Important issues in plant tissues analyses by HR‐MAS NMR

Abstract

The study highlights the need for standardised sample preparation and instrumental setup protocols in order to achieve high reproducibility and obtain reliable data from HR-MAS NMR analyses.

High-Resolution Magic Angle Spinning (HR-MAS) NMR-Based Fingerprints Determination in the Medicinal Plant Berberis laurina

“…In such, NMR spectroscopy is widely used in multidisciplinary “omics”, such as metabolomics, metabolic profiling, fingerprinting, and phenotyping [ 11 , 12 , 13 , 14 ], as well as in identification and structural determination of organic compounds in various samples such as food [ 4 ], ice [ 8 ], serum [ 10 ], environmental [ 15 ], material science [ 16 ], and water [ 17 ]. In addition, high-resolution magic angle spinning (HR-MAS) is a multipurpose NMR tool allowing the acquisition of NMR data directly from semi-solid (i.e., gel-like) materials (e.g., plant tissues) in their natural, unaltered states, without laborious sample preparation steps, and then preventing changes in the chemical composition during these process [ 18 , 19 ]. Moreover, the HR-MAS NMR technique uses specialized HR-MAS probes that allow to collect high-resolution spectra from heterogeneous samples with remarkably similar spectral resolutions as those observed for homogeneous samples in a liquid state (i.e., solution state).…”

“…Therefore, the line-broadening effects coming from dipolar interactions can be minimized by spinning the sample at high spinning rates at the so-called magic angle ( θ MAS = 54.74°) [ 18 , 22 ]. Additionally, in order to improve spectral resolution [ 18 ], the HR-MAS technique is to be applied to the swollen sample in a suitable NMR solvent that provides some molecular motions [ 19 , 22 ]. In addition to the liquid state, HR-MAS NMR has been used in metabolic analyses in human, plant, and food stuff quality managements, genotype, phenotype, and organism cataloging, with interindividual comparisons, environmental toxicity, and pollution [ 24 , 25 , 26 , 27 , 28 , 29 , 30 ].…”

Green (cell) factories for advanced production of plant secondary metabolites

“…The molecules were identified according to their 1 D ( 1 H and 13 C NMR) and 2 D spectra, such as 1 H- 13 C heteronuclear single quantum coherence (HSQC), 1 H-13 C heteronuclear multiple bond correlation (HMBC) and 1 H-1 H correlated spectroscopy (COSY) [51], while for determining the new molecule (labruscol) were used 1 H-1 H rotating frame overhause effect spectroscopy (ROESY) combined with high-resolution electrospray ionization mass spectrometry (HR-ESI-MS) [43]. Precursor feeding with [1-13 C] L-phenylalanine to a V. vinifera cell suspension in a 2-L stirred tank bioreactor lead to the biosynthesis of 13 C labeled stilbenes (trans-and cis-piceids), catechins (catechin and epicatechin) as well as several anthocyanins. The monitoring of these compounds was useful in order to select optimal process parameters and study the metabolic fluxes of the isotopically labeled L-phenylalanine.…”

“…In the era of genome editing, the CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats/CRISPR-associated 9) technology has been used to modify the genes that regulate important biosynthetic pathways in plant in vitro systems aiming to enhance the plant SMs biosynthesis through targeted mutagenesis [11,12]. Metabolomics has been developed as a useful tool for direct chemical insight of the metabolites in heterogenous samples, and as a fundamental part of the current "omics" technologies [13]. It has many applications in life sciences, including plant biology, pharmacology, toxicology, and nutrition [14] aiming to identify the full metabolite complement (untargeted analysis) or measure selected metabolites (targeted analysis) of a cell, tissue, biofluid, or organism [13].…”

“…Metabolomics has been developed as a useful tool for direct chemical insight of the metabolites in heterogenous samples, and as a fundamental part of the current "omics" technologies [13]. It has many applications in life sciences, including plant biology, pharmacology, toxicology, and nutrition [14] aiming to identify the full metabolite complement (untargeted analysis) or measure selected metabolites (targeted analysis) of a cell, tissue, biofluid, or organism [13]. Analyses on plant in vitro systems, when integrated with "omics" technologies, provide an enormous advantage for the study of cellular processes, gene functions and metabolites network alterations under environmental stimuli.…”