BACTERIA CRAVE TOXINS – SCIENCE & TECHNOLOGY

Bacteria crave toxins – science & technology

NEWS: Researchers at IIT-Bombay have identified two genera of bacteria, Pseudomonas and Acinetobacter, that have great potential in agriculture.

 

WHAT’S IN THE NEWS?

Background and Problem Context

  • Aromatic compounds, such as naphthalene, benzoate, and phthalates, are commonly used in industries producing pesticides, cosmetics, textiles, food preservatives, and other products.
  • Despite their utility, these compounds turn into environmental pollutants when they leach into the soil, causing significant harm.
  • Their harmful effects include:
    • Hindering seed germination.
    • Inhibiting plant growth and development.
    • Contaminating the food chain by poisoning plants, which eventually affects human health.
  • Removing these compounds from the soil is challenging because they are:
    • Chemically stable, making them resistant to breakdown.
    • Insoluble in water, which prevents them from being easily drained out.

 

Innovative Solution: Bacterial Approach

  • Researchers from IIT-Bombay, led by Prof. Prashant Phale and research scholar Sandeesh Papade, proposed an eco-friendly solution by leveraging soil bacteria.
  • They identified two genera of bacteria, Pseudomonas and Acinetobacter, that possess the ability to degrade these harmful aromatic compounds.
  • These bacteria naturally feed on aromatic compounds, breaking them down into simpler substances that are beneficial for plants and the soil.

 

Mechanism of Action

  • The bacteria metabolize harmful aromatic compounds in the soil and transform them into nutrients such as:
    • Phosphorus
    • Potassium
  • These nutrients are water-soluble, allowing plants to easily absorb them, unlike the original toxic aromatic compounds.
  • Additionally, the bacteria produce:
    • Siderophores: Specialized compounds that help plants absorb iron in environments with limited nutrients.
    • Indoleacetic acid (IAA): A plant growth hormone that promotes healthier and more vigorous growth in plants.

 

Dual Benefits of Bacteria

  1. Soil Remediation:
    • The bacteria act as natural soil cleaners, removing toxic aromatic pollutants and making the soil safer for plant growth.
  2. Soil Fertilization:
    • During the degradation process, the bacteria release essential nutrients that enrich the soil, enhancing its fertility and health.
    • They also improve plant resilience and support their growth through nutrient provision and hormone production.

 

Enhanced Effects of Consortium Use

  • The researchers observed that combining Pseudomonas and Acinetobacter produced significantly better results compared to using either bacteria alone.
  • When used together, the bacteria displayed:
    • Stronger plant growth-promoting effects.
    • Improved phytoprotection against the toxicity of aromatic compounds in the soil.
  • This synergy highlights the potential for creating biofertilizer-cum-biocontrol formulations that simultaneously clean the soil and boost crop health.

 

Additional Benefits

  • In addition to degrading toxic compounds, these bacteria demonstrated antifungal properties by attacking harmful fungi in the soil.
  • Their ability to survive and thrive under adverse conditions makes them highly adaptable. Key traits include:
    • Formation of biofilms, which enhance bacterial survival in harsh environments.
    • Resistance to fusaric acid, a compound toxic to plants.
    • Tolerance to salinity, allowing them to perform well even in saline soils.

 

Potential Applications and Future Research

  • Researchers plan to investigate the bacteria's performance under specific environmental stressors, such as drought and extreme temperatures.
  • Future work will focus on developing advanced biofertilizers that integrate multiple benefits, including soil cleaning, enhanced plant growth, and stress resistance.
  • These bacteria could also play a critical role in sustainable agriculture, reducing dependency on chemical fertilizers and pesticides while promoting eco-friendly practices.

 

Bacteria that helps in agriculture:

Nitrogen-Fixing Bacteria

These bacteria convert atmospheric nitrogen into a form usable by plants (ammonia).

  • Rhizobium: Forms symbiotic relationships with leguminous plants, fixing nitrogen in root nodules.
  • Azotobacter: Free-living nitrogen-fixing bacteria found in soil.
  • Azospirillum: Associative nitrogen-fixing bacteria, especially beneficial for cereals and grasses.
  • Frankia: Fixes nitrogen in symbiotic association with actinorhizal plants (e.g., alder trees).

 

Phosphate-Solubilizing Bacteria (PSB)

These bacteria solubilize insoluble phosphates into forms plants can absorb.

  • Bacillus megaterium
  • Pseudomonas fluorescens
  • Burkholderia cepacia
  • Acinetobacter

 

Potassium-Solubilizing Bacteria (KSB)

These bacteria help make potassium available to plants.

  • Bacillus mucilaginosus
  • Bacillus edaphicus
  • Paenibacillus spp.

 

Plant Growth-Promoting Rhizobacteria (PGPR)

These bacteria enhance plant growth by producing growth hormones, siderophores, and enzymes.

  • Pseudomonas fluorescens: Produces siderophores, protects against pathogens, and promotes growth.
  • Bacillus subtilis: Promotes growth and provides biocontrol against plant pathogens.
  • Serratia marcescens: Produces enzymes and helps plants absorb nutrients.

 

Biocontrol Bacteria

These bacteria protect plants from pathogens by producing antibiotics, competing for nutrients, or inducing systemic resistance.

  • Bacillus thuringiensis (Bt): Produces toxins harmful to pests and is widely used as a biopesticide.
  • Pseudomonas putida: Suppresses plant pathogens by producing antifungal compounds.
  • Streptomyces spp.: Produces antibiotics and combats soil-borne pathogens.

 

Sulfur-Oxidizing Bacteria

These bacteria convert sulfur into sulfate, a form accessible to plants.

  • Thiobacillus: Important for sulfur cycling in soil.

 

Organic Matter Decomposing Bacteria

These bacteria help decompose organic material, releasing nutrients into the soil.

  • Cellulomonas: Breaks down cellulose in plant residues.
  • Bacillus spp.: Decomposes organic matter efficiently.

 

 

Stress-Tolerant Bacteria

These bacteria help plants cope with environmental stresses such as drought, salinity, and extreme temperatures.

  • Pseudomonas stutzeri: Enhances drought resistance.
  • Bacillus amyloliquefaciens: Improves salinity tolerance and supports plant growth under stress.

 

Iron-Solubilizing Bacteria

These bacteria produce siderophores to chelate iron and make it available to plants.

  • Pseudomonas spp.
  • Acinetobacter spp.

 

Methanotrophic Bacteria

These bacteria reduce methane emissions from paddy fields and contribute to sustainable agriculture.

  • Methylobacterium: Promotes plant growth and reduces greenhouse gas emissions.

These beneficial bacteria are integral to sustainable agriculture, improving soil fertility, protecting crops from diseases, and reducing reliance on chemical fertilizers and pesticides.

 

Significance

This study provides a sustainable and innovative solution to two critical agricultural challenges: removing soil pollutants and improving crop productivity. By utilizing the natural capabilities of bacteria, the approach offers an eco-friendly alternative to traditional methods, enhancing soil health and contributing to long-term agricultural sustainability.

 

Source: https://www.thehindubusinessline.com/business-tech/bacteria-that-crave-toxins/article69093062.ece