Plant’s Talk: A Study of the Effects of Mycorrhizal Communication between Agricultural Crops

Project Overview: The goal of this project was to further explore, measure and demonstrate the ecological role of mycorrhizal fungi in plant communication, specifically for possible beneficial agricultural purposes. Improving upon agricultural yield and sustainability generally includes: Increasing Crop Diversity (Reduction of Monoculture Practices) Crop Rotation Genetic Modification Pesticide Alternatives: Trap Crops, Biological Pesticides etc. Newer Considerations…..Plant Communication: Fungal Networks? Often Overlooked and excluded to plowing and general soil depletion

Quick Working Definition Mycorrhizae: term regarding the symbiotic relationship formed between the root system of a host plant and fungi. Plant receives increased nutrient and water uptake Fungi receives increased carbohydrates Fungi allows for signaling between plants (“talking”) Symbiotic Relationship: when two organisms perform mutually beneficial tasks

Hypothesis For both the soybean and corn crops, those both fully inoculated and allowed communication via unblocked fungal networks will show the greatest relative pest resistance and photosynthetic rates.

Methods Split trials of corn and soybean into inoculated and sterile Test baseline photosynthetic rates Test growth rates and physiological traits (RGR) Expose them to pests over time with further divisions Sterile, Barrier -- (no latent benefit no comm.) Sterile, No Barrier -- (no latent benefit, possible root comm.) Inoculated, Barrier +- (latent benefit, no comm. ) Inoculated, No Barrier ++ (latent benefit, comm. ) Retest photosynthetic rates and related curves on Licor and weight Once in growth chamber again in field setting: Local Princeton Farm

Licor Measurements: Photosynthesis Limiting Factors Rubisco-catalyzed carboxylation Rate of RuBP regeneration via electron transport (J) Rate of RuBP regeneration via triose phosphate utilization (TPU) Used Python to form dataframes from Licor data, perform statistical analysis Graphed data from Licor taken from plants under different experimental conditions for comparison Used Michaelis-Menten function and additional mathematical relationships to predict TPU compensation point and Vcmax

Results Growth Chamber Princeton Farms Preliminary data showed a pattern similar to our hypothesis Princeton Farms Results still inconclusive due to weather and pest related sample size reduction. Data still currently being sorted through and analyzed

Discussion This study and others show interesting results and fit into the overarching ecological goal of reducing agricultural impact on the environment and improving upon inefficient practices The study of mycorrhizal fungi as a tool for pesticide and fertilizer reduction specifically is still relatively new and promising Expansion upon this experiment especially in an authentic agricultural setting is especially needed

Acknowledgements Thank you to both Paul Gathier, Kelly Caylor for being incredibly helpful and encouraging advisors Thanks to Olivia Trase for inviting us to work with her on such an engaging new topic and Ioannis Vandris for helping out as a fellow intern Thanks to those involved with Princeton’s farmland for allowing us to work among them