Uncovering the Economic Genius of Fungi: How Mycorrhizae Revolutionized Plant Life and Hold Lessons for Modern Trade Networks

In 1997, at the age of 19, Toby Kiers gained entry to the prestigious tropical research institute on Barro Colorado Island, located within the Panama Canal. Here, she embarked on a year-long fellowship where she discovered mycorrhizae, microscopic fungi that form intricate underground networks with local trees.

Mycorrhizae are found globally, and if the length of all the mycorrhizae present in a hectare of grassland were stretched end to end, they would span numerous Amazon Rivers. It was this seemingly invisible world that captivated Kiers and became her lifelong area of study.

Initially thought to be parasites due to their ability to penetrate plant roots, mycorrhizae were later found to engage in mutually beneficial relationships with plants. They provide the plants with essential nutrients like phosphorus and nitrogen in exchange for sugars and fats derived from carbon in the air.

This discovery led Kiers to question whether plants and fungi could be seen as shrewd economic actors, operating within a fluctuating marketplace where resources are exchanged based on supply and demand. While this is not her primary focus, she believes that fungi may exhibit more efficient economic behavior than humans, a notion that has garnered interest from some of the world’s leading corporations.

Over the past few decades, researchers have come to appreciate the intelligence exhibited by plants, which communicate with each other and adapt their defenses in response to predators. It is estimated that 70-90% of plants engage in symbiotic relationships akin to sharing resources with their partners.

However, Kiers argues that this perspective underestimates the potential for manipulation within these partnerships. If plants and fungi have been exchanging resources for millions of years, they must have strategies in place to prevent exploitation. This, she believes, presents an economic challenge.

In order to study partner choice within the plant and fungus kingdoms, Kiers conducted experiments using legume plants, which partner with microbes residing on their roots. The legumes provide sugars; the microbes offer fixed nitrogen in return. Kiers found that when a microbe did not supply necessary nutrients, the legume would “sanction” it by limiting its access to oxygen, resulting in failure to reproduce.

Moving on to her area of special interest, mycorrhizae, Kiers investigated whether plants and fungi also exercise partner choice and respond to market conditions. Experiments suggest that they do, as plants in full sun traded more resources with fungi due to their higher sugar content, demonstrating a response to supply and demand.

With the aid of quantum-dot nanoparticles and advanced imaging technology, Kiers’s team has been able to track trading patterns between plants and fungi and observe their adaptive behavior in response to changes in resource availability. These findings highlight the importance of such trade, as it played a crucial role in shaping the world as we know it by enabling plants to expand from oceans onto land.

Today, mycorrhizae are still responsible for sequestering vast amounts of carbon dioxide each year – an equivalent of one-third of fossil fuel emissions – prompting Kiers and her colleagues to found the organization SPUN with a mission to protect these underground networks.

Specialization and trade have proven to be powerful strategies for increasing productivity, with plants that abstain from such partnerships being rare exceptions. As Kiers reflects on her research into fungi’s subterranean economy, she expresses skepticism towards centralized resource control and decision-making in human society.

She views the behavior of mycorrhizae as an example of decentralized decision-making, noting similarities between simple decisions made by humans in response to supply and demand and the adaptive behavior exhibited by fungi in their underground networks.

While Kiers cautions against equating human trade with the bartering between plants and fungi, she believes there is much to be learned from their decentralized infrastructure development and trading systems when considering the future of artificial intelligence and global supply chains.

Kiers’s research has also provided insights into why it can be challenging to keep houseplants alive – due to our interference with their natural access to trade networks. She emphasizes the importance of intact networks in offering resilience and adaptability.