a serious issue yet no conclusion could still be drawn from several studies. This review summarizes the benefits of Bt crops including the impact on non-targeted organisms and Bt toxins having potential risks with respect to the environment.

Decrease in faeces removal and soil bioturbation by dung beetles in genetically modified maize plantations in southern Brazil

“…Toxins produced by Bacillus thuringiensis (Berliner) strains have characteristics that allow the selection of specific targets: Cry I is specific for lepidopterans (Koziel et al, 1993), whereas Cry III targets coleopterans (Herrnstadt et al, 1986). However, their effect on non‐target organisms (NTO) is controversial, showing non‐lethal harmful effects on non‐targets, e.g., changes in development, survival, and behaviour (Delm et al, 1999; Ramirez‐Romero et al, 2008; Lövei et al, 2009; Holderbaum et al, 2015; Alves & Hernández, 2017), or no effects (Naranjo, 2014; Yaqoob et al, 2016; Shu et al, 2019; Singh et al, 2019; Yin et al, 2020).…”