Fine-Tuned Fungi Rescue Plants from Toxic Pollutants - Reasons to Believe

Fungi get a bad rap. They're most often labeled as parasites. They are such in the sense that they depend upon photosynthetic plants for the food they need. However, by that definition, all animals are parasites too. In truth, fungi fulfill many crucial roles for the survival and thriving of other life-forms.

Fungal Ecosystem Contributions
Fungi are the principal decomposers of dead organisms. They are vital to recycling nutrients in dead plant, animal, and microbial tissues for the benefit of living organisms. Without this continual recycling, life would be short-lived and humans would never have been able to inhabit Earth.

Most fungal species are symbionts; that is, they engage in symbiosis. Symbiosis is defined as the living together of unlike species for the benefit of one or both species. Symbiosis can be obligate, meaning one or more symbionts critically depend on each other for survival, or facultative or optional, meaning the two species can survive independently. Symbiosis can also be conjunctive, where the two species are physically attached to one another, or disjunctive, where the two species are not attached to one another.

The most widespread of all symbiotic relationships is that between arbuscular mycorrhizal fungi (AMF) and vascular plants (plants with xylem and phloem that act as a hydraulic system to bring water and nutrients up from the soil to the leaves and food from the leaves to the rest of the plant). AMF attach to the roots of vascular plants. The plants provide sugars and lipids to the AMF, which are crucial for their survival and growth. The AMF harvest carbon, nitrogen, sulfur, and phosphorus compounds from the soil and transform these compounds into molecular forms that vascular plants can use.¹ AMF also enhance the uptake of liquid water by vascular plants and protect soils and soil microbes from wind and water erosion.² AMF help seedlings to establish in grassland soils.³ AMF even operate as a rapid communications network to warn vascular plants of coming aphid attacks.⁴

Detoxifying Fungi
As impressive as these AMF contributions to vascular plants are, recent discoveries reveal that they contribute even more. Field studies by two ecologists showed that "synergistic interactions between plant roots, AMF and hydrocarbon-degrading microorganisms demonstrated high effectiveness in dissipation of organic pollutants in soil."⁵ In particular, the two ecologists determined that thanks to AMF, vascular plants can survive contamination from oil spills and polycyclic aromatic hydrocarbons (byproducts of fossil fuel, wood, and charcoal burning).

Another team of four ecologists at Dartmouth College performed experiments that established that the AMF Metarhizium robertsii breaks down highly toxic mercury and mercury compounds into less toxic mercury compounds.⁶ The four ecologists determined that two enzymes produced by M. robertsii were responsible for detoxifying the deadly mercury and mercury compounds. They then genetically engineered M. robertsii to produce higher amounts of the two enzymes. Next, they planted three fields of corn in soil that was heavily contaminated with toxic mercury and mercury compounds: one where the corn was not in a symbiotic relationship with M. robertsii, a second where the corn was in a symbiotic relationship with genetically unmodified M. robertsii, and a third where the corn was in a symbiotic relationship with the genetically engineered M. robertsii.

In the first field, the corn was severely stunted to the point where there would be no crop. In the second field, the corn grew well but was slightly retarded compared to corn grown in uncontaminated soil. In the third field, the researchers could not detect any difference between the corn plants in that field and the corn planted in uncontaminated soil. The Dartmouth team did another set of experiments in which they demonstrated that genetically modified M. robertsii—within just two days—could clear high levels of mercury and toxic mercury compounds from both freshwater and saltwater even at levels more than 1,000 times higher than the maximum limit recommended by the Environmental Protection Agency.

In their concluding remarks, the ecologists noted that the release of mercury and toxic mercury compounds from industrial activity poses "a fast-increasing threat to agriculture and ecosystems."⁷ Another threat arises from the increased melting of permafrost resulting from the warming of Earth's high-latitude regions. That melting has accelerated the release of mercury and toxic mercury compounds into soils, rivers, lakes, and oceans.

The research team observed several additional advantages in the use of Metarhizium species to treat mercury-polluted soils. Metarhizium species are among the most abundant soil fungi.⁸ They can easily be applied to seeds before planting.⁹ They develop symbiotic relationships with vascular plants that include trees, grasses, crops, and vegetables.¹⁰ They also protect plants from insect pests and can be produced industrially at high volume and low cost.¹¹

Design Implications
The latest research on AMF reveals that they are designed to benefit vascular plants under natural ecological conditions and under conditions harmfully altered by human industrial activity. The diversity of designs in AMF that have no direct benefit for AMF but have enormous benefits for vascular plants growing in natural settings strongly argues for supernatural, super-intelligent intent. Beyond that, the fact that AMF possess complex designs to offset human abuse of natural ecosystems argues for a supernatural, super-intelligent Being who knew that humans would rebel against him. This Being, the God of the Bible, anticipated the precise ways in which humans would fail in their mandate to manage Earth's resources for the benefit of all life (Genesis 1:28–30). Thus, with foreknowledge and planning, he designed specific species of life to lessen and repair the damage humans would bring upon Earth's ecosystems.

