Question

Which of the following controls/control the growth of bollworms?

• A. CryIAc and CryIIAb genes
• B. CryIAb gene
• C. RNAi
• D. dsRNA

Answer 1

The Correct Option is A

In the context of controlling bollworm pests, genetically engineered plants incorporate specific genes to produce toxins that target these pests. The CryIAc and CryIIAb genes are part of the Cry (crystal) protein family originating from Bacillus thuringiensis (Bt), a bacterium known for naturally producing insecticidal proteins. 

These Cry genes are introduced into crop plants, enabling them to produce these proteins in their tissues, which are toxic to specific insects like bollworms but generally harmless to humans and other non-target organisms. When bollworms consume parts of the Bt plant, the Cry proteins bind to receptors in the gut of the insects, which leads to cell lysis and eventually the death of the insect, thus effectively controlling their population.

Other options such as RNAi (RNA interference) and dsRNA (double-stranded RNA) represent different gene-silencing technologies and mechanisms and are not directly used for controlling bollworms in this context. Therefore, the use of the CryIAc and CryIIAb genes in genetically modified crops is the correct answer for controlling the growth of bollworms.

Answer 2

The CryIAc and CryIIAb genes are part of the Bacillus thuringiensis (Bt) technology, which is used to control the growth of bollworms and other pests. These genes produce Cry proteins that are toxic to certain insects, including the bollworm, when they ingest the protein. These proteins disrupt the gut cells of the pest, leading to its death.

• CryIAc and CryIIAb genes are commonly inserted into genetically modified crops like Bt cotton, providing them with resistance to bollworm attacks.
• CryIAb gene (Option 2): This gene alone may also provide protection, but in many cases, a combination of Cry proteins (such as CryIAc and CryIIAb) offers broader and more effective pest control.
• RNAi (Option 3) and dsRNA (Option 4) are technologies used in pest management but do not directly relate to the Bt genes. RNA interference (RNAi) and double-stranded RNA (dsRNA) are methods to silence specific genes in pests, potentially controlling pest populations, but Bt toxins like Cry proteins are more commonly used for bollworm control.

Thus, CryIAc and CryIIAb genes effectively control the growth of bollworms.