When you think of bacteria, what comes to mind? Do you think of unclean hands and Petri dishes with little round colonies? I personally think about my experiences with laboratory bacteria, which I have cultured in various flasks and on different plates. But bacteria are so much more than pesky little germs or tools for research.
Although bacteria can be dangerous and cause illness and infection (and many certainly do!), they are also beneficial to the human body and to the environment; some special species of bacteria can “fix” nitrogen into forms that plants are able to utilize, which can survive and thrive in the roots of the plants themselves, in structures called root nodules. Some species of plants that rely on such nitrogen-fixing bacteria include legumes, like soybeans, alfalfa, and other species, and this relationship between the bacteria and the plants, who both benefit from the arrangement, is an example of a symbiotic relationship (for another example of a symbiotic relationship, see my recent post Coral Calamity). Nitrogen fixation by bacteria is actually a very important step in the global nitrogen cycle (1).
Source: https://www.britannica.com/science/nitrogen-cycle
Nitrogen exists in the atmosphere as nitrogen gas (N2). Nitrogen-fixing bacteria, like the species Rhizobium, fix N2 into ammonia (NH3), an ingredient commonly found in plant fertilizer (2). Ammonia is the biologically “preferred” state of nitrogen because it can more easily be used for its important biological functions; all DNA is made from nitrogenous (nitrogen-containing) bases, and nitrogen is required for the formation of peptide bonds, the type of bond that makes up all proteins and peptides (3). Thus, nitrogen is a key ingredient for life, and nitrogen-fixing bacteria are bac-terrific!
Works Cited
(1) https://www.britannica.com/science/nitrogen-fixing-bacteria
(2) https://www.mda.state.mn.us/pesticide-fertilizer/anhydrous-ammonia
Science with Mandy 
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