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Siderophores produced by bioagents in controlling of plant diseases


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Siderophores produced by bioagents in controlling of plant diseases

  1. 1. Cl O Siderophores produced by bioagents in controlling of plant diseases
  2. 2. PL PATH 515 Submitted By; Manjunatha o M.Sc.Agri Submitted to; Dr.Bharati N Bhat Sr, scientist Plant Pathology SRTC Hyderabad -30
  3. 3. Contents  Iron – An Important Element  Siderophores  Siderophores of bacteria  Case study  How siderophores will form???  Role of siderophores in controlling plant pathogens  Bacteria used as BCA  Conclusion  Refereces
  4. 4. Iron – An Important Element  4th most abundant element in the world  An important nutrient for the body.  Helps with growth and development in the body, especially in children.  Iron is forever cycled from a liver storehouse in a protein called ferritin.
  5. 5. The Paradox of the Limited Abundance of Iron Lack “iron” in such an iron-abundant planet ? •Extremely limited bioavailability. •Bacteria battles to acquire iron to obtain nutrients that to help contribute to growth
  6. 6. Siderophores  Siderophores is a Greek word means "iron carrier”.  They are small, high-affinity iron chelating compounds secreted by micro organisms such as bacteria, fungi and grasses .  Siderophores are amongst the strongest soluble Fe3+ binding agents known.  Siderophores usually form a stable, hexadentate, octahedral complex with Fe3+  Kloepper et al.(1980) were the first to demonstrate the imp. of Siderophores
  7. 7. Structure  Siderophores are amongst the strongest binders to Fe3+ known, with enterobactin being one of the strongest of these.  Siderophores are produced by both pathogenic and non-pathogenic bacteria in different environments.  Siderophores can be defined as small peptidic molecules containing side chains and functional groups that can provide a high-affinity set of ligands to coordinate ferric ions .
  8. 8. Siderophores of bacteria  Pseudobactin Pseudomonas sp  Schizokein Bacillus subtilis
  9. 9. Others  Pseudomonas fluorescens – ferribactin  Pseudomonas cepacia - cepabactin  Pseudomonas aeruginosa - pyoverdin
  10. 10. Case study Role of fluorescent siderophore production in biological control of pythium ultimum by a pseudomonas fluorescens strain - Joyce E Loper
  11. 11.  pseudomonas fluorescens migula strain 3551 isolated from cotton rhizosphere soil, cotton from seed colonization and pre-emergence damping off.  The role of fluorescent siderophore production by strain 3551 in antagonism against P. ultimum was investigated  14 non fluorescent (Flu-) Tn5 insertion mutants of P. fluorescens 3551 obtained following matings with E-coli SM 10
  12. 12.  Strain 3551 grew on iron deficient medium, whereas the 14 (Flu- )derivative strains did not. These 2 strains evaluated for colonization by P. ultimum.  3551 decreased the colonization of cotton seed by P. ultimum and increased the seedling emergence. (Flu-) derivative strains did not.
  13. 13. Conclusion  fluorescent siderophore production by pseudomonas fluorescens strain 3551 contributes, but did not account for all of its antagonistic activity against P. ultimum.
  14. 14. How siderophores will form??? Iron is often insoluble (oxides, hydroxides) Cells produce siderophores Iron binds to siderophore complex Siderophore binds to recognition site on cell Iron is reduced (Fe3+ into Fe2+) Iron is taken up by the cell.
  15. 15. Siderophore receptor site on cell Siderophore Outside the Cell Inside the Cell Fe3+
  16. 16. Siderophore receptor site on cell Outside the Cell Fe3+ Fe3+ Inside the Cell
  17. 17. Siderophore receptor site on cell Fe3+ Fe3+ Siderophore Outside the Cell Fe3+ Inside the Cell
  18. 18. Role of siderophores in controlling plant pathogens  To satisfy nutritional requirements of iron, microorganisms have evolved highly specific pathways that employ low molecular weight iron chelators termed siderophores.  Siderophores are secreted to solubilize iron from their surrounding environments.  forming a complex ferric-siderophore that can move by diffusion and be returned to the cell surface.
  19. 19.  Siderophores can chelate ferric ion with high affinity.  its solubilization and extraction from most mineral or organic complexes.  In aerobic conditions at physiological pH, the reduced ferrous (Fe2+) form is unstable.  Fe2+ is readily oxidized to the oxidized ferric (Fe3+) form.  Fe3+ occurs as a poorly soluble iron hydroxide basically unavailable to biological systems.
  20. 20. Bacteria used as BCA  Psuedomonas fluroscence  Psuedomonas putida  Bacillus subtilis :- Bacillibactin
  21. 21.  Among most of the bacterial siderophores studied, those produced by pseudomonads are known for their high affinity to the ferric ion.  The potent siderophore, pyoverdin, can inhibit the growth of bacteria and fungi that present less potent siderophores in iron-depleted media in vitro.  P. putida B10 strain against Fusarium oxysporum.  But this suppression was lost when the soil was replenished with iron, a condition that represses the production of iron chelators by
  22. 22. conclusion  Recent studies have demonstrated the suppression of soil-borne fungal pathogens through the release of iron-chelating siderophores by fluorescent pseudomonads, rendering it unavailable to other organisms.
  23. 23. References  International Journal of Modern Plant & Animal Sciences.  Department of Soils and Water Resource Management, Faculty of Agriculture, Rajarata University of Sri Lanka.  The Society for Biotechnology, Japan. Published by Elsevier B.V
  24. 24. Reviews  Anderson, A. J., Tari, P. H., and Tepper, C. S. 1988. Genetic studies on the role of an agglutinin in root colonization by Pseudomonas putida. Appl. Environ. Microbiol.  Anderson, A. J., Tari, P. H., and Tepper, C. S. 1988. Genetic studies on the role of an agglutinin in root colonization by Pseudomonas putida. Appl. Environ. Microbiol.  Tari, P.H., and Anderson, A. J. 1988. Fusarium wilt suppression and agglutinability of Pseudomonas putida. Appl. Environ. Microbiol.  Jacobsen, B. J., Zidack, N. K., and Larson, B. J. 2004. The role of Bacillus-based biological control agents in integrated pest management systems: Plant diseases. Phytopathology.  Kloepper J W, Ryu C M, Zhang S. (2004). Induce systemic resistance and promotionplant growth by Bacillus spp. Phytopathology.  Kloepper J W, Leong J, Teintze M, Schroth M N. (1980). Pseudomonas siderophores: A mechanism explaining disease suppression in soils. Current Microbiology.
  25. 25. Any questions ?
  26. 26. THANK YOU