PT - JOURNAL ARTICLE AU - Pesquet, Edouard AU - Zhang, Bo AU - Gorzsás, András AU - Puhakainen, Tuula AU - Serk, Henrik AU - Escamez, Sacha AU - Barbier, Odile AU - Gerber, Lorenz AU - Courtois-Moreau, Charleen AU - Alatalo, Edward AU - Paulin, Lars AU - Kangasjärvi, Jaakko AU - Sundberg, Björn AU - Goffner, Deborah AU - Tuominen, Hannele TI - Non-Cell-Autonomous Postmortem Lignification of Tracheary Elements in <em>Zinnia elegans</em> AID - 10.1105/tpc.113.110593 DP - 2013 Apr 01 TA - The Plant Cell PG - 1314--1328 VI - 25 IP - 4 4099 - http://www.plantcell.org/content/25/4/1314.short 4100 - http://www.plantcell.org/content/25/4/1314.full SO - Plant Cell2013 Apr 01; 25 AB - Postmortem lignification of xylem tracheary elements (TEs) has been debated for decades. Here, we provide evidence in Zinnia elegans TE cell cultures, using pharmacological inhibitors and in intact Z. elegans plants using Fourier transform infrared microspectroscopy, that TE lignification occurs postmortem (i.e., after TE programmed cell death). In situ RT-PCR verified expression of the lignin monomer biosynthetic cinnamoyl CoA reductase and cinnamyl alcohol dehydrogenase in not only the lignifying TEs but also in the unlignified non-TE cells of Z. elegans TE cell cultures and in living, parenchymatic xylem cells that surround TEs in stems. These cells were also shown to have the capacity to synthesize and transport lignin monomers and reactive oxygen species to the cell walls of dead TEs. Differential gene expression analysis in Z. elegans TE cell cultures and concomitant functional analysis in Arabidopsis thaliana resulted in identification of several genes that were expressed in the non-TE cells and that affected lignin chemistry on the basis of pyrolysis–gas chromatography/mass spectrometry analysis. These data suggest that living, parenchymatic xylem cells contribute to TE lignification in a non-cell-autonomous manner, thus enabling the postmortem lignification of TEs.GlossaryTEtracheary elementPCDprogrammed cell deathPApiperonylic acidFT-IRFourier transform infraredSTSsilver thiosulfateTUNELterminal deoxynucleotidyl transferase dUTP nick end labelingSSHsuppression subtractive hybridizationROSreactive oxygen speciesNACN-acetylcysteineCatcatalaseDPIdiphenylene iodoniumGUSβ-glucuronidasePy-GC/MSpyrolysis–gas chromatography/mass spectrometryFITCfluorescein isothiocyanateSEsingle-elementFPAfocal plane arrayANOVAanalysis of varianceCtcycle thresholdTMRAtetramethylrhodamine anhydride