Evidence of Mycorrhizae and Beneficial Bacteria in Promoting Cannabis Health and Yield

Hemp harvesting on the banks of Rhine river, 1860s

Cannabis (Cannabis sativa) has a documented history of cultivation that extends over thousands of years, with evidence dating back to at least the Neolithic era. Initially domesticated in Eastern Asia, cannabis became a significant part of human culture due to its adaptability and multitude of uses, including fiber production, medicinal applications, and food sources.

 The spread of cannabis across continents was influenced by human migrations and trade, integrating deeply with agricultural practices across Europe, Asia, and Africa. Throughout its long history, cannabis has co-evolved with the natural environment, forming mutually beneficial relationships with organisms such as mycorrhizal fungi and Plant Growth-Promoting Rhizobacteria (PGPR). 

Hemp plant illustration from a botanical atlas, 19th century Europe

Co-Evolution with Mycorrhizal Fungi 

One of the most remarkable aspects of cannabis’s evolutionary history is its symbiosis with mycorrhizal fungi. These fungi are symbiotic with most terrestrial plants, forming associations that extend root networks and enhance the plant's ability to access water and essential nutrients in exchange for carbohydrates produced by plants.

 Rhizophagus irregularis (Glomus intraradices) a species of arbuscular mycorrhizal fungi (AMF), is known to form extensive hyphal networks that connect with cannabis roots, facilitating increased absorption of phosphorus and other minerals that are often limited in soil.

Pseudomonas spp. in the rhizosphere and its' influence for cannabis plant growth

The process by which AMF enhances nutrient uptake involves the fungi penetrating the root cells and forming arbuscules—structures that facilitate the exchange of nutrients between the plant and the fungus. The plant supplies the fungi with carbon derived from photosynthesis, while the fungi provide the plant with improved access to phosphorus, nitrogen, and micronutrients. This relationship is particularly valuable in cannabis cultivation, where phosphorus is essential for robust growth and flowering. Studies have shown that cannabis plants with AMF associations exhibit better root mass, increased growth rates, and enhanced resilience to environmental stressors​.

The Role of Trichoderma and Beneficial Bacteria 

Trichoderma harzianum in cannabis rhizosphere

In addition to mycorrhizal fungi, Trichoderma harzianum plays an integral role in promoting cannabis health. This beneficial fungus colonises the rhizosphere, producing growth hormones such as indole-3-acetic acid (IAA), which stimulate root branching and elongation. The result is a more extensive root system capable of greater nutrient and water absorption. Furthermore, Trichoderma acts as a natural biocontrol agent by releasing lytic enzymes and secondary metabolites that deter soil-borne pathogens, thereby reducing disease incidence and promoting overall plant vitality.

Benefits of a healthy and diverse rhizosphere

Beneficial bacteria, particularly strains of Bacillus and Lactobacillus, add another layer of support to cannabis cultivation:

• Nutrient Solubilization: 

Bacillus subtilis and related strains enhance the availability of phosphorus and potassium in the soil, making these nutrients more accessible to the plant. This solubilization process is essential for cannabis, which requires ample nutrients for vigorous growth and development.

• Pathogen Suppression: 

Bacillus spp. produce bioactive lipopeptides and enzymes that protect the plant from fungal pathogens, reinforcing the plant’s ability to withstand biotic stress.

• Soil Fertility Enhancement:

 Lactobacillus spp., such as L. casei and L. plantarum, contribute to the breakdown of organic matter and nutrient cycling, enriching soil fertility and ensuring that cannabis plants have a consistent supply of essential nutrients throughout their growth cycle​.

Historical and Ecological Significance 

Cannabis’s extensive use throughout history also intersected with traditional agricultural practices that leveraged the plant’s resilience and diverse applications. For example, hemp retting, a process used to extract fibers from cannabis stems by submerging them in water, has been practiced for centuries. Historical sediment analyses in places like the French Massif Central have revealed the presence of cannabinol (CBN), a phytocannabinoid metabolite, in ancient sediments. This finding underscores the deep connection between human activity and cannabis cultivation over centuries​.

