Environmental factors have a strong influence on gene expression in plants, helping them adjust growth, development, and survival according to changing surroundings.
Plants cannot move, so they respond to the environment by turning certain genes on or off. This allows them to adapt to conditions like light, temperature, water, and soil nutrients.
Here are the main environmental factors that affect gene expression in plants:
- Light
- Light controls many plant processes such as photosynthesis, seed germination, and flowering.
- Special light receptors (like phytochromes and cryptochromes) detect light and activate genes that control leaf development and chlorophyll production.
- For example, in sunlight, genes for photosynthetic proteins are turned on, while in darkness, they are turned off.
- Temperature
- Changes in temperature can activate or repress certain genes.
- Cold temperatures trigger cold-responsive (COR) genes that protect cells from freezing.
- High temperatures activate heat shock proteins (HSPs) that prevent damage to other proteins.
- Water availability
- Drought stress turns on genes that produce abscisic acid (ABA) and proteins that help retain water or protect cells from dehydration.
- Flooding can also activate genes that help roots survive low oxygen conditions.
- Nutrients and soil conditions
- Lack or excess of nutrients such as nitrogen, phosphorus, or iron can change gene activity.
- For example, nitrogen deficiency activates genes that improve nitrogen uptake or fix nitrogen more efficiently.
- Pathogens and pests
- When attacked by bacteria, fungi, or insects, plants activate defense genes that produce protective compounds, enzymes, or structural barriers.
- These responses are often controlled by hormones like salicylic acid, jasmonic acid, and ethylene.
- Stress factors (like salinity or pollution)
- High salt levels or toxins can alter gene expression to help the plant detoxify or balance water and ions.
In short, environmental factors affect gene expression in plants by activating or silencing specific genes. This allows plants to adjust their physiology and metabolism to survive and thrive in changing conditions.