In Situ Plant Sensors: Toward Real-Time, High-Resolution Monitoring.

The field of plant sensing technologies is undergoing a transformative shift, driven by innovations in both flexible wearable devices and genetically encoded sensors (GESs). From this standpoint, we emphasize their potential in real-time, in situ monitoring of plant physiology and stress responses. Wearable sensors enable continuous detection of plant growth, microclimate, water transport, surface potential, and immune responses, offering unprecedented insight at the tissue level. In parallel, GESs provide high-resolution, intracellular visualization of key signaling molecules such as calcium, reactive oxygen species, and plant hormones, as well as dynamic changes in pH. While these technologies represent significant advancements over traditional methods, practical challenges remain. Issues of adaptability, sensing stability, spatial resolution, limited parameter coverage, and integration across sensing modalities require further investigation. We envision a future in which interdisciplinary approaches, including material science, engineering, synthetic biology, and data analytics, enable the development of robust, scalable, and multimodal plant sensing systems. These next-generation tools could revolutionize high-throughput phenotyping, precision agriculture, and fundamental plant biology, ultimately contributing to more sustainable and resilient agricultural systems.