Plant Metabolic Engineering Essentials Quiz

Metabolism in Crops

• Metabolites are intermediate products of cellular metabolism catalyzed by various enzymes that naturally occur within cells.
• Metabolites can be categorized into two types: primary metabolites and secondary metabolites.

Primary Metabolites

• Primary metabolites are chemical compounds produced during growth and development processes.
• Examples of primary metabolites include carbohydrates, proteins, lipids, and nucleic acids.
• They have physiological functions and are directly involved in normal growth, development, and reproduction.
• They are typically present in many organisms/cells and are also referred to as central metabolites.
• In higher plants, primary metabolites are often concentrated in seeds and vegetative storage organs and are needed for physiological development.

Secondary Metabolites

• Secondary metabolites are produced by plants but have no physiological functions.
• They have ecological importance and play a role in plant protection and defense against herbivores and other organisms.
• Examples of secondary metabolites include alkaloids, terpenoids, and lignins.
• They are often restricted to a narrow set of species within a phylogenetic group.

Metabolic Engineering

• Metabolic engineering involves the redirection of one or more enzymatic reactions to produce new compounds in an organism, improve the production of existing compounds, or mediate the degradation of compounds.
• It requires the development of basic biotechnological technologies such as cloning, promoter analysis, protein targeting, plant transformation, and genetic metabolism.

Plant Metabolism and Modern Agriculture

• Humans have exploited the plant synthesizing capability and developed agricultural practices to meet basic needs for food, fiber, energy, chemicals, and medicine.
• Plants can synthesize 5,000 to 25,000 different compounds.
• More than 100,000 metabolites have been identified in the plant kingdom.
• Plant metabolites provide energy, vitamins, and antioxidants, and are sources of nutritional and nutraceuticals for humans.

Plant Metabolism Engineering

• Plant metabolism engineering involves the direct improvement of product formation or cellular properties through the modification of specific biochemical reactions or the introduction of new ones using recombinant DNA technology.
• Why plants? They are cheaper and readily available, easy to grow, and provide a eukaryotic system.
• Plant cells are highly compartmentalized.

Strategies for Plant Metabolic Engineering

• Eliminating the activity of specific enzymes in a pathway using strategies such as identifying mutant genes, knocking out gene function, and interfering with protein function.
• Increasing flux of existing pathways using strategies such as manipulating the activity of "rate-limiting" steps, metabolic flux analysis and modeling, and expressing multiple genes in plants.

Plants as Bioreactors

• Plants can be used as bioreactors to produce a variety of products such as antibodies, edible vaccines, polymers, and pharmaceutical drugs.