Investigating the Effects of Benzoxazinoids on Arbuscular Mycorrhizal Fungi Colonization in Maize Crops

The rhizosphere microbiome is an important driver of agricultural yields as it promotes mutualistic relationships between plants and the microorganisms that associate in the soil. For example, the symbiotic interactions between maize roots and arbuscular mycorrhizal fungi (AMF) are known to drive positive plant-soil feedbacks, which improves overall plant performance and defense against herbivores for plants growing in the next generation. However, these plant-associated microbiomes are influenced by secondary metabolites exuded by plant roots. Benzoxazinoids (BXs), for example, are one class of defensive secondary metabolites in maize crops, which may inhibit the colonization of pathogenic fungi. The BX breakdown products, BOA and MBOA, are compounds that influence plant-soil feedback due to their anti-fungal properties. We hypothesized that BXs may inhibit colonization, which may lead to negative plant-soil feedback. We predicted that the BOA and MBOA would inhibit spore germination and presymbiotic hyphal elongation. From this research, we hope to address plant-soil interactions and agricultural challenges at the metabolic level of plants by better understanding how BX activity influences AMF colonization in maize crops. Through the manipulation of plant metabolism and interactions with AFM, opportunities for more effective pest and weed control practices will be available.