Matrix-free UV-laser desorption/ionization (LDI) mass spectrometric imaging at the single-cell level: distribution of secondary metabolites of Arabidopsis thaliana and Hypericum species.
The present paper describes matrix-free laser desorption/ionisation mass spectrometric imaging (LDI-MSI) of highly localized UV-absorbing secondary metabolites in plant tissues at single-cell resolution. The scope and limitations of the method are discussed with regard to plants of the genus Hypericum. Naphthodianthrones such as hypericin and pseudohypericin are traceable in dark glands on Hypericum leaves, placenta, stamens and styli; biflavonoids are also traceable in the pollen of this important phytomedical plant. The highest spatial resolution achieved, 10 microm, was much higher than that achieved by commonly used matrix-assisted laser desorption/ionization (MALDI) imaging protocols. The data from imaging experiments were supported by independent LDI-TOF/MS analysis of cryo-sectioned, laser-microdissected and freshly cut plant material. The results confirmed the suitability of combining laser microdissection (LMD) and LDI-TOF/MS or LDI-MSI to analyse localized plant secondary metabolites. Furthermore, Arabidopsis thaliana was analysed to demonstrate the feasibility of LDI-MSI for other commonly occurring compounds such as flavonoids. The organ-specific distribution of kaempferol, quercetin and isorhamnetin, and their glycosides, was imaged at the cellular level.
Hölscher
Dirk
D
Department of Entomology, Mass Spectrometry Research Group, Biosynthesis/NMR Research Group, Max Planck Institute for Chemical Ecology, Hans-Knöll-Strasse 8, 07745 Jena, Germany. svatos@ice.mpg.de
Shroff
Rohit
R
Knop
Katrin
K
Gottschaldt
Michael
M
Crecelius
Anna
A
Schneider
Bernd
B
Heckel
David G
DG
Schubert
Ulrich S
US
Svatos
Ales
A
D017360:Arabidopsis / Q000737:chemistry* / Q000166:cytology / Q000378:metabolism; D044948:Flavonols / Q000032:analysis / Q000737:chemistry / Q000378:metabolism; D006027:Glycosides / Q000032:analysis / Q000737:chemistry / Q000378:metabolism; D020902:Hypericum / Q000737:chemistry* / Q000166:cytology / Q000378:metabolism; D044949:Kaempferols / Q000032:analysis / Q000737:chemistry / Q000378:metabolism; D013058:Mass Spectrometry / Q000379:methods*; D011794:Quercetin / Q000032:analysis / Q000737:chemistry / Q000378:metabolism / Q000031:analogs & derivatives
D044948:Flavonols; D006027:Glycosides; D044949:Kaempferols; C047368:3-methylquercetin; C006552:kaempferol; D011794:Quercetin