Which of the following statements is correct regarding Agrobacterium tumefaciens and T-DNA transfer?

All of the above statements are correct.

a-Tumour formation is induced by the Ti (tumour-inducing) plasmid.

b-The transfer of T-DNA into plant cells causes tumour formation.

c-Agrobacterium tumefaciens, a soil-inhabiting plant bacterium and a pathogen of several dicot plants, is capable of transferring a piece of DNA known as T-DNA.

d-All of the above statements are correct is the correct option .

Agrobacterium tumefaciens is a soil-inhabiting plant bacterium known for its ability to transfer a piece of DNA called T-DNA into the cells of certain dicot plants. This transfer of T-DNA is facilitated by a plasmid known as the Ti (tumour-inducing) plasmid, which is present in the bacterium.

When Agrobacterium infects a plant cell, the T-DNA is transferred and integrated into the plant cell's genome. The T-DNA carries genes responsible for causing tumour formation in the plant, leading to the development of abnormal growths or galls. These galls provide a unique environment that supports the growth and multiplication of Agrobacterium, allowing it to complete its lifecycle.

The process of T-DNA transfer and tumour formation has been widely studied and exploited in genetic engineering and biotechnology. Scientists have modified the T-DNA to remove tumour-causing genes and replace them with genes of interest, such as genes for desirable traits or novel proteins. By doing so, they can use Agrobacterium as a vector to deliver the desired genes into the plant cells and create genetically modified plants with specific characteristics.

Overall, Agrobacterium tumefaciens and its T-DNA transfer mechanism have become essential tools in plant biotechnology, allowing for the development of genetically modified crops with improved traits, such as resistance to pests, diseases, or environmental stresses.