Question

Given below are a few statements regarding somatic hybridization. Choose the correct statements.
(i) protoplasts of different cells of the same plant are fused
(ii) protoplasts from cells of different species can be fused
(iii) treatment of cells with cellulase and pectinase is mandatory
(iv) the hybrid protoplast contains characters of only one parental protoplast.

• A. (i) and (iii)
• B. (i) and (ii)
• C. (ii) and (iii)
• D. (i) and (iv)

Answer 1

The correct option is C (ii) and (iii)

Somatic hybridisation:

Somatic hybridisation is a process of developing hybrid plants by the fusion of protoplasts of two plant cells belonging to different species which generates a hybrid protoplast with desired characteristics. This plant cell can be developed into a hybrid plant by tissue culture method.

Steps in somatic hybridisation :

• Isolation of desired protoplasts
• Fusion of desired protoplasts
• Protoplast culture
• Regeneration of the plantlets

Isolation of desired protoplasts.:

Isolation of desired protoplasts is done by digesting the cell wall with the digestive enzymes like pectinase,cellulase and hemicellulase. Thus this step is mandatory.

Fusion of desired protoplast:
Fusion of desired protoplast is done

• Either chemically with the help of a mixture of polyethylene glycol (PEG) and high concentration of calcium at pH 8.
• Or physically by electrofusion

The hybrid protoplast will have a combination of characteristics of both the parent protoplasts.

Protoplast culture and regeneration of the plant:

Once the wall appears around the fused protoplast or hybrid protoplast, it is cultured on a nutrient medium under controlled conditions to generate a plantlet which is a tiny plant having a root and a shoot. All the plantlets obtained from these tissue culture techniques are then transferred to the fields.

Correct statements:
Somatic hybridisation is a process of genetic modification in plants by the fusion of protoplasts of two plants belonging to different species which generates a hybrid plant with desired characteristics.
Desired protoplasts are isolated by the cell wall digesting enzymes like pectinase,cellulase and hemicellulase. Fusion of desired protoplast is done either physically or chemically.