Potential of Spatially Offset Raman Spectroscopy for Detection of Zebra Chip and Potato Virus Y Diseases of Potatoes (Solanum tuberosum)

Abstract

Potato (Solanum tuberosum L.) is a staple food crop and part of an industry valued at an estimated $3.77 billion in the United States. Many varieties of potato are susceptible to zebra chip disease (ZC), a psyllid-vectored bacterial infection that renders the tubers unmarketable due to unappealing discoloration and taste. Similarly, potato virus Y (PVY) is a major pathogen of potatoes and other solanaceous crops that causes devastating damage to both foliage and tubers. These diseases are typically detected by enzyme-linked immunosorbent assay or polymerase chain reaction. ZC can also be diagnosed by a visual inspection of cut open tubers followed by frying to reveal the characteristic striping symptoms. However, these methods are invasive and destructive, as well as reagent, time, and labor consuming. Thus, quick and sample-general alternative methods for disease detection are highly desirable. In this proof-of-principle work, we demonstrate that spatially offset Raman spectroscopy (SORS) shows great potential for rapid and reagent-free detection of ZC or PVY diseases. Such detection is based on Raman identification of chemical changes in tubers associated with ZC or PVY. Chemometric analysis of spectra from intact potato tubers demonstrated over 90% accuracy of ZC detection. With data from cut open tubers, the prediction accuracy for ZC increased to over 90% for the prediction of PVY disease. We also show that potatoes from plants with either ZC or PVY diseases can be distinguished from each other and healthy tubers with approximately 95% accuracy. These results suggest that SORS has potential for noninvasive diagnostics of potato diseases.

Raman spectroscopy‐based diagnostics of water deficit and salinity stresses in two accessions of peanut

“…Spectra collected from leaves of peanuts exhibited vibrational bands assigned to pectin (747 cm À1 ), cellulose (480, 520, 917, 1,048, and 1,080 cm À1 ), xylan (1,185 cm À1 ), carotenoids (1,000, 1,155, and 1,525cm À1 ), phenylpropanoids (1,605 cm À1 ), protein (1,654 cm À1 ), and aliphatic vibrations (1,218, 1,285, 1,327, 1,339, 1,387, and 1,442 cm À1 ) (Figure 1 and Table 1). These assignments were made based on the previous studies reported by our and other research groups (Altangerel et al, 2017;Farber et al, 2021;Farber & Kurouski, 2018;Farber, Sanchez, Rizevsky, et al, 2020;Gupta et al, 2020;Mandrile et al, 2019;Payne & Kurouski, 2021;Sanchez, Ermolenkov, Tang, et al, 2020;Sanchez, Pant, Xing, et al, 2019). We found that spectra collected from stressed (symptomatic, D5) TX225 plants exhibited lower intensities of vibrational bands that originated from pectin, cellulose, xylan, aliphatic vibrations, and carotenoids compared to those of control plants (Figure 1).…”

“…Partial least squares discriminant analysis (PLS-DA) was performed to differentiate between the experimental classes and identify spectral regions that best explained separation between the classes. Our own experimental results, as well as findings reported by other groups, show that PLS-DA performs equally well or better than other chemometric methods, such as linear discriminant analysis (LDA) or soft independent modeling by class analogy (SIMCA) (Farber et al, 2021;Lee et al, 2018;Sanchez, Pant, Irey, et al, 2019;Sanchez, Pant, Mandadi, & Kurouski, 2020;Shashilov & Lednev, 2010). Therefore, we have selected PLS-DA for statistical analysis of spectra collected in this study.…”

“…We previously demonstrated that such Raman-based phenotyping can be used not only for identification of different peanut accessions but also for digital breeding and selection of plants (Farber, Sanchez, Rizevsky, et al, 2020). We also demonstrated that in potatoes, the performance of models for identifying biotic stress (zebra chip disease, ZC) in tubers was dependent on the variety: a model calibrated with one variety of potatoes could not accurately identify ZC-associated changes in potatoes of another variety (Farber et al, 2021).…”

“…The hand-held nature of the spectrometer used in our previous studies suggests that spectroscopic analysis of plants can be performed directly in the field or a greenhouse Farber et al, 2021;Farber, Sanchez, Rizevsky, et al, 2020;Farber, Shires, et al, 2019;Sanchez, Ermolenkov, Biswas, et al, 2020;Sanchez, Ermolenkov, Tang, et al, 2020). Expanding upon these findings, we investigated the accuracy of the Raman-based approach in the detection of water deficit and salinity stresses in two peanut accessions: Tamrun OL11, a water deficit stress-susceptible line, and TxL100225-05-07, a tolerant line developed in Lubbock, TX (Baring et al, 2013).…”

Potato Zebra Chip: An Overview of the Disease, Control Strategies, and Prospects

“…Polymerase chain reaction (PCR) and/or quantitative PCR is the most widely used diagnostic approach for detecting CLso in both the host plants and the psyllids, and can be used to distinguish the different haplotypes (Hansen et al, 2008;Secor et al, 2009;Swisher et al, 2012;Ananthakrishnan et al, 2013;Contreras-Rendón et al, 2020). Other emerging technologies such as Raman Spectroscopy are also being explored to detect ZC disease, that allows for rapid, non-invasive and in-field diagnostics (Farber et al, 2021).…”