Time is an often-neglected variable in biological research. Plants respond to biotic and abiotic stressors with a range of chemical signals, but as plants are non-equilibrium systems, single-point measurements often cannot provide sufficient temporal resolution to capture these time-dependent signals. In this article, we critically review the advances in continuous monitoring of chemical signals in living plants under stress. We discuss methods for sustained measurement of the most important chemical species, including ions, organic molecules, inorganic molecules and radicals. We examine analytical and modelling approaches currently used to identify and predict stress in plants. We also explore how the methods discussed can be used for applications beyond a research laboratory, in agricultural settings. Finally, we present the current challenges and future perspectives for the continuous monitoring of chemical signals in plants.
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F.G. thanks the Bill and Melinda Gates Foundation (Grand Challenges Explorations scheme under grant number OPP1212574) and the US Army (U.S. Army Foreign Technology (and Science) Assessment Support programme under grant number W911QY-20-R-0022) for their generous support. L.G.-M. acknowledges the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement no. 101025390. F.G., P.C. and A.S.P.C. thank EPSRC (EP/L016702/1) and BBSRC DTP (reference 2177734). T.B. acknowledges BBSRC (BB/T006102/1) for their support. F.G. and P.C. thank the Imperial College Centre for Processable Electronics (CPE). F.G. also acknowledges Agri Futures Lab.
The authors declare no competing interests.
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Not capable of causing disease.
- Bioimpedance spectroscopy
A non-invasive electrochemical spectroscopic technique for the measurement of electrical impedance of biological samples.
- Effector-triggered immunity
(ETI). A stronger immune response triggered upon detection of effector proteins released by the pathogen.
- Electrical impedance
The opposition to electrical flow.
- Electrodic technique
A technique measuring properties at the electrode–electrolyte interface.
- Genetic transformations
Insertion and incorporation of exogenous genetic material into a host organism.
Fungus-like filamentous microorganisms.
- PAMP-triggered immunity
(PTI). The primary plant immunity response, triggered when PAMPs are detected by recognition receptors in plants.
- Pathogen-associated molecular patterns
(PAMPs). Structural molecular components of pathogens that are recognized by receptors in plants, triggering an immune response.
Living tissue that transports soluble organic compounds (especially sugars) produced during photosynthesis around the plant.
- Protease inhibitors
Large variety of antiherbivore molecules (mostly proteins) that inhibit protease enzyme function to reduce herbivore digestion.
Pores on the epidermis of leaves that control exchange of CO2 and water vapour with the environment.
- Stomatal aperture
The width of the pore size of a stoma as controlled by the two guard cells.
- Synthetic-aperture radar
A remote imaging technique involving the transmission and reception of sequential electromagnetic waves by a device on a moving platform.
Capable of causing disease.
Vascular tissue that transports water and dissolved nutrients up from the roots to other organs.
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Coatsworth, P., Gonzalez-Macia, L., Collins, A.S.P. et al. Continuous monitoring of chemical signals in plants under stress. Nat Rev Chem 7, 7–25 (2023). https://doi.org/10.1038/s41570-022-00443-0