Endnotes

1. Lin Zhang et al., "Arbuscular Mycorrhizal Fungi Stimulate Organic Phosphate Mobilization Associated with Changing Bacterial Community Structure under Field Conditions," Environmental Microbiology 20, no. 7 (July 2018): 2639–2651, doi:10.1111/1462-2920.14289; James W. Allen and Yair Shachar-Hill, "Sulfur Transfer through an Arbuscular Mycorrhiza," Plant Physiology 149, no. 1 (January 2009): 549–560, doi:10.1104/pp.108.129866; H. Jin et al., "The Uptake, Metabolism, Transport and Transfer of Nitrogen in an Arbuscular Mycorrhizal Symbiosis," New Phytologist 168, no. 3 (December 2005): 687–696, doi:10.1111/j.1469-8137.2005.01536.x.
2. Yanyan Han et al., "Effect of Arbuscular Mycorrhizal Fungi and Phosphorus on Drought-Induced Oxidative Stress and 14-3-3 Proteins Gene Expression of Populus cathayana," Frontiers in Microbiology 11, no. 13 (August 2022): id. 934964, doi:10.3389/fmicb.2022.934964; Zhang et al., "Arbuscular Mycorrhizal Fungi Stimulate," 2639–2651.
3. Marcel G. A. Van Der Heijden, "Arbuscular Mycorrhizal Fungi as Support for Seedling Establishment in Grassland," Ecology Letters 7, no. 4 (April 2004): 293–303, doi:10.1111/j.1461-0248.2004.00577.x; Minxia Liang et al., "Soil Fungal Networks Moderate Density-Dependent Survival and Growth of Seedlings," New Phytologist 230, no. 5 (June 2021): 2061–2071, doi:10.1111/nph.17237.
4. Zdenka Babikova et al., "Underground Signals Carried through Common Mycelial Networks Warn Neighboring Plants of Aphid Attack," Ecology Letters 16, no. 7 (July 2013): 835–843, doi:10.1111/ele.12115; Zdenka Babikova et al., "How Rapid Is Aphid-Induced Signal Transfer between Plants Via Common Mycelial Networks?" Communicative & Integrative Biology 6, no. 6 (November 1, 2013): id. e25904, doi:10.4161/cib.25904.
5. Monika Rajtor and Zofia Piotrowska-Seget, "Prospects for Arbuscular Mycorrhizal Fungi (AMF) to Assist in Phytoremediation of Soil Hydrocarbon Contaminants," Chemosphere 162 (November 2016): 105, doi:10.1016/j.chemosphere.2016.07.071.
6. Congcong Wu et al., "Bioremediation of Mercury-Polluted Soil and Water by the Plant Symbiotic Fungus Metarhizium robertsii," Proceedings of the National Academy of Sciences USA 119, no. 47 (November 14, 2022): id. e2214513119, doi:10.1073/pnas.2214513119..
7. Wu et al., "Bioremediation of Mercury-Polluted Soil," p. 6.
8. Raymond J. St. Leger and Jonathan B. Wang, "Metarhizium: Jack of All Trades, Master of Many," Open Biology 10, no. 12 (December 9, 2020): id. 200307, doi:10.1098/rsob.200307.
9. Xinggang Liao et al., "The Plant Beneficial Effects of Metarhizium Species Correlate with Their Association with Roots," Applied Microbiology and Biotechnology 98 (August 2014): 7089–7096, doi:10.1007/s00253-014-5788-2.
10. Imtiaz Ahmad et al., "Endophytic Metarhizium robertsii Promotes Maize Growth, Suppresses Insect Growth, and Alters Plant Defense Gene Expression," Biological Control 144 (May 2020): id. 104167, doi:10.1016/j.biocontrol.2019.104167.
11. H. Zhao, B. Lovett, and W. Fang, "Genetically Engineering Entomopathogenic Fungi," Advances in Genetics 94 (2016): 137–163, doi:10.1016/bs.adgen.2015.11.001; Raymond J. St. Leger, "From the Lab to the Last Mile: Deploying Transgenic Approaches against Mosquitoes," Frontiers in Tropical Diseases (December 22, 2021), doi:10.3389/fitd.2021.804066; Ahmad et al., "Endophytic Metarhizium robertsii Promotes."