Bacillus thuringiensis
Bacillus thuringiensis (often abbreviated to Bt) is a species of bacterium used for its insecticidal properties. It is a Gram-positive bacillus, facultatively aerobic, ubiquitous and spore-forming.
It is found in small quantities in virtually all soils, water, air and plant foliage. It is part of a group of six bacilli known as the " Bacillus cereus group " : B. anthracis (responsible for anthrax), B. cereus, B. mycoides, B. pseudomycoides, B. weihenstephanensis and B. thuringiensis.
Bacillus thuringiensis was isolated in 1901 by the Japanese bacteriologist S. Ishiwata from silkworms, which it can infect and kill, but its first scientific description was given by the German Ernst Berliner in 1911.
The acronym Bt is also frequently used to designate the pesticide molecule (insecticide, acaricide, etc.), sometimes called thuringiensin, obtained from this bacterium (or related bacteria such as Bacillus sphaericus), or produced by genetic engineering using plants (GMOs) into which certain fragments of the bacterium's genome have been introduced.
In 2006, Bt was the most widely used biopesticide (as a bioinsecticide), accounting for over 90 % of the bioinsecticide market, but just 2 % of the overall insecticide market (Fargues and Bourguet 2005). It is also produced by transgenic plants, with no effect on certaininsect species that have become resistant to it, or more or less so in some cases.()
