Tracing the fate and transport of secondary plant metabolites in a laboratory mesocosm experiment by employing mass spectrometric imaging

Abstract

Mass spectrometric imaging (MSI) has received considerable attention in recent years, since it allows the molecular mapping of various compound classes, such as proteins, peptides, glycans, secondary metabolites, lipids, and drugs in animal, human, or plant tissue sections. In the present study, the application of laser-based MSI analysis of secondary plant metabolites to monitor their transport from the grass leaves of Dactylis glomerata, over the crop of the grasshopper Chorthippus dorsatus to its excrements, and finally in the soil solution is described. This plant-herbivore-soil pathway was investigated under controlled conditions by using laboratory mesocosms. From six targeted secondary plant metabolites (dehydroquinic acid, quinic acid, apigenin, luteolin, tricin, and rosmarinic acid), only quinic acid, and dehydroquinic acid, an in-source-decay (ISD) product of quinic acid, could be traced in nearly all compartments. The tentative identification of secondary plant metabolites was performed by MS/MS analysis of methanol extracts prepared from the investigated compartments, in both the positive and negative ion mode, and subsequently compared with the results generated from the reference standards. Except for tricin, all secondary metabolites could be tentatively identified by this approach. Additional liquid-chromatography mass spectrometry (LC-MS) experiments were carried out to verify the MSI results and revealed the presence of quinic acid only in grass and chewed grass, whereas apigenin-hexoside-pentoside and luteolin-hexoisde-pentoside could be traced in the grasshopper body and excrement extracts. In summary, the MSI technique shows a trade-off between sensitivity and spatial resolution. Graphical abstractMonitoring quinic acid in a mesocosm experiment by mass spectrometric imaging (MSI). Electronic supplementary materialThe online version of this article (doi:10.1007/s00216-017-0325-7) contains supplementary material, which is available to authorized users.

Acylated Quinic Acids Are the Main Salicortin Metabolites in the Lepidopteran Specialist Herbivore Cerura vinula

“…The conjugation with quinic acids is described here for the first time as part of a detoxification pathway. Quinic acid has been reported to play a role in response to herbivory (Wang et al 2016), and quinic acids were detected in the gut of insects (Crecelius et al 2017). It was also suggested that quinic acid conjugates like chlorogenic acid produce feeding-deterrent compounds after cleavage and oxidative transformation of the phenylpropanoic part (Stevenson et al 1993).…”

Mass Spectrometry Imaging: A Review of Emerging Advancements and Future Insights

“…36 Because of their structure, metabolites can have poor ionization efficiency, which has prompted the development of many derivatization schemes to increase access to metabolites in samples. 28,31,53 Just like lipids, a wide variety of ionization techniques lends well to metabolites, including MALDI, 12,14,20,28,29,31,36,137,233–236 DESI, 2,218,237 and LAESI, 69 although, based upon citations alone, MALDI is by far the most popular. This is actually surprising, as most matrixes used for MALDI analysis are small organic compounds, meaning they can have their own interfering ions in the metabolite mass range at high concentrations, masking some possible signals of interest.…”

Mass spectrometry imaging: An emerging technology for the analysis of metabolites in insects

“…Furthermore, understanding the entire metabolic process of secondary metabolites in the plant–insect–soil system makes MSI more appealing. Crecelius et al () using LDI tracked the fate of secondary metabolites produced by grass ( Dactylis glomerate ), in grasshoppers ( Chorthippus dorsatus ) over the digestion process to its excrements and finally in the soil solution. The results showed that in the leaf wounds of plants, quinic acid, apigenin, and luteolin decreased after a day of feeding, whereas the flavonoids and rosmarinic acid increased.…”

“…MSI has been applied to insect tissue section for in situ characterization of three major aspects, endogenous metabolites (including lipids, neuropeptides, proteins, and defense compounds; Bhandari, Schott, Römpp, Vilcinskas, & Spengler, ; Catae et al, ; Ly et al, ; Marty et al, ), exogenous metabolites (drugs and insecticides; Ohtsu, Yamaguchi, Nishiwaki, Fukusaki, & Shimma, ; Olsen, Hansen, & Janfelt, ), and insect–plant interactions (tracking the fate of plant secondary defense compounds; Crecelius, Michalzik, Potthast, Meyer, & Schubert, ). How insects rapidly adapt to host plant, how insects are resistant to insecticides, and how insects interact with gut microbes have recently become hot topics in insect sciences.…”

“…(f) Hematoxylin-eosin staining displaying tissue localization characteristic. MALDI-MSI, matrix-assisted laser desorption ionization-mass spectrometry imaging insect-plant interactions (tracking the fate of plant secondary defense compounds; Crecelius, Michalzik, Potthast, Meyer, & Schubert, 2017). How insects rapidly adapt to host plant, how insects are resistant to insecticides, and how insects interact with gut microbes have recently become hot topics in insect sciences.…”