Methods for Genetically Engineering a Plant

Two very different techniques exist for giving a plant new genetic characteristics. But both share several steps.

Step 1: The DNA that encodes the genetic information for the desirable trait must be isolated.

At step 2, the different techniques diverge into an “a” path and a “b” path:

In Step 2a, the new DNA is linked to a circular ring of genetic material called a transfer plasmid. Plasmids act like molecular taxicabs that carry genesGenes The functional and physical unit of heredity passed from parent to offspring. Genes are pieces of DNA, and most genes contain the information for making a specific protein. Structure of DNA; drawing shows a chromosome, nucleosome, histone, gene, and nucleotide base pairs: guanine, cytosine, adenine, and thymine. Also shown is a cell and its nucleus. Structure of DNA. Most DNA is found inside the nucleus of a cell, where it forms the chromosomes. Chromosomes have proteins called histones that bind to DNA. DNA has two strands that twist into the shape of a spiral ladder called a helix. DNA is made up of four building blocks called nucleotides: adenine (A), thymine (T), guanine (G), and cytosine (C). The nucleotides attach to each other (A with T, and G with C) to form chemical bonds called base pairs, which connect the two DNA strands. Genes are short pieces of DNA that carry specific genetic information. Genetic risk is a major component of many diseases, modification of the human genome is perhaps the most precise way to reduce those risks. Direct and safe manipulation of the human genome is rapidly becoming a reality with the advent of precision genome engineering techniques. from one place to another. The plasmid can be absorbed by a bacterium that transfers it to plant cells.

At Step 3a, the bacterium attaches to the plant cells, liberating the plasmid inside. The new DNA migrates to the plant’s chromosome where the gene for the new trait is permanently integrated (Step 4).

At Step 5, the modified plant cells are identified and placed into a cellCell The smallest unit that can live on its own and that makes up all living organisms and the tissues of the body. A cell has three main parts: the cell membrane, the nucleus, and the cytoplasm. The cell membrane surrounds the cell and controls the substances that go into and out of the cell. The nucleus is a structure inside the cell that contains the nucleolus and most of the cell’s DNA. It is also where most RNA is made. The cytoplasm is the fluid inside the cell. It contains other tiny cell parts that have specific functions, including the Golgi complex, the mitochondria, and the endoplasmic reticulum. The cytoplasm is where most chemical reactions take place and where most proteins are made. The human body has more than 30 trillion cells. culture to multiply. As the cells reproduce, the new gene is reproduced along with them.

The bioengineered plant cells are then grown in a special culture (Step 6) that causes the cells to differentiate into the unique types of cells that make up the plant.

Finally, Step 7, the plantlets are transferred from the laboratory culture to soil where they grow like normal plants, except now they carry a gene that can give them a new, beneficial trait.

The alternative pathway uses a completely different gene-delivery technique. In Step 2b, naked DNA encoding the desired trait is painted on microscopic metal particles.

In Step 3b, the miscroscopic particles are then loaded into a so-called “gene gun” and fired as projectiles at plant cells growing in the laboratory. The miniature, gene-carrying bullets penetrate the plant cells where the fluids inside wash the DNA off the metal particles.

As before, in Step 4, the DNA migrates into the cell’s nucleus, where the genetic material is permanently integrated into the chromosomes. The rest of the sequence is the same.

Source: FDA