Probing the Metabolic Landscape of Plant Vascular Bundles by Infrared Fingerprint Analysis, Imaging and Mass Spectrometry

Abstract

Fingerprint analysis is a common technique in forensic and criminal investigations. Similar techniques exist in the field of infrared spectroscopy to identify biomolecules according to their characteristic spectral fingerprint features. These unique markers are located in a wavenumber range from 1800 to 600 cm−1 in the mid infrared region. Here, a novel bioanalytical concept of correlating these spectral features with corresponding mass spectrometry datasets to unravel metabolic clusters within complex plant tissues was applied. As proof of concept, vascular bundles of oilseed rape (Brassica napus) were investigated, one of the most important and widely cultivated temperate zone oilseed crops. The link between mass spectrometry data and spectral data identified features that co-aligned within both datasets. Regions of origin were then detected by searching for these features in hyperspectral images of plant tissues. This approach, based on co-alignment and co-localization, finally enabled the detection of eight distinct metabolic clusters, reflecting functional and structural arrangements within the vascular bundle. The proposed analytical concept may assist future synergistic research approaches and may lead to biotechnological innovations with regard to crop yield and sustainability.

Quantitative monitoring of paramagnetic contrast agents and their allocation in plant tissues via DCE-MRI

“…seeds), which would be disturbed if substantial uncontrolled water leakage between xylem vessels and phloem tissue was possible throughout the vascular structure. Similar xylem and phloem associated distribution patterns have also been found for various metabolite groups essential for distinct metabolic functions as recently presented [ 23 ]. This distinct functional compartmentalization, phloem assimilate transport and xylem water transport, essentially follows the same general direction in the stem towards the spike, but is counter directional in leaves (i.e.…”

SWEET11b transports both sugar and cytokinin in developing barley grains

“…4C ). The use of an improved Fourier transform infrared (FTIR) analysis technique ( Guendel et al 2018 , 2021 ) allowed us to not only quantify tZR in cross sections of transgenic and WT grains, but also to examine its spatial distribution. tZR is the transported form of cytokinin ( Kieber and Schaller 2018 ) and represents the bulk of cytokinin molecules in the developing barley grain ( Powell et al 2013 ).…”

“…OPUS files were imported into MATLAB (MathWorks) as ENVI files using the multiband-read function or the irootlab toolbox ( Trevisan et al 2013 ). Spectral features such as carbohydrates and sucrose fingerprints, along with baseline features, were extracted using an extended multiplicative signal correction model adopted into an inhouse developed analytical MATLAB routine for statistical and quantitative spectral feature analysis as described by Guendel et al (2018 , 2021 ). The spectral library used for modeling includes the major plant hormones and some derivatives, a selection of amino acids, secondary metabolites, carbohydrates, lipids and proteins, atmospheric spectra, baseline scatter, and the internal standard ( Supplemental Data Set S3 ).…”

Seeing plants as never before

“…(2017), who were able to visualize the accumulation of sucrose in the vasculature of a germinating oilseed rape seed, as well as the utilization of raffinose, a sugar found only in the embryonic radicle, during the early phase of germination. Finally, an investigation combining sucrose imaging with vascular chemotyping succeeded in establishing that vascular tissues are compartmentalized (Gündel et al ., 2021). FTIR‐based estimates of the mean sucrose concentration in phloem sap were found to correspond well with levels obtained from analysis of the content of aphid styles (Lohaus, 2022).…”