Question

Source organism of cry genes is -

• A. Bacillus thuringiensis
• B. Agrobacterium tumefacien
• C. Rhizobium
• D. Staphylococcus

Hint:

Remember the link: {cry} genes produce insecticidal {cry}stals. They come from {B}acillus {t}huringiensis, the source of the famous {Bt} toxin.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
The question asks for the origin of the 'cry genes', which are important in creating insect-resistant transgenic crops.
Step 2: Detailed Explanation:
The cry genes encode for Cry proteins, which are crystalline protein toxins produced by the soil bacterium {Bacillus thuringiensis}. These proteins are specifically toxic to certain insect larvae (like caterpillars, beetles, and fly larvae).
The abbreviation Bt used in crops like Bt-cotton and Bt-brinjal stands for Bacillus thuringiensis. The cry genes from this bacterium are isolated and transferred into plants to make them produce the insecticidal protein, thus protecting them from specific pests.
Agrobacterium tumefaciens is used as a vector to transfer genes but is not the source of cry genes.
Rhizobium is a nitrogen-fixing bacterium.
Staphylococcus is a genus of bacteria often associated with human infections.
Step 3: Final Answer:
The source organism of cry genes is Bacillus thuringiensis.