In Vivo Monitoring of Energy Metabolism with Genetically Encoded Fluorescent Biosensors

All organisms fuel and build themselves through their energy metabolism. While classic biochemistry conceptualizes the fluxes of energy and matter, our understanding of how energy metabolism works in vivo contains major gaps. One reason is that energy metabolism spans multiple scales, from enzymes to organs, and shifts dynamically at environmental and developmental transitions, resulting in a degree of complexity that is presently impossible to capture. Genetically encoded fluorescent biosensors have started to bridge several critical gaps by enabling live monitoring of metabolites across scales. Recently, several paradigms of energy metabolism have started to shift, driven by the expansion of biosensing tools. This review explores advancements in our understanding of plant energy metabolism driven by fluorescent protein biosensing, highlights emerging concepts and open questions, and discusses how available tools, and much-needed future innovations, can unlock the potential of biosensing toward understanding in vivo plant energy metabolism and its effective modification.