Crops have always been plagued by insects, disease, nutrient-poor soil and drought. Now, it seems that one small part of the problem may be solved. One of the critical nutrients that plants require to grow is nitrogen. Nitrogen must be ‘fixed’ in order to turn Nitrogen from the air into a usable format, like ammonia, which can be used as a nutrient.  Legumes have been known to be particularly efficient at this process.  For years, crop rotation strategies included planting legumes in order to maintain a supply of usable nitrogen in the soil.

In fact, beans are not fixing nitrogen at all. Rather it is the bacteria that exist in a symbiotic relationship within certain nodules located on the plants’ roots.

A new study performed by Stanford researchers discovered the legume’s efficiency in nitrogen fixation is due to the presence of a specific signal, which allows them to control the behavior of the bacteria living symbiotically in their nodules.  The signal triggers the bacteria to begin converting nitrogen into ammonia.  The researchers identified the gene that is involved in inducing this pathway, so that now, scientists may alter efficiency of the bacteria’s nitrogen production by increasing or decreasing the amount of trigger signals the plant sends out.

The hope is that by increasing the efficiency of natural nitrogen fixation in legume plants, there will be a decreased need for chemical fertilizers to create more nutrient rich soils. This decrease in chemical fertilizers, if implemented in a wide-spread fashion, will greatly impact the chemical footprint that farmers leave on their surroundings.

Discussion question: What are some kinds of legumes that could be altered to implement this efficiency increase?

News Article: http://www.sciencedaily.com/releases/2010/03/100301091552.htm
Journal Article: http://www.sciencemag.org/cgi/content/abstract/327/5969/1126