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0Application of fluorescence spectroscopy for early detection of fungal infection of winter wheat grains
T. Matveeva*, R. Sarimov, S. Gudkov
Prokhorov General Physics Institute of the Russian Academy of Sciences, Russia, 119991,
Moscow, Vavilova st., 38
Rapid, on-line and cheap monitoring of plant diseases on their early stages is an actual and important problem of food security and food safety. Different optical methods meet these requirements and they are already widely used in the agriculture sector [1,2]. Fluorescence-based techniques are broadly applied in the investigation of biological samples and in particular for the separation of infected crop samples [3].
This work focused on using fluorescence spectroscopy to characterize and compare healthy and fungal pathogen-infected wheat grains. The aim of the work is to determine the characteristic features, parameters, and wavelengths to distinguish between healthy and infected grains at an early stage of infection and different types of infection. The excitation-emission matrices of whole-wheat grains were measured using a Fluorescence Spectrometer Jasco FP-8300.
The samples included control healthy samples, both dry and wet, and manually infected grains with Fusarium graminearum and Alternaria alternata fungi. The five distinct spectral areas were identified by analyzing the location of the fluorescence peaks at each measurement. The area centered at ^em=328/^ex=278 nm (emission/excitation of an amino acid peak) showed a twofold increase in intensity for grains infected with A. alternata after one day, whereas samples with F. graminearum showed a tenfold increase in fluorescence after seven days of infection. Another area with the center ^em=480/^ex=400 nm is most interesting from the point of view of early diagnostics of pathogen development. A statistically significant increase of fluorescence maxima for samples with F. graminearum is observed on 1 day after infection, for A. alternata on day 2, and by day 7, the fluorescence of both groups decreases to the control level. Moreover, shifts in the emission peaks from 444 nm to 452 nm were recorded as early as 2-3 hours after infection. Since the area centered on ^em=480/^ex=400 nm showed the greatest differences in the spectra of infected and uninfected samples, possible fluorophores for early detection were suggested from the literature, among which the most likely are metabolites (phenolics and quinones compounds) of fungi. The results highlight fluorescence spectroscopy as a promising technique for the early diagnosis of fungal diseases in cereal crops.
This work was supported by a grant of the Ministry of Science and Higher Education of the Russian Federation (075-15-2022-315) for the organization and development of a World-class research center "Photonics".
[1] S. Gudkov, T. Matveeva, R. Sarimov, A. Simakin, E. Stepanova, M. Moskovskiy, A. Dorokhov, A. Izmailov, Optical Methods for the Detection of Plant Pathogens and Diseases, Agriengineering, 5(4), pp. 1789-1812, (2023).
[2] S. Gudkov, R. Sarimov, M. Astashev, R. Pishchalnikov, D. Yanykin, A. Simakin, A. Shkirin, D. Serov, E. Konchekov, N. Gusein-zade, Modern physical methods and technologies in agriculture, Uspekhi Fizicheskikh Nauk, 194 (2), pp. 208-226, (2024).
[3] T. Matveyeva, R. Sarimov, A. Simakin, M. Astashev, D. Burmistrov, V. Lednev, P. Sdvizhenskii, M. Grishin, S. Pershin, N. Chilingaryan, N. Semenova, A. Dorokhov, S. Gudkov, Using Fluorescence Spectroscopy to Detect Rot in Fruit and Vegetable Crops, Applied Sciences, 12, pp. 3391, (2022).
