What is the important for knowing the diversity of nitrogen fixation gene?

Question

What is the important for knowing the diversity of nitrogen fixation gene?

Answer 1

Nitrogen fixation or Nif  is carried out by nitrogenase, a complex enzyme, that has a number of genes involved not just one gene. Each gene potentially has allelic variation. Variation allows a population to inhabit a greater range of habitat types. Knowing the alleles that exist for any given gene shows us the limits that the gene can operate under. This means one population can have genetically diverging lineages within it. In legume symbiotic rhyzobacteria there can be allelic types that associate with specific plants but not others. There is a genetically selected factor in the plant bacteria association and the way the nitrogenase functions may be an important part of this association.

Answer 2

It is interesting from an evolutionary point of view.  Most only work in anaerobic conditions like they were before life created all the O2 on the earth.  It is the main way that nitrogen is added to the food chain so it would be useful to know which organism have it.