Watch Bacteria Hitch a Ride Along the “Fungal Highway”

You may have heard the term: the living soil before Now you can actually see it in remarkable detail.

This amazing video was recently posted to the Scientific American website. It shows microscopic bacteria (Pseudomonas putida) travelling along the surface of a fungus (Cunninghamella elegans) in real time. The fungus in this video is growing over the surface of Potato Dextrose Agar.

You can see how these bacteria are taking advantage of the water membrane that surrounds the fungus to move further, faster and more efficiently than they ever could on their own. This process (dubbed the “fungal highway” hypothesis by researchers) allows bacteria to get around air pockets and dry particles in the soil that would otherwise impede their momentum.

The video captures another process called cytoplasmic streaming. This is how fungi move resources (water, nutrients) within its hyphae. The same process is also seen with fungi such as mycorrhizal fungi.

The biological highway is also observed when you place a non-mobile bacteria (ex. Rhizobium leguminosarum biovar viciae) and a mycorrhizal fungus (Glomus intraradices). The exudates of the mycorrhizal hyphae promote an immense multiplication of the bacteria along the hyphae, and bring it further onto the root system providing more locations for nodule formation on the root system.

Enjoy the ride!