Biofortification and Plant Tissue Culture: Have you heard of Golden rice? An improved variety of rice containing beta-carotene, the yellow pigment that gives the rice its colour. It was developed as a supplement to treat vitamin A insufficiency.  This process of enriching the nutrient quantity of an edible is referred to as biofortification.

Biofortification and plant tissue culture have become important tools of present-day science. Plant tissue culture involves growing an entire plant using just a small part of the plant, like a small leaf, etc. Read along to learn about the fascinating details of biofortification plant tissue culture.

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Biofortification: Overview

Breeding crops to boost their nutritional worth is known as biofortification. This can be accomplished using either traditional selective breeding or genetic engineering. Biofortification varies from traditional fortification in that it focuses on improving the nutritional value of plant foods while they are still growing rather than adding nutrients to the meals after they have been processed. The objective of biofortification is to improve the following:

1. Essential vitamin content
2. Protein and lipid content and quality
3. Minerals and micronutrients content

Methods of Biofortification

Biofortification of essential micronutrients into crop plants can be achieved through three main approaches, namely transgenic, conventional, and agronomic, involving biotechnology, crop breeding, and fertilisation strategies, respectively.

Fig: Methods of Biofortification

Selective Breeding

Plant breeders use this strategy to look for existing types of crops that are naturally high in nutrients in seed or germplasm banks. They then crossed these high-nutrient types with high-yielding crop kinds to create a seed with both high yield and nutritional value. To have a quantifiable beneficial influence on human health, crops must be bred with appropriate levels of nutrients. As a result, nutritionists must be involved in their development, as they must determine if consumers of the upgraded crop can absorb the additional nutrients and the amount to which storage, processing, and cooking impact the accessible nutritional levels of the crops. Cows that generate a lot of milk, for example. Plants that generate a lot of grain, such as wheat.

Genetic Modification

Genetic modification is a process for altering a plant’s, animal’s, or microorganism’s properties by transferring a fragment of DNA from one organism to another. This is accomplished by selectively removing desirable genes from one organism’s DNA and transferring them to the other. Golden rice is a GM crop that was created for its nutritional benefits.

Seed Priming

Seed priming is a process of regulating the germination process by managing the temperature and seed moisture content, and the seed is taken through the first biochemical processes within the initial stages of germination. Seed treatments for agronomic biofortification are a convenient way to harvest higher yields of micronutrient-rich cereals.

Seed priming with micronutrients improved stand establishment, yield-contributing characteristics, grain yield, and micronutrient content in straw and grain. Radish is one of the most taken examples of seed priming.

Examples of Biofortification

Fig: Golden Rice

1. Golden rice: Golden rice is High in beta-carotene, which is vital for children’s eyesight. This delivers vitamin A and aids in the recovery of partly blind children’s vision.
2. Sorghum: This crop is extremely low in nutrients. It was supplemented with lysine, which has been shown to be both productive and cost-effective.
3. Maise hybrid was enhanced with essential amino acids like lysine, tryptophan, etc.
4. Atlas 66 (wheat variety): This wheat variety was fortified with high protein content.
5. Spinach and Bathua: These herbs are a source of vitamin A. These were supplemented with high calcium and iron content.
6. Sweet potato, maize, and cassava are biofortified with provitamin A carotenoid.

Benefits of Biofortification

Below we have provided the benefits of biofortification:

1. Improved root penetration (deeper roots); enhanced nutrient absorption; advantages for soils low in trace metals.
2. Better Resource Efficiency: greater drought tolerance necessitates less irrigation; reduced chemical fertiliser usage.
3. Breeding for particular nutrient absorption feasibility.
4. Disease resistance has improved.
5. Increased yields.

Issues with Biofortification

Biofortification improves food quality, but it has several issues which need to be addressed:

1. Ethical, legal and Social Issues: There are groups of communities who oppose genetic engineering methods of biofortification because of their beliefs.
2. Compared to supplementation or dietary fortification techniques, fortified plants cannot supply as high a mineral and vitamin content.

Plant Tissue Culture

Plant tissue culture is a set of procedures for maintaining or growing plant cells, tissues, or organs in sterile circumstances on a known-composition nutrient culture medium. Micropropagation is a way of producing clones of a plant that is commonly utilised. Tissue culture is regarded as a critical technique for developing nations in the creation of disease-free, high-quality planting material as well as the quick manufacture of large numbers of homogeneous plants. Thousands of duplicates of a plant may be made in a short amount of time this manner.

Principle of Plant Tissue Culture

Plant tissue culture is a biotechnique based on the promise of in vitro manipulation of a plant’s organ, tissue, or cell to develop back into a whole plant. As a result, plant tissue culture is the cornerstone for plant genetic engineering and, in most cases, the bottleneck step.

Plant Tissue Culture Medium

Culture media is commercially available in powdered form. An ideal culture medium should contain macronutrients, micronutrients, vitamins, amino acids or nitrogen supplements, source(s) of carbon, undefined organic supplements, growth regulators and solidifying agents (agar), and pH regulators. The culture media should be prepared in a sterilised medium and in a sterilised container. 

Conditions for Plant Tissue Culture

Tissue culture should be performed in an aseptic environment. The tissues, equipment, culture media, and the room should be sterilised and contamination-free. All equipment should be sterilised in an autoclave at 15 lb pressure for 20—30 minutes at 120°C.

