Handheld Raman spectroscopy for the early detection of plant diseases: Abutilon mosaic virus infecting Abutilon sp.

Plant diseases have a direct impact on the productivity of crops, and therefore the early detection of diseases is crucial. Abutilon mosaic virus (AbMV) (family Geminiviridae; genus Begomovirus) is an important virus infecting ornamental crops throughout the world. Abutilon hybridum showing bright yellow mosaic symptoms were observed in gardens in Tumbaco, Ecuador. The infection was confirmed by Polymerase Chain Reaction (PCR) using degenerate begomovirus primers. The amplicon (∼500 bp) was sequenced, submitted to NCBI (KP877621) and showed 68.7–100% and 72.7–100% sequence identity with other begomoviruses at nucleotide and amino acid levels, respectively. In order to evaluate Raman spectroscopy as a diagnostic tool for AbMV infection, spectra of leaves from healthy and infected plants were recorded. Raman signals of carotenoids are the most important features and there is a significant decrease in the intensity of these bands when the plant is infected. The difference in the intensity of the bands, particularly the one at 1526 cm−1, is proposed as a basis for the early detection of viral infection in plants.