|MadSci Network: Biochemistry|
Some early reports suggested that mycorrhizal fungi could fix atmospheric nitrogen and pass this on to the associated plant. However, it is now generally accepted that this is not true. It appears that the biological fixation of diatomic nitrogen is only carried out by prokaryotes, e.g. Rhizobium, Acetobacter, and various cyanobacteria. These prokaryotes in turn can associate with mycorrhizal fungi, which in turn associate with the host plant, passing the fixed nitrogen along this chain. Because of this complex rhizosphere, engineering rapeseed (canola, Brassica napus) with a reduce nitrogen fertilizer requirement would really involve the engineering of the entire [Brassica – mycorrhizal fungus – prokaryotic nitrogen fixer] system to produce the appropriate interactions. This is certainly at this point not an easy problem, requiring a better knowledge of these interaction than we presently have.
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