Fungal Love: How Pectin Enzymes Bring Trees and Soil Together 

Deep in the heart of the forest, a mysterious dance unfolds. The roots of the trees twist and turn, reaching out to embrace the soil beneath them. But they're not alone. Tiny fungal threads, known as hyphae, weave their way through the earth, seeking out the tree roots. Together, these unlikely partners form a symbiotic relationship, known as an ectomycorrhizal (ECM) symbiosis.

But how do these unlikely partners come together? It turns out, it all starts with a molecule called pectin. Pectin acts like a glue, holding the cells of the tree roots together. But for the fungal hyphae to infiltrate the roots and form the Hartig Net, the pectin needs to be loosened. And that's where the fungal enzymes come in.

We have discovered that a specific enzyme found in the fungus Laccaria bicolor, called LbPME1, plays a critical role in this process. By modifying the pectin and making it less sticky, LbPME1 allows the hyphae to slip into the roots and form the Hartig Net, facilitating nutrient exchange between the partners.

But the story doesn't end there. We went on to discover that the deeper the Hartig Net, the stronger the partnership between the tree roots and the fungus. And it all comes down to the amount of LbPME1 present. Too little, and the relationship is shallow. Too much, and the Hartig Net becomes deeper, allowing for a stronger partnership.

Author: Jamil Chowdhury

7 July 2022.