Plant Biotechnology and Genetic Engineering

These flashcards cover key concepts in plant biotechnology, including plant tissue culture, methods of plant regeneration, the role of genetic engineering, and specific examples like Golden Rice and FlavrSavr tomatoes.

What is plant tissue culture?

The cultivation and maintenance of plant material in vitro, which aids in studying plant biology and producing valuable compounds.

What are the three phases involved in plant tissue culture?

1. Isolation of plant tissue from its usual environment 2. Use of aseptic techniques to obtain clean material 3. Culture and maintenance of material in a controlled environment.

Name the main types of plant culture established in vitro.

1. Callus culture 2. Cell suspension culture 3. Protoplast culture 4. Organ culture 5. Embryo culture 6. Anther culture 7. Shoot tip and meristem culture 8. Axillary branching.

What is callus culture?

Cultivation of an undifferentiated mass of plant cells produced at wound sites, which can be induced to differentiate by adjusting hormone ratios.

What are essential components of a culture medium?

Mineral salts, vitamins, organic components, plant growth regulators, carbon source, and gelling agents.

What is somatic embryogenesis?

A method of plant regeneration that involves forming embryo-like structures from somatic tissues.

What are the two types of somatic embryogenesis?

1. Direct somatic embryogenesis (bypasses callus phase) 2. Indirect somatic embryogenesis (involves callus formation before embryo development).

What is the purpose of including reporter genes in genetic constructs?

Reporter genes help monitor the transformation process and the expression levels of introduced genes.

What are the advantages of chloroplast transformation over nuclear transformation?

High expression levels, genetic containment, precise DNA integration, absence of gene silencing, and use of natural promoters.

What is the FlavrSavr tomato?

The first genetically modified tomato designed for improved shelf life by downregulating the expression of polygalacturonase.

What mechanisms does Bacillus thuringiensis employ to kill insects?

It produces crystal proteins that are ingested by insects, which then disrupt gut membranes, leading to the insect's death.

What are some limitations of chloroplast transformation?

Technical difficulty, limited protein export, lack of glycosylation systems, and potential for heteroplasmy.

What is the significance of Agrobacterium tumefaciens in plant genetic engineering?

It is used to transfer genes into plants via T-DNA from its Ti plasmid.

What health risks are associated with herbicide-resistant crops?

The development of 'superweeds', gene transfer to wild relatives, and increased overall herbicide use.

What is the mechanism by which glyphosate resistance is achieved in GM crops?

By introducing a modified EPSPS gene that does not bind glyphosate, allowing the plant to produce essential amino acids.

Describe the Golden Rice project.

It aims to alleviate vitamin A deficiency by engineering rice to produce beta-carotene in its grains.

What are the concerns regarding the use of genetically modified organisms (GMOs)?

Environmental risks, health safety, company accountability, and reduced biodiversity.

What is required to keep plant cultures aseptic?

Strict maintenance under aseptic conditions to prevent contamination from various pathogens.

What is the role of phytohormones in plant tissue culture?

Phytohormones regulate growth and development, influencing cell division, elongation, and differentiation.