Evidence for common fungal networks among plants formed by a Dark Septate Endophyte in Sorghum bicolor

Fungal connections among plants, popularly known as the “wood wide web,” captured the interest of scientific and public audiences because these connections may facilitate increased growth, improved survival, nutrient transfer, and communication among plants. Research on these fungal networks has focused almost exclusively on known plant symbionts called mycorrhizal fungi. However, many non-mycorrhizal fungi also form ecologically important associations with plants. If non-mycorrhizal fungi such as Dark Septate Endophytes (DSEs) can form common networks among plants, then fungal connections among plants are likely more complex and prevalent than previously thought. In this study, we ask whether a common DSE can form hyphal connections between plants, improve plant biomass, and move water between them. Using a lab system with donor and receiver plants, we find that DSE hyphae crossed air gaps to physically connect plants. Receiver plants that were connected to a fungal network had higher biomass than those that were not. A water-soluble dye injected into donor plant leaves was detected in receiver leaves, but only when plants were connected via the fungal network. These results provide the first lab-based evidence that common non-mycorrhizal networks can occur and suggest that fungal networks among plants may extend beyond mycorrhizal fungi.