Smartphone LAMP Plant Pathogen Test

ISEF Category: Biochemistry

Subcategory: Analytical Biochemistry  ·  Difficulty: Advanced  ·  Setup: School Lab  ·  Time: Full Year

The Hook

A sick tomato plant can look fine long before you notice the pathogen. That means a tiny DNA test can give you a big head start. With a sous-vide cooker and your phone, you can turn a leaf sample into a color signal. This project links kitchen tools to real plant disease detection.

What Is It?

Loop-mediated isothermal amplification, or LAMP, is a DNA test that copies one target sequence at one steady temperature. Think of it like a copier that keeps running at the same speed, while PCR is more like a machine that keeps changing gears. That steady setup makes LAMP a good fit for a simple water bath.

Colorimetric LAMP adds a dye that changes color when the reaction works. If the pathogen DNA is in your plant sample, the tube shifts in a way your phone can measure from a photo. Your job is to turn that color change into a clean test for garden samples, not just a yes-or-no guess.

Why This Is a Good Topic

This topic works well because you can change one variable at a time, like the plant species, the extraction method, or the color-reading workflow. It connects directly to crop health and backyard gardening, where fast disease checks matter. You can learn primer design, contamination control, calibration, and data analysis without needing a full research lab.

Research Questions

• How does the plant DNA extraction method affect the color signal from infected leaf samples?
• What is the effect of sample dilution on the lowest pathogen level your assay can detect?
• Does the assay separate the target pathogen from closely related non-target species?
• To what extent does temperature drift in the sous-vide bath change the time to a positive color shift?
• Which phone-based color metric best distinguishes true positives from negative controls?
• How does leaf species background chemistry change false-positive rates in garden samples?

Basic Materials

• Smartphone with a fixed stand or tripod.
• Sous-vide cooker or precision water bath.
• Colorimetric LAMP master mix and target-specific primer set.
• Plant DNA extraction kit or school-lab extraction reagents.
• Sterile microcentrifuge tubes and filtered pipette tips.
• Micropipettes with compatible tips.
• White background or light box for photos.
• Disposable gloves, lab coat, and DNA-free bench supplies.

Advanced Materials

• Benchtop centrifuge.
• PCR hood or clean bench.
• Gel electrophoresis system.
• Fluorometer or qPCR machine for validation.
• DNA quantification instrument.
• Positive control DNA and close-relative control templates.

Software & Tools

• ImageJ: Measures color intensity from standardized tube photos and compares samples.
• Python: Fits calibration curves, calculates signal ratios, and runs basic statistics.
• NCBI Primer-BLAST: Checks whether your primers match the target and avoid close relatives.
• Google Sheets: Organizes replicate data and makes quick graphs for early analysis.

Experiment Steps

1. Define the pathogen, host plant, and DNA marker you want to detect.
2. Check primer specificity against close relatives and common garden contaminants.
3. Set a temperature-control plan for the sous-vide bath and confirm that the bath stays steady during a full run.
4. Design a photo setup that fixes lighting, distance, and background before you compare tube color.
5. Plan positive, negative, and no-template controls, plus a way to test real plant samples against known standards.
6. Choose the analysis rule that turns color into a call, then decide how you will report sensitivity, specificity, and repeatability.

Common Pitfalls

• Using the same pipette tip after amplified samples, which spreads DNA and creates false positives.
• Letting the water bath drift outside the target range, which changes reaction speed and weakens the color call.
• Photographing tubes under different light or phone settings, which breaks color comparison across days.
• Testing only one infected plant and one healthy plant, which hides how the assay behaves on real garden material.
• Skipping cleanup for leaf pigments and sap, which can block the reaction or distort the dye color.

What Makes This Competitive

A stronger entry would do more than prove the assay works. It would measure how far the test can push down to low DNA levels, compare several close species, and use blinded samples. If you add image-based quantification and solid statistics, you can show where your method beats a visual readout and where it still fails.

Project Variations

• Test different garden crops, such as tomato, pepper, or basil, to compare how host tissue changes assay performance.
• Swap the phone-based analysis for ImageJ or Python and compare which readout gives the cleanest separation.
• Benchmark the LAMP assay against a DNA gel or a commercial test kit to study sensitivity and false positives.

Learn More

• PubMed: Search review articles on LAMP plant pathogen detection and colorimetric nucleic acid tests.
• NCBI Primer-BLAST: Check primer specificity against related plant and pathogen sequences on the NCBI site.
• NCBI GenBank: Download target and off-target DNA sequences for marker comparison on the NCBI site.
• USDA APHIS Plant Health pages: Find disease fact sheets, host ranges, and plant quarantine background on the USDA site.
• NCBI Bookshelf: Read free chapters on nucleic acid amplification and molecular diagnostics.