Rapid Detection and Quantification of Plant Innate Immunity Response Using Raman Spectroscopy

Abstract

We have developed a rapid Raman spectroscopy-based method for the detection and quantification of early innate immunity responses in Arabidopsis and Choy Sum plants. Arabidopsis plants challenged with flg22 and elf18 elicitors could be differentiated from mock-treated plants by their Raman spectral fingerprints. From the difference Raman spectrum and the value of p at each Raman shift, we derived the Elicitor Response Index (ERI) as a quantitative measure of the response whereby a higher ERI value indicates a more significant elicitor-induced immune response. Among various Raman spectral bands contributing toward the ERI value, the most significant changes were observed in those associated with carotenoids and proteins. To validate these results, we investigated several characterized Arabidopsis pattern-triggered immunity (PTI) mutants. Compared to wild type (WT), positive regulatory mutants had ERI values close to zero, whereas negative regulatory mutants at early time points had higher ERI values. Similar to elicitor treatments, we derived an analogous Infection Response Index (IRI) as a quantitative measure to detect the early PTI response in Arabidopsis and Choy Sum plants infected with bacterial pathogens. The Raman spectral bands contributing toward a high IRI value were largely identical to the ERI Raman spectral bands. Raman spectroscopy is a convenient tool for rapid screening for Arabidopsis PTI mutants and may be suitable for the noninvasive and early diagnosis of pathogen-infected crop plants.

Integrating biopolymer design with physical unclonable functions for anticounterfeiting and product traceability in agriculture

“…However, the field of portable Raman for agricultural applications is rapidly advancing, adding merits of miniaturization, lower costs, and shorter spectrum acquisition time (47)(48)(49). As an example, handheld Raman spectrometers were recently developed for nondestructive monitoring of plant stresses in the field (50)(51)(52). As for verification of the visual PUF tags, the pocket microscope used in this study currently costs less than 23 USD, is battery-powered, and weighs less than 230 g. With a resolution of 1920 × 1080 pixels, the pocket microscope can be conveniently connected to a smartphone via its built-in Wi-Fi function so that anyone with a smartphone will be able to scan the visual tags and save the captured tag images in their smartphone or on a cloud service within seconds.…”

Emerging Extraction and Diagnostic Tools for Detection of Plant Pathogens: Recent Trends, Challenges, and Future Scope

“…They demonstrated that Raman spectral fingerprints could be used to distinguish between infected and noninfected plants, by employing flg22 and elf18 elicitors. The difference between the p value at each Raman shift was used to derive the elicitor response index (ERI) to quantify the immune response . Charlermroj et al reported a method involving use of immunoassay technology to detect four plant pathogens, out of which three were viruses and one was a bacterium.…”