UPSC-0016
Are lignin monomers secreted from ray parenchymal cells in lignifying norway spruce     xylem?
In Norway spruce (Picea abies L.Karst.) lignin forms a major part of the xylem     cell walls and renders the tracheids water resistant while giving support to the cell walls and     the whole tree trunk. In Norway spruce lignin is polymerized mainly of coniferyl alcohol but the     origins of this monolignol is not known. In the present investigation we examined the     possibility whether coniferyl alcohol is produced in the ray parenchymal cells similarly to that     in angiosperms where neighboring cells contribute to biosynthesis of monolignols used for lignin     formation in tracheary elements (Pesquet et al. 2013, Smith et al. 2013). Hence, we used Zeiss     PALM MicroBeam laser capture microdissection instrument to isolate ray parenchyma from thin     tangential cryomicrotome sections (30um) of developing Norway spruce xylem of a mature tree.     Total RNA extracted from the collected material was used for low input sequencing on Illumina     platform to reveal any transcripts related to monolignol biosynthesis and secretion. As a     control material we used xylem tracheid cells isolated from similar cryomicrotome sections. The     deep sequencing protocol gives also information on the mRNA frequency in a particular cell type.     The results are mapped to the whole genome sequencing data of Norway spruce to identify the key     genes that are active in these tissues during xylem development and to characterize cell     type-specific monolignol synthesis and transport.
In Norway spruce (Picea abies L.Karst.) lignin forms a major part of the xylem     cell walls and renders the tracheids water resistant while giving support to the cell walls and     the whole tree trunk. In Norway spruce lignin is polymerized mainly of coniferyl alcohol but the     origins of this monolignol is not known. In the present investigation we examined the     possibility whether coniferyl alcohol is produced in the ray parenchymal cells similarly to that     in angiosperms where neighboring cells contribute to biosynthesis of monolignols used for lignin     formation in tracheary elements (Pesquet et al. 2013, Smith et al. 2013). Hence, we used Zeiss     PALM MicroBeam laser capture microdissection instrument to isolate ray parenchyma from thin     tangential cryomicrotome sections (30um) of developing Norway spruce xylem of a mature tree.     Total RNA extracted from the collected material was used for low input sequencing on Illumina     platform to reveal any transcripts related to monolignol biosynthesis and secretion. As a     control material we used xylem tracheid cells isolated from similar cryomicrotome sections. The     deep sequencing protocol gives also information on the mRNA frequency in a particular cell type.     The results are mapped to the whole genome sequencing data of Norway spruce to identify the key     genes that are active in these tissues during xylem development and to characterize cell     type-specific monolignol synthesis and transport.