Field Notes
In this debut delivery of refugia, we peer into the fascinating world of symbiosis as a framework for building novel conservation efforts.
Mycorrhizal Medicine
Research of Note: Zhao, Y., Cartabia, A., Lalaymia, I. et al. Arbuscular mycorrhizal fungi and production of secondary metabolites in medicinal plants. Mycorrhiza 32, 221–256 (2022). https://doi.org/10.1007/s00572-022-01079-0
Summary: Featured in a 2022 volume of the Mycorrhiza journal , this comprehensive literature review brings readers up-to-date research on the nuanced relationships between diverse strains of arbuscular mycorrhizal fungi and the production of secondary metabolites found in 81 medicinal plant species. Some of the more recognizable species examined include:
Turmeric (Curcuma longa)
Lemon Balm (Melissa officinalis)
St. John’s Wort (Hypericum perforatum)
Ashwagandha (Withania somnifera)
Authors Zhao, Y., Cartabia, A., Lalaymia, I. et al. delineate many of the complexities behind secondary metabolite production in plants and also provide readers with a nicely organized table which includes the following information:
Plant species and family
AMF strain(s) used
Commonly used plant parts for therapeutic purposes
Chemical compounds (secondary metabolites) responsible for therapeutic measures
Medicinal uses of plants
Increase or decrease in chemical compounds in distinct plant parts (roots, stems, leaves and flowers)
Increase or decrease in above and below ground biomass overall
Readers here on refugia who explore this literature review further will discover useful insights as to how diverse AMF strains impacted the 81 selected plant species in all of the above parameters.
Among the many thought provoking findings from this review, the most critical is as follows,
“Only a few medicinal plant species were inoculated with AMF present in the soil native to those plants, while the vast majority were inoculated with commercial inoculants”1
By now, most soil curious readers, gardeners, and beyond will be well acquainted with AMF. The wonder and importance of beneficial soil fungi has been a popular, trending topic in the wide constellation of regenerative agriculture circles for more than a few years - and for good reason. A mini AMF refresher is provided below. The following passage first appeared in an article authored by Kousch for ACRES, USA and the Colorado Department of Agriculture:
Arbuscular mycorrhizal fungi (AMF) play an integral role in fostering plant health by orchestrating chemical exchanges, resistance to abiotic and biotic stressors, physical structuring, and nutrient cycles in the soil. AMF belong to the phylum Glomeromycota, an ancient fungi, and create a mutualistic symbiotic relationship with up to 80 percent of terrestrial plants.
When AMF intiates a relationship with a plant, it colonizes the roots of compatible plant species with structures called arbuscules. Once established, AMF serves as a conduit between a plant and the substrate surrounding the rhizosphere. The host plant supplies AMF with up to 20 percent of plant-fixed carbon in exchange for water and nutrients, such as phosphorus, delivered to the plant via an ingenious network of branching structures known as hyphae.
Hyphae are the filamentous extensions, analogous to root hairs, of AMF. As AMF colonizes a plant root, hyphae rapidly reproduce and spread outward into the rhizosphere. As the body of hyphae expands, its role is to absorb nutrients and water from the soil and transport them back to its host plant. While this dance of exchanges is occurring between fungi and plant, something quite fascinating is also happening, which is the development and dispersal of a glycoprotein called glomalin. Glomalin is the glue that holds soil together. In the vast world of soil ecology, glomalin is the must-have tool for engineering tilth, stability, and resilience.2
Market Significance:
We need to continue examining native AMF strains in native, wild, and field-grown conditions. Studies such as the following are doing just that:
Shao, Y., Jiang, S., Peng, H., Li, H., Li, P., Jiang, R., Fang, W., Chen, T., Jiang, G., Yang, T., Nambeesan, S. U., Xu, Y., & Dong, C. (2023). Indigenous and commercial isolates of arbuscular mycorrhizal fungi display differential effects in Pyrus betulaefolia roots and elicit divergent transcriptomic and metabolomic responses. Frontiers in plant science, 13, 1040134. https://doi.org/10.3389/fpls.2022.1040134
These native AMF relationships will be foundational to the next suite of Nature Based Solutions (NBS) and beyond that — these will be the relationships that will inform what can grow - and where - when drought or deluge or both become the only drivers behind market signals of any significance - and some might argue - already are.
Consider that the global dietary supplements (of which herbal botanicals are a significant subset) “market size was valued at USD 86.77 billion in 2023” (Fortune Business Insights) and only slated to continue to climb.3 Studies indicate that 30,000 different species of plants are used medicinally worldwide (Sustainable Herbs Initative) 4Professionals in the herbal industry, from clinicians to CPG folks to growers well recognize that many of these medicinal species are very difficult to propagate and cultivate domestically based on a wide number of edaphic and terrestrial factors. These are wild plants. And even so - the number of medicinal plants that we can cultivate - and that confer significant ecological benefits to grow sites - from soil health to biodiversity metrics - is also considerable.
We are referring to globally consumed herbs like chamomile, ashwagandha, calendula, and hundreds more. Plants that not only can be cultivated in the US, but plants that often thrive in the margins - is less than desirable soil - and plants that represent a largely untapped market for US regenerative/organic-standard growers and novel questions for restoration agriculture and conservation practitioners to consider.
Further intersections to explore:
Plant phytoremediation properties, NRCS CRP field practices, and the presence of synthetic fertilizers, herbicides, and pesticides
Moisture gradients, native AMF populations, and nutrient levels
Soil health benefits conferred by isolated and identified root exudates of medicinal plants
In producing this literature review, Zhao, Y., Cartabia, A., Lalaymia, I. et al. shared with the world of medicinal plant studies - a sturdy, strong launching point.
Until next week - here’s a preview of what’s come (subscribe below for your weekly field notes delivery):
The Salty Siren Song of Bacteria
“Before you can understand how and why, you have to understand who,” Brawley says. “This is a very rich source of who is where”5
and
The Mercy of Roots
Enter prairie strips. Iconic, beautiful, columns of color - teeming with plant diversity - and underground - filtering toxic nutrient loads, rebuilding soil aggregation, all through the persistent power of perennial roots.