Question

With reference to the above diagram answer the questions that follow.
1 - Name the enzymes
2 - Identify the cells
3 - Name the cell
4 - Identify the particular step in somatic hybridisation
5 - Identify the cell

• A. 1 - Cellulase/pectinase, 2 - Protoplasts, 3 - Heterokaryon, 4 - Cell wall regeneration, 5 - Callus
• B. 1 - Chitinase/pectinase, 2 - Protoplasts, 3 - Heterokaryon, 4 - Cell wall regeneration, 5 - Callus
• C. 1 - Cellulase/protease, 2 - Chloroplasts, 3 - Heterokaryon, 4 - Cell wall regeneration, 5 - Callus
• D. 1 - Cellulase/chitinase, 2 - Heterokaryon, 3 - Protoplast, 4 - Callus, 5 - Cell wall regeneration

Answer 1

The correct option is A 1 - Cellulase/pectinase, 2 - Protoplasts, 3 - Heterokaryon, 4 - Cell wall regeneration, 5 - Callus

In somatic hybridisation, protoplasts of two different plant species fuse together to form somatic hybrids. For the production of somatic hybrids, first the protoplast is isolated from plant cells. For this, the following steps are followed:
1. Plant cells consist of a cell wall which has to be degraded if the protoplasts have to be obtained as required. For this purpose, the plant cell is treated with enzymes like pectinase, cellulase, etc. which cause hydrolysis of plant cell wall and enables isolation of protoplasts.
2. Different protoplasts isolated are treated with different mechanisms so that they fuse together. This can be done using electric pulses or by chemical treatment with a fusogen like polyethylene glycol. The resulting fused nucleus is called a heterokaryon.
3. The somatic hybrid cell or heterokaryon is then induced to produce a cell wall by using appropriate plant growth hormones.
4. Soon after the formation of wall around the protoplasts, the reconstituted cells show considerable increase in size. After 2-3 weeks, callus starts to form. The callus may be induced to undergo organogenic differentiation or whole plant regeneration.