Retting, although beneficial for producing high-quality fibers, has historically posed environmental challenges by affecting water quality. This highlights the importance of modern, sustainable practices that maintain productivity while protecting natural resources. The use of microbial inoculants such as AMF, Trichoderma, and beneficial bacteria supports sustainable agricultural systems by enhancing soil health, reducing dependency on chemical fertilisers, and improving carbon capture.

Modern Applications: The Role of Microbial Products 

The co-evolution of cannabis with beneficial microbes provides a strong foundation for modern microbial technologies aimed at sustainable cultivation. Our Super Microbes brand, with products like RootX and BoostX incorporates these naturally occurring relationships backed by science and research:

• RootX: 

Integrates Glomus intraradices, Trichoderma harzianum, and 13 species of Bacillus to extend root systems, optimize nutrient absorption, and offer natural protection against pathogens. This synergy helps cannabis plants achieve vigorous growth and enhanced yield.

• BoostX:

 Focuses on enriching the microbial environment with multiple strains of Bacillus, Lactobacillus, Rhodopseudomonas palustris, and Saccharomyces cerevisiae. These components increase nutrient bioavailability, promote robust flowering and bud formation, and contribute to sustained soil health.

Environmental Benefits and Carbon Sequestration

The integration of mycorrhizal fungi and beneficial bacteria into cannabis cultivation also plays a significant role in climate resilience. Mycorrhizal networks contribute to soil carbon storage by stabilizing organic matter and forming stable carbon pools as their structures decompose. The allocation of 5-20% of carbon captured by plants to support mycorrhizal fungi showcases their vital role in the carbon cycle. Estimates indicate that mycorrhizal fungi contribute to sequestering approximately 13 Gt of CO2e annually, a significant portion of the global carbon output​..

Conclusion 

The symbiosis between cannabis and organisms like mycorrhizal fungi and beneficial bacteria is just a small example of nature's complexity and adaptability. Understanding and harnessing these relationships not only improve plant health and yield but also foster sustainable agricultural practices that contribute to soil health and carbon capture. The continued study and application of these beneficial interactions can support ecological restoration efforts and bolster climate-positive outcomes, paving the way for a more resilient and sustainable agricultural future.

References:

McPartland, J. M., & Guy, G. W. (2004). The evolution of cannabis and co-evolution with the human species.

Clarke, R. C., & Merlin, M. D. (2013). Cannabis: Evolution and Ethnobotany. University of California Press.

Lavrieux, M., et al. (2013). Sedimentary cannabinol tracks the history of hemp retting in Lake Aydat, France. Geology, 41(7), 1-4.

Mercuri, A. M., et al. (2002). The identification and analysis of Cannabis pollen in archaeological and natural environments. Journal of Archaeological Science.

Rull, V., et al. (2022). Historical biogeography of Cannabis in the Iberian Peninsula: Palynological evidence. Vegetation History and Archaeobotany.

Duvall, C. S. (2014). The African Roots of Marijuana. Duke University Press.

Small, E. (2015). Cannabis: A Complete Guide. CRC Press.

Effect of Colonization of Trichoderma harzianum on Growth Development and

CBD Content of Hemp (Cannabis sativa L.)

Article in Microorganisms · March 2021

DOI: 10.3390/microorganisms9030518

 Trichoderma and its role in biological control of plant fungal and nematode disease 

Xin Yao 1†, Hailin Guo 2†, Kaixuan Zhang 3†, Mengyu Zhao 1, Jingjun Ruan 1* and Jie Chen 4* 

1 College of Agronomy, Guizhou University, Guiyang, China, 2 Science and Technology Innovation Development Center of Bijie City, Bijie, China, 3 Institute of Crop Science, Chinese Academy of Agriculture Science, Beijing, China, 4 School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China