August 25, 2025
Agriculture
Plant Growth-Promoting Bacteria: Mechanisms and Applications
With the increasing human population, global food production at the current rate would be insufficient to meet the dietary needs of all people in the near future.
It is, therefore, crucial to enhance agricultural productivity over the next few decades.
Also, a sustainable and environmentally friendly approach is necessary to prevent the exploitation of natural resources.
Plant Growth-Promoting Bacteria, or PGPB, can help achieve the dual goal of crop productivity and sustainable agriculture.
Plant Growth Promoting Bacteria
It is well known today that soil is replete with different forms of microorganisms.
Of these, bacteria are the most common.
According to scientific data, soil hosts millions of bacteria. Soil conditions, including temperature, moisture, salinity, and the types of plants present in the soil, influence it.
It is essential to note that bacteria are highly concentrated around the plant’s roots.
This narrow region in the soil is known as the rhizosphere.
The plant growth-promoting bacteria belong to the beneficial and heterogeneous group of microorganisms in the rhizosphere that are capable of stimulating plant growth.
Moreover, it protects against abiotic stresses and diseases by controlling or inhibiting the activity of pathogens.
Furthermore, it also improves soil structure.
Depending on the plant species and strains, the influence of bacteria on plant growth and its mechanism differ.
The mechanisms are broadly classified as Direct and Indirect.
The indirect mechanism involves the activation of defense mechanisms against diseases, also known as induced systemic resistance (ISR).
Direct Mechanism
A direct mechanism includes plant growth by increasing the nutrient supply and hormones to the plant.
- Biofertilizer – Biofertilizer consists of microorganisms that are applied to seeds, plant surfaces, and soil to enhance the supply of nutrients and promote plant growth. Different microorganism present in bio-fertilizer boosts soil fertility, the natural soil nutrient cycle, and soil organic matter availability. PGPB is one of the most widely used beneficial bacteria today.
- Nitrogen fixation – Nitrogen fixation is the process by which atmospheric nitrogen is converted into a usable form that changes into ammonia. It is the basic building block of plants. Microorganisms in nature carry out biological nitrogen fixation. A wide variety of plant growth-promoting bacterial species helps promote plant growth and yield by enhancing nitrogen uptake in plants.
- Phosphate Solubilization – Phosphorus is an essential nutrient for optimal plant growth. However, phosphorus is available mostly in insoluble forms. The PGPB facilitates the solubilization of inorganic phosphorus and the mineralization of organic phosphorus. As phosphate fertilizer is too expensive for farmers, using plant growth-promoting bacteria as inoculum for phosphate uptake is advantageous. Iron is another nutrient that is scarce in soil. PGPB can produce compounds known as siderophores, which contain ferric iron. Roots can utilize this for plant growth.
- Phytohormones – Phytohormones play a major role in the natural growth of plants. Different processes, such as leaf formation, flower development, and fruit ripening, are regulated and determined by it. Due to various environmental factors, plants are subjected to stress. This is where PGPB can alter phytohormone levels and help in its response to stress.
Indirect Mechanism
Induced Systemic Resistance – Induced systemic resistance is a phenomenon or form of defense mechanism in plants that activates when a pathogenic agent infects the plant.
It helps in controlling diseases. The inducing bacteria trigger a reaction in the roots, which acts as a signal that reaches all parts of the plant, inducing systemic resistance.
Today, agriculture relies heavily on chemical inputs to boost plant growth and protect crops.
However, the overuse of chemicals can lead to unexpected environmental problems.
Therefore, there is an urgent need to use plant growth-promoting solutions for sustainable agriculture without any environmental issues.
Organica Biotech is a leading company that offers a wide range of solutions for sustainable agriculture.
Its MagicGro range of products includes MagicGro DripSol, MagicGro Nemacare, MagicGro PSB, and other products that boost crop development and improve plant immunity and vigor sustainably.
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