Table 1.
Selected examples of studies in which MSI was used to detect different classes of plant metabolites.
| Chemical class | MSI Source (Ion mode) | Matrix or Spray solvent | Sample | Analyte | Sample preparation | References |
|---|---|---|---|---|---|---|
| Carbohydrates | MALDI (+) | CHCA (in MeOH:H2O, 1:1, + 0.1% FA) | Wheat stem | Oligosaccharides | • Cryosecting (−20°C, 50 μm) and hand sectioning • Matrix applied with airbrush • Double sided tape mounting |
Robinson et al., 2007 |
| MALDI (+) | DHB, CHCA, SA 20 mg/ml (ACN:H2O, 1:1, +0.1% TFA) | Poplar stem | Cellulose | • Cryosecting (−8°C, 50 μm) • Matrix applied with oscillating capillary nebulizer • Double sided tape mounting |
Jung et al., 2010 | |
| MALDI (+) | DHB, 25 mg/ml (in 0.05 mM aqueous sodium acetate) | Poplar stem | Cellulose hemicellulose |
• Microtome sectioning (room temperature, 50 μm) • Matrix applied with Meinhard nebulizer • CryoJane tape mounting |
Lunsford et al., 2011 | |
| MALDI (+) | DHB/DMA, 100 mg/ml (in H2O/ACN/ DMA, 1:1:0.02) | Wheat grain | β-glucan arabinoxylan |
• Vibratome sectioning (in 70% ethanol, 60 μm;) • Sections were stored in 70% ethanol at 4°C until analysis • Matrix applied with ImagePrep • Conductive carbon tape mounting |
Veličković et al., 2014 | |
| IR-MALDI (+) | Native water in the samples | Strawberry | Fructose/glucose sucrose |
• Hand cutting (room temperature, 0.2–0.5 mm) • Fresh sample |
Li et al., 2007b | |
| Organic acids | GALDI (−) | Colloidal graphite (in 2-propanol) | Apple; Strawberry | Malic acid ascorbic acid citric acid quinic acid |
• Cryosecting (liquid nitrogen pre-treated) • Colloidal graphite applied by air spray • Double sided tape mounting |
Zhang et al., 2007 |
| DESI (−) | ACN:H2O (4:1) | Grape leaf petiole | Tartaric acid | • Hand cutting (room temperature, 0.3 mm) • Double sided tape mounting |
Dong et al., 2015 | |
| Lipids and Fatty acids | MALDI (±) | DHB, 50 mg/ml (in MeOH:H2O, 7:3) | Black rice seed | Lysophosphatidylcholine, phosphatidylcholine, Phytic acid gamma-Oryzanol ahpha-Tocopherol | • Cryosecting (-80°C frozen section and freeze imbedded section with 2% CMC at -80°C, 8 μm) • Matrix applied with airbrush • Double sided tape mounting |
Zaima et al., 2010a |
| MALDI (+) | DHB | Cotton seed | Phosphatidylcholines, triacylglycerols, phospholipids | • Cryosecting (unfixed and paraformaldehyde fixed sections, 20°C, 30 μm) • Matrix applied via sublimation |
Horn et al., 2012 | |
| MALDI (−) | DAN | Maize leaf | Glycerolipids | • Cryosecting (freeze imbedded section with gelatin, 10 μm) • Matrix applied via sublimation |
Korte et al., 2015 | |
| LDI (+) | Colloidal silver | A. thaliana leaf & flower | Epicuticular wax | • Vacuum dried (~50 Torr, 30–60 min) • MicroFlow PFA-ST • Nebulizer • Doubly sided tape mounting |
Cha et al., 2009 | |
| MALDI (+) | Lithium-DHB, 20mg/ml (in acetone: dichloromethane, 9:1) | A. thaliana leaf; Date palm tree leaf | Wax esters | • Desiccator dried samples • Matrix applied with airbrush |
Vrkoslav et al., 2010 | |
| Proteins and Peptides | MALDI (+) | Sinapic acid | Soybean cotyledon |
Proteins | • Cryosectioning (10–15 μm) | Grassl et al., 2011 |
| MALDI (+) | Unknown | Barley grain | Proteins | • Unknown | Kaspar et al., 2011 | |
| MALDI (+) | 10 g/L CHCA: 10 g/LAniline (in ACN:H2O:TFA, 50:50:0.1) | Tomato fruit | Protein | • Cryosectioning (5% CMC embedding, 50 μm) • Matrix applied with ImagePrep and dried for 3 h |
Bencivenni et al., 2014 | |
