Confirmatory detection and identification of biotic and abiotic stresses in wheat using Raman spectroscopy

Abstract

Wheat is one of the oldest and most widely cultivated staple food crops worldwide. Wheat encounters an array of biotic and abiotic stresses during its growth that significantly impact the crop yield and consequently global food security. Molecular and imaging methods that can be used to detect such stresses are laborious and have numerous limitations. This catalyzes the search for alternative techniques that can be used to monitor plant health. Raman spectroscopy (RS) is a modern analytical technique that is capable of probing structure and composition of samples non-invasively and non-destructively. In this study, we investigate the accuracy of RS in confirmatory diagnostics of biotic and abiotic stresses in wheat. Specifically, we modelled nitrogen deficiency (ND) and drought, key abiotic stresses, and Russian wheat aphid (Diuraphis noxia) infestation and viral diseases: wheat streak mosaic virus (WSMV) and Triticum mosaic virus (TriMV), economically significant biotic stresses in common bread wheat. Raman spectra as well as high pressure liquid chromatography (HPLC)-based analyses revealed drastically distinct changes in the intensity of carotenoid vibration (1185 cm-1) and in the concentration of lutein, chlorophyll, and pheophytin biomolecules of wheat, triggered in response to aforementioned biotic and abiotic stresses. The biochemical changes were reflected in unique vibrational signatures in the corresponding Raman spectra, which, in turn could be used for ~100% accurate identification of biotic and abiotic stresses in wheat. These results demonstrate that a hand-held Raman spectrometer could provide an efficient, scalable, and accurate diagnosis of both biotic as well as abiotic stresses in the field.

Diagnosing arsenic-mediated biochemical responses in rice cultivars using Raman spectroscopy

“…The Raman spectra collected from rice leaves contained several peaks that corresponded to different biomolecules, such as carotenoids (1003, 1155, 1185, 1213, 1525 cm -1 ), phenylpropanoids (1604, 1632 cm -1 ), cellulose (917, 1048 cm -1 ), carbohydrates (1155 cm -1 ), and pectin (747 cm -1 ) ( Sanchez et al., 2020 ; Higgins et al., 2022a , Higgins et al., 2022b ) ( Figure 1 ). The peaks at 1286, 1326, 1386, and 1440 cm -1 could be assigned to CH and CH 2 vibrations, which are present in nearly all classes of biological molecules.…”

“…HPLC was performed to quantify the amount of carotenoids and phenylpropanoids in all groups of plants. Carotenoids were extracted by homogenizing 150 mg of rice leaf tissue with a mortar and pestle ( Higgins et al., 2022b ). 1.5 mL of a 1:2 v/v dichloromethane:chloroform mixture was added to the homogenized plant tissue, and the resultant solution was mixed on a thermomixer for 30 minutes at 4°C and 500 rpm.…”

Elucidation of sex from mature Palmer amaranth (Amaranthus palmeri) leaves using a portable Raman spectrometer

“…By measuring the scattered light, it can reveal detailed molecular fingerprint information, allowing for the characterization and discrimination of various compounds. In the context of agriculture, RS has been successfully applied in diverse areas such as crop disease diagnosis, 5 nutrient analysis, 6 pesticide residue detection, 7,8 and quality assessment of agricultural products. 9 Of present concern, Higgins et al (2022) used a portable Raman spectrometer to accurately identify the sex of mature hemp plants by scanning their leaves.…”

Brevibacillus choshinensis Restricts Harmful Eurygaster integriceps in Wheat-Sown Fields and Enhances Beneficial Insect Population

“…Likewise, the fact that it is an important food product grown in arid and semi-arid regions increases its value even more. However, although it has a wide adaptation ability, various biotic and abiotic stress factors reduce wheat yield and quality, and sometimes lead to no crops (Çığ et al 2022;Higgins et al 2022).…”