Genetic engineering is used to develop stress-tolerant plants by introducing or modifying specific genes that help them survive and grow under adverse environmental conditions such as drought, salinity, heat, cold, and heavy metal stress. Through precise manipulation of plant DNA, scientists can enhance natural defense mechanisms and improve overall plant performance under stress.
Here are the main ways genetic engineering contributes to stress tolerance in plants:
- Introduction of Stress-Responsive Genes:
Genes from other plants, microorganisms, or even animals that are known to confer tolerance to stress can be inserted into crop plants. For example, genes encoding heat shock proteins (HSPs) or late embryogenesis abundant (LEA) proteins help plants survive drought and temperature extremes. - Enhanced Osmoprotectant Production:
Genetically engineered plants can be made to produce higher amounts of osmoprotectants like proline, glycine betaine, and trehalose. These molecules help maintain cell structure and enzyme activity during dehydration or salt stress. - Improved Antioxidant Defense:
Under stress, plants generate harmful reactive oxygen species (ROS). By overexpressing antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX), genetic engineering helps plants neutralize oxidative damage. - Modification of Stress Signaling Pathways:
Genes involved in abscisic acid (ABA) signaling and other hormonal pathways can be engineered to activate stress responses more effectively. This enables plants to close stomata, conserve water, and adjust metabolism during drought or heat stress. - Ion Transport and Homeostasis:
To tolerate salinity, genes controlling ion transporters (like HKT, NHX, and SOS genes) are introduced or modified. These help plants maintain a balance between sodium and potassium ions, protecting cellular function under salt stress. - Transcription Factor Engineering:
Transcription factors such as DREB, NAC, WRKY, and MYB are engineered to regulate multiple stress-related genes simultaneously, improving tolerance to drought, cold, or salinity. - Expression of Protective Proteins:
Genetic engineering can induce the synthesis of chaperone proteins, antifreeze proteins, or dehydrins that stabilize proteins and membranes under extreme environmental stress.
In summary, genetic engineering equips plants with enhanced physiological and biochemical defense mechanisms to withstand environmental stresses, ensuring better crop yield, stability, and food security in changing climatic conditions.