(3)Transgenic Plants Notes

Bacillus thuringiensis (Bt)

A Gram-positive soil bacterium that produces insecticidal proteins, specifically crystal proteins (Cry toxins), during sporulation.

BT toxin

Also known as Cry toxins, these are crystalline proteins produced by Bacillus thuringiensis that have insecticidal properties. These toxins are activated in the insect gut and bind to specific receptors, leading to pore formation, cell lysis, and ultimately, insect death.

Parasporal crystal

A protein crystal inclusion produced by Bacillus thuringiensis during sporulation, containing protoxins that are precursors to the active BT toxins.

Cowpea Trypsin Inhibitor (CpTI)

A protease inhibitor that prevents insects from hydrolyzing proteins, leading to starvation. It interferes with insect digestion by inhibiting proteases, reducing nutrient uptake.

Gossypol

A natural toxin produced by cotton plants, inhibiting dehydrogenase enzymes in insects. Insects produce cytochrome P450 monooxygenase to inactivate gossypol, but this can be targeted by RNAi.

Herbicide

A type of pesticide used to kill unwanted plants (weeds) that compete with crops for resources.

EPSPS (5-enolpyruvylshikimate-3-phosphate synthase)

An enzyme in plants and bacteria that synthesizes aromatic amino acids. It is the target of glyphosate, a common herbicide.

Glyphosate

A broad-spectrum herbicide that inhibits EPSPS, thus blocking the synthesis of aromatic amino acids necessary for plant growth. Commonly known as Roundup.

Roundup Ready

Crops that are genetically engineered to be resistant to glyphosate. They produce a modified EPSPS enzyme that is not inhibited by glyphosate.

Dicamba (3,6-dichloro-2-methoxybenzoic acid)

A herbicide used to control broadleaf weeds. It mimics high levels of the plant hormone indole-3-acetic acid.

Dicamba monooxygenase (DMO)

An enzyme that converts dicamba into a non-herbicidal form, 3,6-dichlorosalicylic acid, providing resistance to plants.

Salicylic acid (SA)

A signaling molecule in plants that activates the expression of pathogenesis-related (PR) proteins, leading to systemic acquired resistance.

Pathogenesis-related (PR) proteins

Plant proteins induced upon pathogen attack, exhibiting antimicrobial activities. Examples include β-1,3-glucanases and chitinases.

Glucanase

A pathogenesis-related (PR) protein that degrades glucans, components of fungal cell walls, thus providing defense against fungal pathogens (specifically β-1,3-glucanases).

Chitinase

A pathogenesis-related (PR) protein that degrades chitin, a component of fungal cell walls and insect exoskeletons, thus providing defense against fungal pathogens and insects.

Thaumatin-like proteins

are plant proteins, belonging to the PR-5 family of pathogenesis-related proteins (PR proteins), induced during infection or stress conditions.

NPR1 gene

Encodes a regulatory protein controlling PR protein expression. Activated by salicylic acid, overexpression of NPR1 leads to broad-spectrum disease resistance.

Trehalose

A sugar consisting of two molecules of alpha-glucose that protects cells from drought and salt damage, often increased via genetic manipulation.

Golden Rice

Genetically engineered rice to produce beta-carotene (provitamin A) in the endosperm, designed to combat vitamin A deficiency.

Lignin

The second most abundant organic compound