Hot or not: Quantifying isothiocyanates in plants, soil, and other media

Authors: HOGABOAM, OCTAVIA - Oregon State University; Manning, Viola; Reardon, Catherine; Trippe, Kristin

Submitted to: Biosensors and Bioelectronics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/4/2025
Publication Date: 3/15/2025
Citation: Hogaboam, O., Manning, V., Reardon, C.L., Trippe, K.M. 2025. Hot or not: Quantifying isothiocyanates in plants, soil, and other media. Biosensors and Bioelectronics. 24. Article 100599. https://doi.org/10.1016/j.biosx.2025.100599.
DOI: https://doi.org/10.1016/j.biosx.2025.100599

Interpretive Summary: Isothiocyanates (ITCs), volatile and toxic compounds produced by plants in the mustard family, provide flavor and aroma to plants like broccoli and radish. These compounds also help plants defend themselves against pests and pathogens. While ITCs have agricultural, industrial, and health applications, measuring and detecting ITCs is complex and expensive. In this study, we designed a bacterium that glows in the presence of ITCs. This biosensor, termed SaxAPIL, can detect ITCs in a dose-dependent manner in a broad spectrum of specimens including extracts of plants and soil. Our results demonstrate the potential of SaxAPIL as a rapid, inexpensive tool for detecting ITCs in agricultural, industrial, and health-related contexts.

Technical Abstract: Isothiocyanates (ITCs), volatile and toxic compounds produced by plants in the Brassicales order, serve as natural defense mechanisms against pests and pathogens. In agricultural settings, natural and synthetic ITCs are used to biofumigate soils prior to planting, however, biofumigation of soils requires monitoring to ensure that residual ITCs do not inhibit germination or plant growth. Current methodologies that measure ITCs are labor intensive and require expensive, bulky instrumentation. Therefore, there is a critical need for rapid, reliable, and inexpensive methods that detect ITC in a variety of plant and soil matrices. In this study, we utilized an ITC-responsive promoter to drive expression of a bioluminescent operon in Pseudomonas fluorescens SBW25. This biosensor, referred to as SaxAPIL, specifically reacts to ITCs in a dose-dependent manner. Our results indicate that SaxAPIL can be used in high throughput microplate-based assays to detect ITCs at various concentrations in solutions, plant-derived extracts, seed meal extracts, and in amended soils. While our results clearly demonstrate that SaxAPIL is a robust biosensor for the detection and quantification of aliphatic ITCs in plants and soil, the methodology presented here can be adapted to quantify ITCs in other media to provide more efficient and less expensive methods to measure ITCs in industrial, health, and life science applications.