Role of microbes in nitrogen fixation

That's all about role of microbes in nitrogen fixation
Symbiotic Relationship of Microbes and plants

1. microbe-plant interaction Rhizobia nodule Pest control disease phyllosphere Symbiotic N2 fixation rhizosphere Plant tolerance mycorrhizae Stem module

2. Nitrogen fixation

3. Rhizobium Rod shaped,motile.etc Non sporing , non-acid fast Rhizobia are susceptible to antibiotics, bacteriophages, fungicides, herbicides etc. Named after the host plant Pea – Rhizobium leguminosarum Beans – R. phaseoli Soyabeans – R. japonicum Lupins – R. lupini Two types of Rhizobium- Bradyrhizobium – slow growing species Rhizobium - fast growing species

4. Site and mechanism of nitrogen fixation in nodules

5. LHb combines with O 2  to form oxyleghaemoglobin ( OLHb ) and makes it available at the surface of bacterial membrane Fe-protein interacts with ATP and Mg ++ , and Mo-Fe-protein catalyses the reduction of N 2  to NH 3 , H +  to H 2   Ferredoxin act as electron transfer during N 2  fixation This enzyme complex gets energy from Mg ATP produce in bacterial respiration. N2 + 16 ATP + 8e- + 10H+ 2NH+4 + H+2 + 16ADP + 16Pi N2 FIXATION IN ROOT NODULES

6. Fig: N 2 fixation in root nodules of legumes N 2 fixation in bacteria

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