Arizona researchers separated plant roots by a 3 mm gap, then added fungus; it carried water between the plants and helped connected plants grow more than grew twice as much

Plants beneath the soil might be less self-sufficient than they may seem. But they have the ability to get connected by tiny fungal threads that create hidden pathways underground, allowing resources to move between plants. In a study published in 2024, scientists from Northern Arizona University tested how strong plant-fungal connections may be by examining whether dark septate endophytes could link two plants separated by a small physical gap.

The experiment was conducted by scientists from Northern Arizona University who separated two plants by a 3-millimeter gap. The gap prevented direct root contact, but after adding a type of fungus called a dark septate endophyte (DSE), the scientists found that the fungus grew across the space and formed a connection between the plants. They reported that the fungus was transferring water between the plants and that plants connected through the fungal network showed greater growth than plants without the connection.

A hidden partnership beneath the soil


Decades of research have shown that fungi can establish relationships with plant roots. Indeed, there are many fungi living near or within plant roots that help in the extraction of nutrients in return for the energy produced by photosynthesis. Yet, most attention has been given to mycorrhizal fungi, which are famous for their networks. The research conducted in Arizona concentrated on another type of fungi - dark septate endophytes - which are widespread in different plants throughout the world. These fungi are especially interesting because they are common in harsh environments, including areas where water is limited. Researchers wanted to understand whether these underground organisms could do more than simply live alongside plants.

A tiny gap with a surprising result

To test the connection, researchers placed pairs of plants in separate chambers. The plants were close enough for the fungus to potentially reach across, but the 3-millimeter air gap prevented direct root contact. After infecting one plant with the fungus, researchers saw the development of thin fungal structures called hyphae between the two plants. These thin filaments formed a channel between the two plants. The team used a water marker to track movement and later detected labeled water in the leaves of the connected plant, showing that water could move through the fungal connection between the two plants.

Why water sharing matters for plants

Water availability can determine whether plants survive, especially in dry regions such as the American Southwest. During drought, plants often compete for limited water underground, but fungal connections may provide another way for them to access resources. The study revealed that plants with the fungal network showed higher growth rates than those plants without the fungal network. It indicates that the fungus might play a part in how plants adapt to their environment. The discovery could help scientists better understand natural ecosystems where plants survive in places with little rainfall. The findings suggest that some plants may benefit from underground fungal connections.

The role of fungi in plant survival

Moreover, this research transforms scientists’ perception of the nature of soil. The seemingly unassuming layer of soil turns out to be a very complicated environment where lots of biological processes take place. Microscopic mycelia of fungi can connect different living beings together, and all this remains unseen at first glance. For farmers and conservation scientists, the findings provide new information about how fungal networks may influence plant growth and water movement during drought conditions. The study adds to research exploring how underground relationships contribute to plant survival in stressful environments.