| Terpenoids | LDI (−) | Hypericum leaf, placenta, stamen and stylus | Naphthodianthrones | • Fresh sample or Cryosectioning (60 μm) | Holscher et al., 2009 | |
| DESI (−) | MeOH:H2O, 1:1, +1% ammonium | Hypericum | Hyperforin Hypericin |
• Imprinting on porous Teflon | Thunig et al., 2011 | |
| DESI (−) | 100 uM NH4Cl in MeOH | Red alga* | Bromophycolide A and B | • Preserved with 10% formalin in seawater and kept moist with seawater | Lane et al., 2009 | |
| Alkaloids | MALDI (+) | Saturated CHCA (in methanol) | Capsicum fruit | Capsaicin | • Cryosectioning (−20°C, 70 μm) • Matrix applied with airbrush • Thaw-mounted |
Taira et al., 2012 |
| DESI (−) | MeOH:H2O, 9:1 | Myristica malabarica seed | Malabaricone C | • Imprinting on a printer paper | Ifa et al., 2011 | |
| MALDI (+) | DHB, 30 mg/ml (in MeOH:H2O, 1:1+1%TFA) | Fruiting bodies of M.metata* | 6-Hydroxymetatacarboline D | • Freeze-dried • Matrix applied with ImagePrep • Double sided tape mounting |
Jaeger et al., 2013 | |
| LDI (−) | Tomato leaf | Tomatine | • Imprinting on pencil-lead-coated glass | Li et al., 2014b | ||
| Glycosides | MALDI (−) | 9-aminoacridine 15 mg/ml (MeOH) | A. thaliana leaf | Glucosinolates | • Fresh sample • Matrix applied with airbrush • Double sided tape mounting |
Shroff et al., 2008 |
| MALDI (−) | 9-aminoacridine (neat) | A. thaliana leaf | Glucosinolates | • Fresh sample • Matrix applied via sublimation (170°C, 2 × 10−3 mbar) • Double sided tape mounting |
Shroff et al., 2015 | |
| DESI (+) | MeOH:H2O, 4:1 | Cassava tubers | Gyanogenic glycosides | • Cryosectioning (50 μm) • Thaw-mounted and vacuum dried |
Li et al., 2013 | |
| Phenolics | MALDI (+) | DHB, 50 mg/mL (in MeOH:H2O, 7:3) | Rabbiteye blueberry | Anthocyanins | • Cryosectioning (50 μm) • Matrix applied with airbrush • Thaw-mounted and air dried |
Yoshimura et al., 2012a |
| MALDI (+) | DHB, 50 mg/mL (in MeOH:H2O, 7:3) | Black rice seed | Anthocyanins | • Cryosectioning (freeze-embedded with 2% CMC at −80°C, 10 μm) • Matrix applied with airbrush • Double sided tape mounting |
Yoshimura et al., 2012b | |
| GALDI (−) | Colloidal graphite (in 2-propanol) | A. thaliana leaf, flower and stem | Flavonoids | • Vacuum dried (for leaf and flower, ~50 Torr, 30 min) and cryosectioning (for stem) | Cha et al., 2008; Korte et al., 2012 | |
| SIMS (Bi3+ ion beam) | Pea seed; A. thaliana seed | Flavonoids | • Cryostat sectioning (−20°C, 12 μm) for pea seed • Ultramicrotome sectioning (polyester resin embedding) for A. thaliana seed • Vacuum dried (few hectopascals 15 min) |
Seyer et al., 2010 | ||
| Element | LA-ICP | Elsholtzia splendens leaf | K, P, Mg, Mn, | • Fresh sample | Becker et al., 2008 | |
| Nano-SIMS (Cs+ ion beam) | Rice node, internode and leaf sheath | 12C14N−, 28Si−, 56Fe16O−, 75As−, 32S−, 63Cu−, 31P−, 64Zn16O− | • Samples were coated with 5 nm of platinum • Ultramicrotome sectioning (1 μm) • Sample coated with platinum |
Moore et al., 2014 | ||
| SIMS (gallium ion beam) | Wheat grain | O−, , Mg+, Ca+, Na+, K+ | • Ultramicrotome sectioning (polyester resin embedding) | Heard et al., 2002 |
DMA, N,N-Dimethylaniline; SA, sinapinic acid; DAN, 1,5-Diaminonaphthalene; CAN, acetonitrile; MeOH, methanol; MALDI, matrix assisted laser desorption ionization; LDI, laser desorption ionization; GALDI, graphite assisted laser desorption ionization; DESI, desorption electrospray ionization; SIMS, secondary ion mass spectrometry; LA-ICP, laser ablation inductively coupled plasma.
*
Red alga Callophycus serratus and M. metata are not classified as plant.