Plant Microbe Symbiosis (Springer Books)

Nitrogen is a vital element necessary for all living organisms (plants,
microbes, and animals) for the production of nucleic acids, proteins, and other bio-
molecules in which nitrogen is needed. Nitrogen is the most abundant gas in the
atmosphere of planet Earth, almost 79%. Even in its highest availability, living
organisms cannot utilize this gaseous form, unless and until it is in fixed form,
which is the reduced form, where it combines with hydrogen and forms ammonia.
Photosynthetic plants use this fixed nitrogen to make organic matter, and the
phytoproteins that are produced enter into the food chain. On death or during
decomposition, microorganisms catabolize the proteins present in the body of dead
organisms, fecal wastes, and other organic matter, releasing ammonium ions and
forming the primary mechanism of the nitrogen cycle. Microbes exist everywhere, in
soil, air, water, and even in extreme conditions, and they also need nutrients for their
survival. Of all types of bacteria, some form the complex association known as
symbiosis with other living organisms, which can be commensalism, parasitism,
mutualism, predation, amensalism, or competition, proto-cooperation between bac-
teria and other organisms.