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Rhizobium Microbiology Science Learning Educative Presentation
 

Rhizobium Microbiology Science Learning Educative Presentation

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A creative way to learn about the bacteria Rhizobium with a touch of Bollywood. For young, science minds. This was a part of my college curriculum as I am studying Microbiology Hons.

A creative way to learn about the bacteria Rhizobium with a touch of Bollywood. For young, science minds. This was a part of my college curriculum as I am studying Microbiology Hons.

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    Rhizobium Microbiology Science Learning Educative Presentation Rhizobium Microbiology Science Learning Educative Presentation Presentation Transcript

    • MICROBIOLOGY PRESENTATION TOPIC RHIZOBIUM BY RASHIKA SOOD
    • What is Rhizobium?
    • Rhizobium are symbiotic diazotrophs (prokaryotic organisms that carry out dinitrogen fixation) that form a endoymbiotic association with legumes.
    • • Rhizobium is a genus of Gram negative Soil Bacteria. • They are non sporing bacteria. •Rod shaped cells. 0.5-0.9 um x 1.2-3.0 um in size.
    • WHO DISCOVERED RHIZOBIUM?
    • Martinus Beijerinck (1851–1931) was one of the great general microbiologists who made fundamental contributions to microbial ecology and many other fields. He isolated the aerobic nitrogen-fixing bacterium Bacillus radicicola a root nodule bacterium also capable of fixing nitrogen (later named Rhizobium)
    • Rhizobium can be found in Root nodules of legumes.
    • Legumes are herbaceous woody plants that produce seeds in pods; examples of legumes include peas, beans, alfalfa, vetches, clovers, lupines, trefoils, locust, and mimosa. (fabaceae) It is difficult to isolate rhizobium from the soil.. Rhizobium are predominantly aerobic chemoorganotrophs and grow well in the presence of oxygen and utilize a wide range of relatively simple carbohydrates and amino compounds.
    • What is Rhizobium’s Nutrition?
    • The rhizobia doesn’t grow wellwell on the peptone media used routinely. Yeast mannitol (YM) is the most generally suitable for their growth. Optimal growth of most strains occurs at a temperature range of 25- 30° C and at a pH of 6.0- 7.0 Colonies are white pigmented. Colonies are circular, convex, semi- translucent, raised and mucilaginous. Despite their usual aerobic metabolism, many strains are able to grow well under microaerophillic conditions at oxygen tensions of less than 0.1 atm.
    • Mobile by a single polar flagellum or two to six peritrichous flagella. MOBILITY
    • PROTECTION OF RHIZOBIUM
    • •Rhizobium is surrounded by a slimy capsule made of exopolysaccharide, which protects it from drying out. And also helps the bacterium stick to root hairs during various stages of its life cycle.
    • •Rhizobium contains nitrogenase, which is irreversibly damaged by exposure to oxygen. But Rhizobium is aerobic and requires large amount of energy for Nitrogen fixation. It solves this “oxygen dilemma” by protecting the nitrogenase through Oxygen Scavenging Chemicals, specifically Leghaemoglobin a transport protein which effectively removes oxygen from module. It also has exceptionally fast and efficient aerobic metabolism so very little Oxygen is stockpiled.
    • Host plant Bacterial symbiont Alfalfa Rhizobium meliloti Clover Rhizobium trifolii Soybean Bradyrhizobium japonicum Beans Rhizobium phaseoli Pea Rhizobium leguminosarum Sesbania Azorhizobium caulinodans Some other Rhizobium sp. From Rhizobiaceae- R. Cellulosilyticum R. daejeonense R. etli R. galegae R. gallicum R. giardinii R. hainanense R. huautlenseR. Indigoferae R. leguminosarum R. loessense R. lupini R. lusitanum R. mongolense R. miluonense R. sullae R. tropici R. undicola R. yanglingense Both plant and bacterial factors determine specificity Rhizobium-legume symbioses
    • The Nodulation Process 1. Chemical recognition of roots and Rhizobium 2. Root hair curling 3. Formation of infection thread 4. Invasion of roots by Rhizobia 5. cortical cell divisions and formation of nodule tissue 6. Bacteria fix nitrogen which is transferred to plant cells in exchange for fixed carbon
    • RhizosphereFlavonoids nod-gene inducers Nod-factor Chemical recognition of roots and rhizobium. Very early event.
    • Tip of a clover root hair. The rhizobia shown here are clustered on the surface of the root. Soon they will start to invade the roots and begin a symbiotic partnership that will benefit both organisms.
    • 2. Root hair curling. Root hair curls to trap the colony of rhizobium. 3. Formation of infection thread to penetrate root cortex and reach vascular tissue.
    • Pea plants inoculated with R. leguminosarum carrying the plasmid pHC60 that constitutively expresses green fluorescenst protein (GFP). Curled root hairs (arrows) of pea plant. Infection thread (green fluorescence) reaching the base of the root hair in plants.
    • 3. Invasion of roots by Rhizobia 4. cortical cell divisions and formation of nodule tissue
    • Bacteria converts to bacteroids and begin to form nitrogenase enzyme. Rhizobium fixes nitrogen which is transferred to plant cells in exchange for fixed carbon
    • Hope you Enjoyed N’ learnt something! 