A comparative transcriptomic study and a single-cell metabolome analysis were combined to determine whether parenchymal ray cells contribute to the biosynthesis of monolignols in the lignifying xylem of Norway spruce (Picea abies). Ray parenchymal cells may function in the lignification of upright tracheids by supplying monolignols. To test this hypothesis, parenchymal ray cells and upright tracheids were dissected with laser-capture microdissection from tangential cryosections of developing xylem of spruce trees. The transcriptome analysis revealed that among the genes involved in processes typical for vascular tissues, genes encoding cell wall biogenesis-related enzymes were highly expressed in both developing tracheids and ray cells. Interestingly, most of the shikimate and monolignol biosynthesis pathway-related genes were equally expressed in both cell types. Nonetheless, 1,073 differentially expressed genes were detected between developing ray cells and tracheids, among which a set of genes expressed only in ray cells was identified. In situ single cell metabolomics of semi-intact plants by picoliter pressure probe-electrospray ionization-mass spectrometry detected monolignols and their glycoconjugates in both cell types, indicating that the biosynthetic route for monolignols is active in both upright tracheids and parenchymal ray cells. The data strongly support the hypothesis that in developing xylem, ray cells produce monolignols that contribute to lignification of tracheid cell walls.
© 2019 American Society of Plant Biologists. All Rights Reserved.
Cloning, characterization and localization of three novel class III peroxidases in lignifying xylem of Norway spruce (Picea abies).Plant Mol Biol. 2006 Jul;61(4-5):719-32. doi: 10.1007/s11103-006-0043-6. Plant Mol Biol. 2006. PMID: 16897487
Laser Capture Microdissection Protocol for Xylem Tissues of Woody Plants.Front Plant Sci. 2017 Jan 4;7:1965. doi: 10.3389/fpls.2016.01965. eCollection 2016. Front Plant Sci. 2017. PMID: 28101088 Free PMC article.
Transcriptional Roadmap to Seasonal Variation in Wood Formation of Norway Spruce.Plant Physiol. 2018 Apr;176(4):2851-2870. doi: 10.1104/pp.17.01590. Epub 2018 Feb 27. Plant Physiol. 2018. PMID: 29487121 Free PMC article.
Trends in lignin modification: a comprehensive analysis of the effects of genetic manipulations/mutations on lignification and vascular integrity.Phytochemistry. 2002 Oct;61(3):221-94. doi: 10.1016/s0031-9422(02)00211-x. Phytochemistry. 2002. PMID: 12359514 Review.
Cell wall lignin is polymerised by class III secretable plant peroxidases in Norway spruce.J Integr Plant Biol. 2010 Feb;52(2):186-94. doi: 10.1111/j.1744-7909.2010.00928.x. J Integr Plant Biol. 2010. PMID: 20377680 Review.
Cited by 1 article
On-site single pollen metabolomics reveals varietal differences in phosphatidylinositol synthesis under heat stress conditions in rice.Sci Rep. 2020 Feb 6;10(1):2013. doi: 10.1038/s41598-020-58869-9. Sci Rep. 2020. PMID: 32029818 Free PMC article.