Question

Arrange the following steps of somatic hybridisation in a correct sequence.
A. Digestion of cell walls.
B. Isolation of naked protoplasts.
C. Fusion of protoplasts to get hybrid protoplast.
D. Isolation of single cells from two different varieties of plants.
E. Growing of hybrid protoplast to form a new plant. Choose the correct answer from the options given below:

• A. E, A, B, C, D
• B. D, B, A, E, C
• C. E, B, A, D, C
• D. D, A, B, C, E

Hint:

Think of it as: \textbf{Get cells} $\rightarrow$ \textbf{Take off their coats} (walls) $\rightarrow$ \textbf{Merge them} $\rightarrow$ \textbf{Grow the hybrid}.

Answer 1

The Correct Option is D

Step 1 : Understanding the Question: The question asks for the logical and biological chronological order of steps involved in the process of somatic hybridization. This technique is a cornerstone of plant biotechnology, allowing for the fusion of vegetative (somatic) cells from two different plant varieties to create a hybrid with combined traits, bypassing the need for traditional sexual reproduction. Step 2 : Key Formulas and Approach: The fundamental approach in somatic hybridization is the "Protoplast Fusion" method. Because plant cells are encased in a rigid cellulose-based cell wall, the primary challenge is removing this barrier to facilitate the contact and fusion of the internal cellular components. The sequence follows a linear path: Cell Selection $\rightarrow$ Wall Removal $\rightarrow$ Protoplast Cleaning $\rightarrow$ Induced Fusion $\rightarrow$ Tissue Regeneration. Step 3 : Detailed Explanation:
Isolation of Source Material (D): The process initiates by selecting two distinct plant varieties that possess desirable characteristics. Individual cells are isolated from specific tissues (often the leaf mesophyll) of these plants to serve as the starting point for hybridization.
Cell Wall Digestion (A): Once single cells are obtained, their protective cell walls must be removed. This is achieved through enzymatic treatment using cellulase and pectinase. These enzymes dissolve the cellulose and pectin, effectively "shelling" the cell.
Protoplast Isolation (B): After the digestion of the cell wall, the remaining living unit of the cell, bounded only by the plasma membrane, is known as a "naked protoplast." These protoplasts are carefully isolated from the enzymatic mixture and cellular debris.
Protoplast Fusion (C): The isolated protoplasts from the two different plant sources are placed together in a medium. They are induced to fuse using chemicals like Polyethylene Glycol (PEG) or through electro-fusion, creating a single hybrid protoplast containing genetic material from both parents.
Regeneration of the Hybrid (E): The hybrid protoplast is then cultured in a specialized nutrient-rich medium. Under appropriate conditions, it regenerates a new cell wall and begins to divide, eventually differentiating into a full-grown hybrid plant.