センサーでピーナッツの真菌病を早期検出（Protecting the peanut: Sensors help fend off fungus）

2026-08-31 バージニア工科大学（Virginia Tech）

A new sensor developed by Virginia Tech researchers can detect Sclerotinia blight in peanut plant sap. Photo by Suzanne Pruitt for Virginia Tech.

＜関連情報＞

• https://news.vt.edu/articles/2026/08/protecting-the-peanut–sensors-help-fend-off-fungus.html
• https://pubs.acs.org/aastgj/article/6/8/1485/5227112/Oxalate-Linked-Electrochemistry-Enables-Early
• https://pubs.acs.org/ascefj/article/11/7/6128/5172544/Additively-Manufactured-in-planta-Integrated

シュウ酸塩結合電気化学により、3Dプリントされたナノ構造Ptセンサーを用いたピーナッツ作物の菌核病の早期検出が可能になる Oxalate-Linked Electrochemistry Enables Early Detection of Sclerotinia Blight in Peanut Crops Using 3D-Printed Nanostructured Pt Sensors

Frank Efe Erukainure ;Blake N. Johnson;David B. Langston;Abhilash K. Chandel
ACS Agricultural Science & Technology  Published:July 22, 2026
DOI:https://doi.org/10.1021/acsagscitech.6c00185

Abstract

Sclerotinia minor (causing Sclerotinia blight) is a devastating pathogen in peanut production, with severe outbreaks causing up to 50% yield loss due to rapid oxalic acid (OA) accumulation. Early diagnosis is challenging because canopy-level symptoms typically emerge only after infection is well established, while early cues are subtle, stem-localized, and nonspecific; in contrast, molecular assays are time- and resource-intensive. Despite established mechanistic links between oxalate accumulation and disease progression, so far, there are no sensors developed or tested for detecting Sclerotinia blight in peanut plants. This paper reports a low-cost, lithography-free, and label-free electrochemical sensor for metabolite-targeted, presymptomatic monitoring of S. minor in peanut plants based on clear mechanistic links between oxalate accumulation and disease progression. The sensor platform comprises 3D-printed resin substrates with platinum (Pt) electrodes and a nanostructured reduced graphene oxide (rGO)−chitosan interface functionalized with an oxaloacetic acid (OAA) interfacial layer. Using ferri/ferrocyanide as a redox probe, the sensor exhibited a linear calibration to oxalate (prepared from OA) from 0.05 µM to 1 mM (R² = 0.99), with a sensitivity of 6.37 µA/decade, limit of detection of 17.6 nM, and excellent coefficient of variation of 0.93−3.32% across standards (n = 4). In real plant trials, stem sap from S. minor–inoculated peanut plants produced significantly elevated voltammetric responses relative to healthy and Nothopassalora personata controls as early as five days post-inoculation (dpi), enabling longitudinal monitoring through 20 dpi (p < 0.001). Oxalate-equivalent mapping showed progressive increases in infected plants, reaching mM levels by 20 dpi, while the validated sensor readings agreed with those of a commercial assay during oxalate-linked S. minor detection in peanut plants. To our knowledge, this is the first demonstration of a 3D-printed, Pt-based electrochemical platform validated with peanut plants for early, metabolite-linked detection of Sclerotinia blight, providing a practical foundation for point-of-need surveillance and precision disease management in peanut production systems.

植物体内で 積層造形されたマイクロニードル・マイクロ流体統合センシング：農作物におけるグルコースおよび水分ストレスの非破壊電気化学的追跡 Additively Manufactured in planta Integrated Microneedle–Microfluidic Sensing: Nondestructive Electrochemical Tracking of Glucose and Water Stress in Agricultural Crop Plants

Frank Efe Erukainure ;Blake N. Johnson;David B. Langston;Abhilash K. Chandel
ACS Sensors  Published:July 02, 2026
DOI:https://doi.org/10.1021/acssensors.6c01122

Abstract

Timely quantification of crop stress physiology remains challenging because conventional assays are destructive, labor-intensive, and poorly suited for continuous monitoring and field deployment. Here, we report a microneedle-enabled electrochemical biosensing platform with smartphone-based data collection for the in planta monitoring of plant stress that integrates three design innovations in a single architecture: (i) a fully integrated hollow microneedle–microfluidic measurement pathway for sap access, (ii) physical isolation of the metal electrodes from direct tissue contact to reduce insertion-zone abrasion of the sensing interface, improving biocompatibility and potentially lowering fouling pathways, and (iii) lithography-free fabrication of a modular transducer on an additively manufactured substrate. The platform comprises a three-electrode gold (Au) transducer modified with a nanostructured reduced graphene oxide (rGO)–chitosan layer. The biosensing platform enabled dual sensing channels via functionalized glucose oxidase (GO_x) and horseradish peroxidase (HRP) for the detection of glucose and water stress-associated hydrogen peroxide (H₂O₂), respectively. The glucose channel showed a strong linear calibration over the tested range, with Pearson’s r = 0.99, R² = 0.98, sensitivity of 62.34 μA/mM, and a limit of detection (LOD) of 102.50 μM (∼1.85 mg/dL), while the H₂O₂ channel exhibited Pearson’s r = 0.99, R² = 0.99, sensitivity of 3.65 μA/decade, and an LOD of 3.22 μM. Repeatability across measured standards remained high for both channels, with mean coefficients of variation of 1.31% for glucose and 1.16% for H₂O₂. Ex vivo measurements in plant sap, including standard-addition experiments and comparison with commercial benchmark assays, provided validation of analyte concentration determination in plant-derived samples. In planta measurements on maize plants (Zea mays L.) grown under graded watering treatments revealed statistically significant treatment-dependent glucose and H₂O₂ signatures over time (p < 0.05), consistent with carbon-status and oxidative-stress responses to water deficit, respectively. This integrated, manufacturable platform provides a practical route toward real-time, data-driven crop management using minimally invasive electrochemical readouts.