Biofertilizer Production

Sustainable agriculture via Biofertilizer application

Biofertilizer Production

Lesson: Indole-3-Acetic Acid Producing Microorganisms

What is IAA?

    • IAA is the main auxin (phytohormone) in plants. It regulates plant growth and developmental processes such as cell division and elongation, tissue differentiation. It governs root elongation and branching [1,2]. It regulates response to pathogens.
    • In addition to plants, Indole-3-Acetic Acid is also produced by microorganisms found in rhizospheric soil and by endophytes of plants.
    • Structure of IAA can be seen at the following link: https://pubchem.ncbi.nlm.nih.gov/compound/Indole-3-acetic-acid#section=2D-Structure

What is the importance of IAA Producing Microorganisms ?

    • If such organisms are included as components of biofertilizers, application of such biofertilizers to seeds or agricultural soil can enhance the growth of the plants/ crops.

What are the examples of Indole-3-Acetic Acid Producing Microorganisms?

    • Indole-3-Acetic Acid ProducingMicroorganisms are of the following types:
    • Bacteria: e.g. Bacillus sp., Pseudomonas sp., Azotobacter sp. and Rhizobium sp.
    • Some plant pathogenic fungi produce IAA: e.g. Fusariun oxysporum, Colletotrichum gloeosporioides, Pleurotus ostreatusand Nectria pterospermi;
    • Some mycorrhizal fungi and yeasts also produce IAA.

On which nutrient media would you grow them?

    • They can be grown on various media but their activity is detected [1,2] using:
    • Nutrient broth supplemented with 5 mg/ mL tryptophan.

What is the composition of Nutrient broth medium ?

    • Composition of Nutrient broth medium [5]:
      • Ingredients Gms / Litre: Peptone 10.0, Beef extract 10.0, Sodium chloride 5.0 The pH of the medium is adjusted to 7.0-7.2.
      • For Nutrient agar, Agar-agar 25 g/ L is added to the medium before autoclaving it.

How do you sterilize these media?

    • Autoclave the medium at 15 PSI (ie lbs/ in2), at 121.6°C for 15-20 min. Cool the medium to room temperature before use. Pour agar containing media into sterile petri plates when they are moderately hot ie 55-60°C. Allow the media to solidify or set.

How would you detect and estimate IAA produced [2]?

Production of IAA is determined by colorimetric method of Gordon & Weber[6]. The cultures are inoculated in Nutrient broth supplemented with 5 mg/ mL tryptophan, incubated at 30 °C for 24 h under shaking conditions. The broth is then centrifuged at 10,000 rpm for 10 min at 4°C to get cell free supernatant. Two mL of Salkowski’s reagent (2 ml 0.5M FeCl3 added to 98 ml 35% perchloric acid) is added to 1mL of cell free supernatant thus obtained. It is incubated in the dark for 30 min at room temperature. Development of pink color indicates production of IAA. The intensity of pink color that develops is measured at a wavelength of 540 nm and the concentration of IAA produced is estimated by comparison with the standard dose response curve for IAA (10 μg/ mL to 100 μg/ mL) estimation by the method of Gordon & Weber.

Since Salkowski reagent also detects and gives a pink color with indole, indole-3-butyric acid and skatole, the production of IAA can be confirmed by Thin Layer Chromatography (TLC)[2]. 

References

  1. Desai, P & Sayyed, Riyaz (2011). Antifungal And Phytohormone Production Ability Of Plant Growth Promoting Rhizobacteria Associated With The Rhizosphere Of Sugarcane. Journal of Microbial World. 13:112-116.
  2. Sneha Ogale, Karan Singh Yadav and Shrutika Navale. Screening of endophytic bacteria from the pharmacologically important medicinal plant Gloriosa superbafor their multiple plant growth promoting properties. The Pharma Innovation. 2018; 7(1): 208-214.
  3. Mohite. ‘Isolation and characterization of indole acetic acid (IAA) producing bacteria from rhizospheric soil and its effect on plant growth’. Journal of Soil Science and Plant Nutrition , 2013, 13(3), 638-649.
  4. Ogale S., Kulkarni A., Nichit S.and Shah D. ‘Screening Of Endophytes Of Gloriosa superbaFor Their Plant Growth Promoting Potential And Optimization Of Indole-3-Acetic Acid Production. World Journal of Pharmaceutical Research’. 2018. 7 (4): 145-155.
  5. http://www.himedialabs.com/TD/MM244
  6. Gordon SA and Weber RP. Colorimetric Estimation of Indole acetic Acid. Plant Physiology, 1951; 26(1): 192-195.

12 thoughts on “Biofertilizer Production”

  1. Sir, I want to join this. I am assistant professor in microbiology. Whats the process to join

    1. Dear Sir,
      The course is being finalized and soon to be launched. I shall inform you once it is launched so that you and your colleagues and students can join.
      Thanks and regards,
      Mrs. Sneha Ogale

  2. I am working as Assistant professor microbiology (chb).. Interested in this activity..

    1. Dear Madam,
      The course is being finalized and soon to be launched. I shall inform you once it is launched so that you, your colleagues and students can join.
      Thanks and regards,
      Mrs. Sneha Ogale

  3. First of all congratulations Ma’am.
    It’s a very good initiative and need of society.
    Ma’am Please let me know once you launch this course.
    Will share the link among my friends and those who are interested.

    1. Hello Shahen,
      Thank you so much! The course is being finalized and soon to be launched. I shall inform you once it is launched so that you can share the link.
      Thanks and regards,
      Mrs. Sneha Ogale

  4. Congratulations Madam for taking this initiative.
    Let me know that how will I know whether I m registered or not?

    1. Dear Sir,
      Thank you for your interest. Welcome aboard. I am adding you to the whatsapp group of registered participants in order to coordinate your participation.
      Thanks and regards,
      Sneha Ogale

  5. Congratulations mam and thank you for lunching such an open resource.
    It will be helpful to farmer’s & I am one of them, eager to join.
    Please let me know when & how to join.

    1. Dear Milind,
      Welcome aboard. I am adding you to the whatsapp group of registered participants in order to coordinate your participation.
      Thanks and regards,
      Sneha Ogale

  6. Dear Sneha Ogale,

    My name is Chau – greenhouse grower in Vietnam.
    I’d like to take your Biofertilizer production course online. I’ve tried to sign up at Edmodo website using the group code written in this page. Howerver, it wasn’t a correct code.
    Please advise how to register for this course.

    Thank you very much for your sharing and helping.

    Regards,

    Chau

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