Linking soil health to human health: Arbuscular mycorrhizae play a key role in plant uptake of the antioxidant ergothioneine from soils

Abstract

Societal Impact Statement Evidence has emerged that the antioxidant ergothioneine may be important in preventing many inflammatory diseases in humans. However, ergothioneine is not produced by humans or plants and is only made by fungi and some bacteria in soils. As such, humans get ergothioneine from eating fungi (mushrooms) or plants that take it up from the soil. In this study, we found that growing plants with beneficial fungi called arbuscular mycorrhizal fungi increased the amount of ergothioneine in plant tissues. This suggests that promoting agricultural practices that maintain healthy populations of beneficial soil fungi may improve the nutritional quality of crops. Summary The amino acid ergothioneine (ERGO) has recently gained attention as an antioxidant that benefits human health. ERGO is produced by fungi and mycobacteria in soils and is acquired only from diet. The mechanism by which ERGO is transferred from soil to plant is unknown. Recent work has shown that tillage reduces the amount of ERGO in crops. As tillage also reduces arbuscular mycorrhizal fungi (AMF) populations, we examined the relationship between AMF and plant ERGO uptake. We grew asparagus, black beans, wheat, and oats with a variety of single and mixed species AMF inocula and compared ERGO levels of these plants to plants that were uninoculated. Mycorrhizal inoculation enhanced ERGO content across all plants. There was a positive correlation between AMF colonization level and plant ERGO content. AMF appear to be important mediators of plant ERGO uptake. Future research is needed to identify the mechanism that leads to higher ERGO in plants colonized by AMF in order to promote farming practices that enhance AMF populations and increase crop ERGO concentration in field settings.

Inoculation of black turtle beans (Phaseolus vulgaris) with mycorrhizal fungi increases the nutritional quality of seeds

“…It is possible that this phenomenon is the result of competition for access to root surface area between AMF species that have a lower C cost of nutrient acquisition with less efficient AMF species, but this hypothesis requires further testing which may employ the strategy of inoculating hosts with combinations of individual AMF species with equal spore densities. Additionally, we previously reported that seven of these AMF treatments, including the mixed‐species treatment, increased black bean uptake of the compound ergothioneine from soils, an antioxidant synthesized by fungi that is gaining traction as a potential human health vitamin (Beelman et al., 2020, 2022; Carrara, Lehotay, et al., 2023; Carrara, Reddivari, et al., 2023). Therefore, future studies would benefit by measuring additional nutritional quality indicators in controlled AMF studies.…”

“…This observed variability in the benefits of mycorrhizal inoculation on host plants is likely due to a range in the plant C costs of nutrient return across AMF species. The most cost‐effective AMF species, or the AMF species with the highest nutrient acquisition efficiency, provides the greatest benefit to plant fitness (Carrara & Heller, 2022; Carrara et al., 2023; Carrara et al., 2023; Kiers et al., 2011; Van't Padje et al., 2021; Werner & Kiers, 2015). As such, trials that assess plant responses to inoculation with a variety of individual AMF species are a promising avenue toward developing host‐targeted inocula that can enhance nutrient uptake and crop yield to the greatest extent.…”

A Mushroom-Derived Compound That Could Change Your Life: Ergothioneine

“…Fungi, particularly mycorrhizal fungi, play a pivotal role as the primary contributors to ergothioneine entering the food chain [26]. It seems that mycorrhizal fungi, along with other soil fungi, transfer or produce ergothioneine in plants through their symbiotic or close relationships with the roots of grain and vegetable plants [10,29]. This process underscores the interconnected nature of ecosystems, where fungi act as conduits for essential compounds, enriching the nutritional profile of plants and subsequently contributing to the overall dietary intake of ergothioneine in humans.…”

“…It transports essential nutrients and water elements back to the root. Recent research by [29] indicates that mycorrhizal inoculation and higher level of mycorrhizal colonization significantly increased the level of ergothioneine in asparagus, black beans, oats, and wheat. The colonization of mycorrhizal fungi increased the ergothioneine levels in these crops several fold in most cases.…”