(299g) Decoding Early Stress Signaling Waves in Plants Using Multiplexed Nanosensors

Plants are heavily influenced by environmental stresses that can have a significant impact on their growth and productivity. To cope with these stresses, plants activate a complex signaling cascade that leads to stress resistance or adaptation. However, due to the lack of real-time sensing tools capable of simultaneous measurements of multiple signaling molecules, the temporal ordering and composition of stress signaling cascades and their specificity to stresses remain largely unknown. In this work, we developed and validated a novel carbon nanotube-based sensor for salicylic acid (SA) and paired it with a H₂O₂ nanosensor, as these species are two key early stress signaling molecules that interact with each other to mediate stress responses. The sensors were used to monitor stress-induced H₂O₂ and SA signals in Brassica rapa subsp. Chinensis (Pak choi) plants subjected to different stress treatments, including light stress, heat stress, pathogen stress, and mechanical wounding. The nanosensors reported distinct dynamics and temporal wave characteristics of SA and H₂O₂ generation in tandem for each type of stress stimuli. For all stresses, the H₂O₂ wave was observed within minutes of stress perception, followed by recovery within the first hour. For SA, however, production onset occurred at different time points within two hours of stress perception, and no SA was measured for mechanical wounding. With insights gained from sensor multiplexing, we constructed a mathematical model that describes a potential mechanism by which stress specificity is captured by the unique H₂O₂ waveform generated shortly after stress perception by the plant. Our results demonstrate that sensor multiplexing is promising for elucidating stress signaling mechanisms in plants, which is a key step toward the development of climate-smart crops and pre-symptomatic diagnoses of stresses in field settings.