More than just an insect killer: The non-insecticidal activities of Bacillus thuringiensis with biotechnological potential

Abstract

Bacillus thuringiensis (Bt) is known for the biological control of important insect pests, but scientific advances have revealed several interesting characteristics, in addition to this classical function as a bioinsecticide. To investigate the current knowledge about these non-insecticidal activities, a systematic research on primary data in the scientific literature was conducted on alternative functions of Bt with biotechnological potential. Out of a total of 140 articles selected, 15 non-insecticidal Bt activities were found. Publications related to this topic are available since 1971, and different metadata were reported, such as biomolecules and genes involved in Bt performances in non-insecticidal bioactivities. A total of 11 Bt activities with different effect measures (response variables) were identified, with an average of 48 distinct Bt strains evaluated per activity. Approximately 81.2% of all identified experiments/tests deal with the direct effects of Bt on target cells/organisms, with 36.3% of the strains within these studies tested for antibacterial action; of all microbial targets tested, 92.8% are bacteria, which led to 75.2% of the experimental conditions for all direct activities being performed in vitro. Regarding indirect Bt activities, 67.6% of these studies reported tritrophic Bt-plant-pathogen interactions. Bioremediation also appears as a relevant Bt activity being investigated in-depth. Alternative Bt activities offer innovative ways of developing biotechnology for different areas of anthropic interest; hence, we also focus on the possibility of finding multifunctional strains of Bt, as this may be advantageous from a bioeconomic point of view. Our findings are discussed in terms of research trends, aspects, details and depth of the current knowledge on alternative non-insecticidal Bt traits. We also discuss the potential application of this science for useful technological developments, aiming at solving issues related to human health, sustainable agriculture and environmental preservation/restoration.