Steps of Tissue Culture

Fig: Steps of Plant Tissue Culture

Tissue Culture Method

Tissue culture is a procedure in which tiny pieces of a plant (ex-plants) are placed in nutritional media to allow them to function or develop. Plant fragments, maybe as little as a few cells, are inserted in an artificial growth medium to grow into new plants. The procedure involves following stages:

Initiation Phase: An ex-plant is a portion of a plant that has the ability to regenerate and give birth to the entire plant. It is important that the ex-plant is disease-and thoroughly sterilised before inoculation. Following the transfer, the mouth should be covered with a cap or a cotton plug, and the Petri dishes should be sealed with ‘Parafilm.’ It is also important to ensure that the plant tissue is appropriately exposed to the medium throughout the transfer.

Multiplication Phase: The sterilised explant is then placed in a medium containing a growth regulator and the necessary nutrients. They are in charge of cell division and multiplication. The term “callus” refers to an undifferentiated clump of cells.

Fig: Callus

Root Formation: The roots begin to develop. To start the root development process, plant growth hormones are given. As a result, we have a whole plantlet.

Shoot Formation: Plant growth hormones are administered to promote the creation of shoots, and the growth is monitored for a week.

Acclimatization: When the plant begins to grow, it is moved to a greenhouse where it may grow in a controlled environment. Finally, it is relocated to nurseries where it can flourish in a natural setting.

Tissue Culture Techniques

There are many tissue culture techniques. Following are some of the globally used tissue culture techniques:

1. Seed Culture: Ex-plants from an in-vitro generated plant are obtained in this culture and put into a laboratory where they flourish. To avoid tissue injury, the explant should be sterilised.
2. Embryo Culture: This entails the development of an embryo in vitro. An embryo is extracted from a live creature for this purpose. The technique can employ either a mature or immature embryo. Ripe seeds can be used to obtain mature embryos. Seeds that did not germinate are used to create immature embryos. The ovule, seed, or fruit has already been sterilised and does not require further sterilisation.
3. Callus Culture: A callus is a mass of dividing cells that is disorganised. The callus is obtained after the ex-plants have been grown in the correct medium. Organ differentiation follows the expansion of the callus. The culture is cultivated on a gel-like media that contains agar and particular nutrients necessary for cell development.
4. Organ Culture: Any plant organ, such as a sprout or a leaf, can be employed as an ex-plant in this procedure. Organ culture can be done using a variety of ways, including the plasma clot method, the raft method, the grid approach, and the agar gel method. This procedure is used to keep an organism’s structure and activities intact.
5. Meristem Culture: Meristem culture is a tissue culture method that utilises the apical meristem. Meristematic cells are developed cells that are either undifferentiated or incompletely differentiated. They are totipotent, meaning they can divide their cells indefinitely.
6. Protoplast Culture and somatic hybridisation: It’s a cell with no cell wall. The hanging-drop technique or micro-culture chambers can be used to cultivate a protoplast. A number of steps may be seen in protoplast culture, including cell wall formation, cell division, and plant regeneration.

Other Types include Pollen Culture, Anther Culture, Single Cell Culture, Suspension Culture, Somatic Embryogenesis, etc.

Advantage of Tissue Culture

Following are the various advantages of tissue culture technique:

1. Plantlets are created in a short span of time with a minimal quantity of plant tissue, and the new plants are disease-free.
2. The plants may be cultivated at any time of year, regardless of the season.
3. Tissue culture does not require a lot of areas to grow plants, and it speeds up the development of new types in the market. This technique is used to produce decorative plants like dahlias, chrysanthemums, orchids, and so on.

Applications of Tissue Culture

The applications of tissue culture are as follows:

1. Plant tissue culture is widely utilised in horticulture, forestry, and plant sciences.
2. Meristem and shoot culture are employed to grow huge numbers of identical individuals in the commercial cultivation of plants used as potting, landscaping, and florist subjects.
3. Tissue culture can be used by plant breeders to screen cells for desirable characteristics.

Summary

Breeding crops to boost their nutritional worth is known as biofortification. This can be achieved through three main approaches, namely transgenic, conventional, and agronomic, involving the use of biotechnology, crop breeding, and fertilisation strategies, respectively. Plant tissue culture is a set of procedures for maintaining or growing plant cells, tissues, or organs in sterile circumstances on a known-composition nutrient culture medium. Plant tissue culture is a biotechnique based on the promise of in vitro manipulation of a plant’s organ, tissue, or cell to develop back into a whole plant.

Plant tissue culture is of various types such as callus culture, embryo culture, protoplast culture etc. There are various advantages of plant tissue culture. Plantlets are created in a short span of time with a minimal quantity of plant tissue, and the new plants are disease-free. Plant tissue culture is widely utilised in horticulture, forestry, and plant sciences. Meristem and shoot culture are employed to grow huge numbers of identical individuals in the commercial cultivation of plants used as potting, landscaping, and florist subjects.

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FAQs on Biofortification and Plant Tissue Culture

Q.1. What is biofortification in plants?
Ans: Breeding crops to boost their nutritional worth is known as biofortification.

Q.2. Which part of a plant is used in plant tissue culture?
Ans: Almost all the parts of a plant can be used for tissue culture as long as it is healthy.

Q.3. Give three examples of biofortification.
Ans: Rice, beans, sweet potato, cassava, and legumes are biofortified with iron.

Q.4. Who discovered plant tissue culture?
Ans: Gottlieb Haberlandt discovered the plant tissue culture.

Q.5. Mention any three-culture media used in plant tissue culture.
Ans: Murashige and Skoog medium (MS medium), Gamborg medium (B5 medium), and White medium (W medium) are three-culture media used in plant tissue culture.