Most Plants Depend On A Fungi-Bacteria Relationship We’ve Been Overlooking

Agricultural scientists may ignore a symbolic relationship necessary for the success of food production. Its discovery could lead to the possibility of replacing artificial fertilizers to increase crop growth, which could lead to unintended consequences. Botanists have been aware for a century of the role that bacteria play in determining the nitrogen in the roots of some plant families, which we see as a necessary step in enriching the soil sufficiently to support abundance.

The role of symbiotic fungi, which similarly occupy the root systems of plants, has known for almost a long time but much less studied despite being more extensive in practice. Now, it has revealed that when plants form a partnership with these fungi, they are bacteria that play a hidden role and actually enter a trachea. The Arab Scholar mycorrhizal Fungus (AMF) found in 72 percent of the land at the base of the tree mostly associated with other fungi. Fungi are more able to access nitrogen and phosphorus in the soil than plants and as a result extract these important nutrients and send them to their hosts.

As well as being a place to live, plants provide fatty acids in exchange. Maria Harrison, a professor at the Boyce Thompson Institute, wondered where the AM fungi were getting these nutrients from, as they lacked the enzyme to free them from the complex organic molecules that represent the mainland reservoir.

Harrison and colleagues studied bacteria in filament-like roots known as hyphae, which the AMF projects into the ground to propagate them. In the ISME Journal, they reported the presence of bacteria in the hyphae of two fungal species found in the surrounding soil. Harrison said in a statement, “Like human intestines or plant roots, AM fungi have their own unique microbiomes.” 

Harrison is looking for further confirmation but is considering whether it is helping bacteria remove nutrients from the soil, especially important phosphates. His theory is that bacteria break down organic molecules in the soil by previous generations of plants and animals. It makes phosphorus – and possibly other nutrients – available for the fungus, some using its own and giving place to the rest of the plants. “If we are right, enriching the soil for some of these bacteria can increase crop yields and ultimately reduce the need for conventional fertilizers with their associated costs and environmental impact,” Harrison said.