Beneficial bacteria, Bacillus thuringiensis: Mini review on mechanisms, applications, and future prospects

Bacillus thuringiensis (Bt), a gram-positive bacterium, has long been a keystone of biological pest control for more than a century. Bt is renowned for producing crystal (Cry), cytolytic (Cyt), and vegetative insecticidal proteins (Vip), which together form a powerful defense against a broad spectrum of insect pests while minimizing effects on non-target organisms. Cry proteins produced during sporulation act as crystal δ-endotoxins that bind to receptors in the insect midgut, creating pores that disrupt epithelial integrity and lead to cell death. Cyt proteins function by directly interacting with lipid bilayers, leading to rapid cytolysis. Vip proteins, secreted during vegetative growth, enhance Bt’s effectiveness, particularly against pests that resist Cry toxins. The effectiveness of Bt has led to the development of Bt-transgenic crops in the 1980s and 1990s, reducing dependence on chemical pesticides and increasing crop yields. Through its role in integrated pest management, Bt fosters sustainable agriculture as an environmentally responsible alternative to traditional chemical pesticides. Despite its success, the evolution of pest resistance presents a major challenge, requiring the implementation of strategies such as gene stacking, RNA interference, and CRISPR-based technologies. The review covers Bt’s taxonomy, genetic diversity, ecological contributions, and future outlook, with a particular focus on its potential to address climate change and improve pest management practices and maintain the sustainability of Bt-based methods in agriculture and beyond.