Question

Which of the following represents the correct sequence of steps in leaf disc transfer method?

• A. Dedifferentiation $\to$ cutting leaf discs $\to$ redifferentiation $\to$ agrobacterium infection
• B. Cutting leaf discs $\to$ dedifferentiation $\to$ agrobacterium infection $\to$ redifferentiation
• C. Agrobacterium infection $\to$ redifferentiation $\to$ cutting leaf discs $\to$ dedifferentiation
• D. Cutting plant discs $\to$ agrobacterium infection $\to$ dedifferentiation $\to$ redifferentiation

Answer 1

The correct option is B Cutting leaf discs $\to$ dedifferentiation $\to$ agrobacterium infection $\to$ redifferentiation

In leaf disc method for transformation, small discs are cut from leaf. This induces stress. Stressed leaf disc cells undergo dedifferentiation. Dedifferentiation makes the cells totipotent and with appropriate hormones they can grow into any other plant tissue. At this step, cells are infected with agrobacterium containing tamed Ti plasmid with the gene of interest. The desired gene gets integrated with plant genome. Cells are then allowed to redifferentiate into roots and shoots forming the transgenic plant.