Insect-resistant cotton plants have been genetically engineered by inserting a gene from a/an

Transgenic insect‑resistant cotton (Bt cotton) was created by inserting a bacterial toxin gene—the Cry family (for example Cry1Ac)—into cotton so the plant produces an insecticidal protein. In India, Bt cotton hybrids carrying the Cry1Ac gene were approved for commercial cultivation from the 2002 crop season following trials and adoption across several states [1]. The Cry toxin genes are isolated from the soil bacterium Bacillus thuringiensis (Bt) and then incorporated into plant genomes; plants expressing these Bt Cry proteins kill susceptible caterpillar pests when ingested [2]. Therefore the insect‑resistance gene source is a bacterium, not a virus, insect, or plant.

Sources

1. [1] Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 12: Major Crops and Cropping Patterns in India > Bt. Cotton in India > p. 40
2. [2] https://www.entsoc.org/sites/default/files/files/Science-Policy/2018/ESA-Factsheet-Bt.pdf