The roots of most plants form symbioses with arbuscular mycorrhizal fungi (AMF), and harnessing these symbioses could reduce irrigation and fertilizer inputs for more sustainable production of many crops, including biofuel sorghum. Regents’ Professor Nancy Johnson in the School of Earth & Sustainability was awarded $1.3 million to collaborate with researchers at the University of Georgia to study the beneficial associations between biofuel sorghum and AMF. Despite decades of efforts, successful use of AMF as biofertilizers has been elusive, largely because mycorrhizae are complex systems and their effects are context dependent. Environmental conditions, and especially soil fertility and water availability, influence the degree to which AMF can improve sorghum production. Also, different genetic lines of sorghum vary in mycorrhizal responsiveness, and complex communities of AMF and other soil microbes differ in their effects on the nutrient and water relations of their host plants. A better understanding of natural communities of AMF in soils and the mechanisms that influence mycorrhizal functioning in field conditions is necessary before effective methods can be developed to manage AMF to increase sustainable biofuel sorghum production. This five-year research collaboration will study the sorghum genes involved in forming beneficial symbioses with AMF and other root-associated microbes. A series of field and greenhouse experiments in Georgia and Arizona will examine the genetic and environmental factors that cause the variable performance of mycorrhizal symbioses in field conditions. In addition to traditional research methods, innovative new approaches will be developed for high-throughput measurements of AMF in plant roots using convolutional neural network software. Novel imaging tools will also be applied for visualization of the interactions between sorghum roots and AMF. These studies will help advance basic understanding of the genetic mechanisms by which plants control their associations with potentially beneficial root-associated microbes. This knowledge is prerequisite to understanding the context dependent behavior of AMF in biofuel sorghum so that they can be effectively managed to maximize mycorrhizal benefits.