Agrobacterium Tumefaciens and T-DNA Transfer

Agrobacterium tumefaciens is a bacterium that naturally engineers plant genetics by transferring a part of its DNA, known as the TI plasmid, into plant cells. This process involves the activation of vir genes and proteins, leading to the integration of T-DNA into the plant genome. The T-DNA expresses genes that cause plant cells to produce hormones and opines, benefiting the bacterium. Researchers exploit this mechanism to genetically modify plants by replacing T-DNA with desired genes, allowing for genomic integration without tumor formation.

What is the primary role of the TI plasmid in Agrobacterium tumefaciens?

• To protect the bacterium from predators

• To transfer DNA into a plant cell

• To enable the bacterium to move

• To produce food molecules for the plant

How does Agrobacterium tumefaciens recognize a wounded plant?

• By detecting light signals

• By sensing temperature changes

• By feeling physical contact

• By recognizing phenolic compounds

What is the function of the vir genes in Agrobacterium?

• To protect the bacterium from viruses

• To activate the transfer of T-DNA

• To create opines

• To produce plant hormones

What happens to the T-DNA once it is inside the plant cell nucleus?

• It integrates into the plant genome

• It is destroyed by the plant

• It remains inactive

• It exits the plant cell

What is the result of the expression of T-DNA genes in plant cells?

• Production of more flowers

• Increased plant height

• Formation of a crown gall tumor

• Enhanced root growth

What is the role of the protein VirD2 in the T-DNA transfer process?

• It protects the T-DNA from degradation

• It cleaves the T-DNA

• It directs the T-DNA into the plant cell

• It integrates the T-DNA into the plant genome

Which plant hormones are synthesized due to T-DNA expression?

• Abscisic acid and jasmonic acid

• Cytokinin and auxin

• Salicylic acid and brassinosteroids

• Gibberellins and ethylene

What are opines, and why are they important for Agrobacterium?

• They are plant hormones that help in growth

• They are sugars that provide energy to the plant

• They are amino acid derivatives used as a nutrient source

• They are proteins that protect the plant

How do researchers use Agrobacterium in genetic engineering?

• By using it to increase plant resistance to pests

• By employing it to transfer genes of interest into plants

• By employing it to enhance plant photosynthesis

• By using it to produce more opines

What is the advantage of using Agrobacterium without tumor-inducing genes?

• It allows for faster plant growth

• It enables the integration of recombinant genes without causing tumors

• It increases the production of opines

• It enhances the plant's immune system