Gene Cloning in Plant Cells and Why are Plants Cloned?

Keywords

Vegetative propagating, asexual reproduction, reproduction, fungi, bacteria.

Introduction

Plant cloning is a technique for vegetatively propagating plants in which a piece of the stem or root of the source plant is placed in a suitable medium such as moist soil, potting mix, coir, or rock wool. The cutting produces new roots, stems, or both, and thus becomes a new plant independent of the parent.

Asexual reproduction is a naturally occurring phenomenon in many species, including most plants and some insects. Plants are survivors that have lived on earth long before the first animals. Plants can make clones of themselves naturally, using many different methods, such as layering, stolon, or tubers. Making clones is an advantage for plants under stable unchanging environmental conditions.

One reason plants have been able to adapt to every environment on the planet is their unique methods of reproduction. Most plants, on the other hand, can produce offspring asexually from only a single parent through cloning. Since the parent plant was successful in that environment, it is also likely that the clones will survive to reproduce. Clones start life as a multi-celled part of the parent plant and can grow to colonize areas quickly.

Cloning a plant artificially is done using different methods depending on the species. Some methods of cloning utilize offspring volunteers that the plant produces naturally and can be separated from the parent.

Such cloning is usually faster and has a higher success rate since the parent plant often provides the offspring with water and nutrients as it develops. Other types of cloning methods involve separating a fragment, or part, from the parent plant, and growing it under ideal conditions of temperature, light, and humidity.

Some common methods of cloning plants involve cutting, grafting, layering, and tissue culture. It is a reproduction method used by plants, fungi, and bacteria, and is also the way that clonal colonies reproduce themselves. Examples of these organisms include blueberry plants, Hazel trees, the Pando trees, the Kentucky coffee tree, Myrica, and the American sweetgum.

Why are Plants Cloned?

Creating plants by cloning is a benefit because it assures that the offspring plants will have the same features, and traits, as their parent plant. The benefit of cloning is that it consistently produces plants with the same desirable traits as the parent.

Plants have been "cloned" from stem cuttings or whole-plant divisions for many centuries, perhaps dating back as far as the beginnings of agriculture. When a cutting from a plant is taken and grown into a new plant (vegetative propagation), you are cloning the original plant because the new plant has the same genetic makeup as the donor plant.

Vegetative propagation works because the end of the cutting forms a mass of non-specialized cells called a callus. As an example, grapes, potato, and banana. Stem cuttings, root cuttings, scion cuttings, eye cuttings, leaf cuttings are some of the common methods.

Tissue culture and cloning are important in growing identical plants produced by genetic engineering. In this method propagation is done by taking pieces of specialized roots, breaking them up into root cells and growing the cells in a nutrient-rich culture. In culture, the specialized cells become unspecialized (dedifferentiated) into calluses.

The calluses can then be stimulated with the appropriate plant hormones to grow into new plants that are identical to the original plant from which the root pieces were taken. This procedure has been widely used by horticulturists to grow prized orchids and other rare flowers. It also happens to be the most difficult and requires a decent amount of experience to get it right.

Grafting and budding are horticultural techniques used to join parts from two or more plants so that they appear to grow as a single plant. In grafting, the upper part (scion) of one plant grows on the root system (rootstock) of another plant. In the budding process, a bud is taken from one plant and grown on another.

Another thing to think about when deciding what to clone is whether the plant is a dicot or a monocot. A dicot is a plant that develops different branches (herb, chard, vine plant, etc.) while a monocot has one single stalk (asparagus, corn, onions, etc.). For cloning, dicots would be more successful since there are branches that you can cut and clone while keeping the original plant intact. Herb clones traditionally perform well-some varieties to try including thyme, sage, basil, and mint.

Advantages of Plant Cloning

A few advantages include:

• All the plants have the same genotype and hence phenotype.
• The plants produced are free of disease.
• The plants can be genetically modified to confer immunity to certain diseases.
• Genetic modification enables growers to ensure that plants carry very distinct characteristics.
• The process is rapid and can yield large numbers of new plants.
• The small plants that are produced can be transported easily to other sites.
• Plants that are difficult to grow from their seeds can be produced by plant cloning.
• Plants can be grown in any country, in any season.
• Rare and endangered species can be propagated to save them from extinction.
• Whole plants can be created from genetically modified cells/tissues.
• The use of cultivars prevents the risk of F1 hybrids that occur when plants are crossed and grown from seeds, so the products are more uniform.

Disadvantages of Plant Cloning

Some of the disadvantages are as follows:

• It is an expensive and labor-intensive process.
• The process is susceptible to microbial contamination.
• There is no genetic variation, so all the offspring are susceptible to the same diseases or other environmental factors.
• This risks large-scale loss of a country's/continent's crop of a particular plant, so a range of cultivars is recommended.
• New plants must be carefully screened for abnormalities that could lead to the new plants being infected.
• There is a risk of an unexpected secondary metabolic chemical reaction that could cause stunted growth or even death in the new explants.

Conclusion

Plants are cloned to produce identical plants quickly and economically. Producing new plants by cloning is quicker than allowing plants to reproduce than collecting and sowing seeds. It's therefore an effective way of producing new individuals from rare and endangered plants, helping to preserve the species. Clones will also be genetically identical to the original plant providing the meristem cells. This is useful to provide crop plants for large-scale cultivation that have desirable characteristics such as disease resistance.