Question

A tissue of a tobacco plant infected with TMV was used to obtain a new plant. Identify the techniques used & reason out the possibility of obtaining a new healthy plant.

Answer 1

Hint: Tobacco mosaic virus is a positive single strand RNA virus, where it infects the wide range if plants, especially tobacco, and virus got the name because infection causes characteristic patterns such as mosaic like mottling, and it causes the discoloration of leaves, it was the first virus that was discovered.

Complete answer:
There are some techniques one can use the virus-infected plants to produce new plants, one is heat treatment of the plant cells, so that virus in the cells get inactivated, and can divide and produce the new plant, but this may not possible as we don’t know that, where some plants cannot tolerate the high temperature.
Another method is chemical treatment, where the virus infected plants cells are cultivated, the culture media should be treated with certain chemicals like cytokines or other, so that chemicals inactivate or kills the virus and make them not to propagate along with plant cells, but this is different in different species of plants, so this is the reason where it may possible in all plants.
So in plants which is infected by the virus, instead of using virus affected cells, using the meristematic cells is the best option, as we know that this are rapid dividing cells which are present as apical and lateral meristematic cells, even though the plants are infected by virus, this cells are free of virus because they divide very faster than the replication of virus, so by using the plant tissue culture technique, Meristematic cells can be cultured to produce the virus free plants from the infected plants.

Note: To explain it in simple manner, tissue culture of meristematic cells of virus infected plants are used to produce the virus free healthy plants because meristematic cells are undifferentiated rapidly dividing cells, they divide very fast than the replication of virus, this is the reason, this cells can be used for tissue culture.