Genetically modified (GM) crops are developed using biotechnology to introduce specific genes that give plants desirable traits such as pest resistance, drought tolerance, or improved nutrition. The process involves several scientific steps that allow scientists to modify the plant’s genetic material in a precise and controlled way.
- Identification of the Desired Gene:
The first step is to identify and isolate a gene responsible for a useful trait. This gene may come from a bacterium, another plant, or even an animal. For example, the Bt gene from the bacterium Bacillus thuringiensis is used because it produces a protein toxic to certain insect pests. - Gene Isolation and Modification:
Once the target gene is identified, it is isolated using molecular biology techniques. Sometimes, scientists modify the gene slightly to ensure it functions properly in the new plant. Regulatory sequences like promoters and terminators are also added to control how and when the gene is expressed. - Gene Insertion into Plant Cells:
The modified gene is inserted into plant cells using one of two main methods:- Agrobacterium-mediated transformation: A natural soil bacterium called Agrobacterium tumefaciens carries the desired gene into the plant’s DNA.
- Gene gun (biolistic method): Tiny particles coated with DNA are shot into plant cells, and some of the DNA integrates into the plant genome.
- Selection of Transformed Cells:
After transformation, only a few plant cells successfully take up the new gene. To identify these, scientists use marker genes (like antibiotic or herbicide resistance) that help select the modified cells. These transformed cells are then grown in a culture medium. - Plant Regeneration through Tissue Culture:
The genetically modified cells are encouraged to grow into complete plants using plant tissue culture techniques. This is done under sterile conditions with growth hormones that help the cells develop roots and shoots. - Verification and Testing:
The new plants are tested in laboratories to confirm the presence and proper functioning of the inserted gene. Molecular tests like PCR and sequencing are used to ensure accuracy. Plants are then evaluated for their performance under greenhouse and field conditions. - Field Trials and Safety Assessment:
GM plants undergo extensive testing to check for food safety, environmental impact, and stability of the introduced trait. Regulatory agencies review these data before approval for commercial cultivation. - Commercial Production:
Once approved, the GM crop is grown and distributed to farmers. The new trait is stably inherited by future generations through normal breeding.
Genetically modified crops have been developed for various purposes such as pest resistance (Bt cotton), herbicide tolerance (Roundup Ready soybeans), improved nutrition (Golden Rice with vitamin A), and stress tolerance (drought-resistant maize).
In summary, GM crops are created by isolating and transferring beneficial genes into plant genomes using biotechnology tools. This precise process allows scientists to develop crops with improved productivity, resistance, and nutritional quality, contributing to sustainable agriculture and global food security.