Tissue‐specific study across the stem reveals the chemistry and transcriptome dynamics of birch bark

Abstract

Summary Tree bark is a highly specialized array of tissues that plays important roles in plant protection and development. Bark tissues develop from two lateral meristems; the phellogen (cork cambium) produces the outermost stem–environment barrier called the periderm, while the vascular cambium contributes with phloem tissues. Although bark is diverse in terms of tissues, functions and species, it remains understudied at higher resolution. We dissected the stem of silver birch (Betula pendula) into eight major tissue types, and characterized these by a combined transcriptomics and metabolomics approach. We further analyzed the varying bark types within the Betulaceae family. The two meristems had a distinct contribution to the stem transcriptomic landscape. Furthermore, inter‐ and intraspecies analyses illustrated the unique molecular profile of the phellem. We identified multiple tissue‐specific metabolic pathways, such as the mevalonate/betulin biosynthesis pathway, that displayed differential evolution within the Betulaceae. A detailed analysis of suberin and betulin biosynthesis pathways identified a set of underlying regulators and highlighted the important role of local, small‐scale gene duplication events in the evolution of metabolic pathways. This work reveals the transcriptome and metabolic diversity among bark tissues and provides insights to its development and evolution, as well as its biotechnological applications.

Comparative transcriptome analysis of root, stem, and leaf tissues of Entada phaseoloides reveals potential genes involved in triterpenoid saponin biosynthesis

“…The high expression of β-amyrin synthase, an important enzyme related to triterpenoid sapogenin biosynthesis at later stages, further reveals the high concentration of sapogenins in the stem of Entada phaseoloides. Similar tissuespeci c concentrations of triterpenoid sapogenins have already been reported in other plants [43][44][45]. Moreover, 26 CYP450s and 17 UGTs were found to be upregulated in the stem.…”

Gene co-expression analysis and tissue-specific gene identification in Liriodendron chinense via hybrid sequencing

“…By analysing the DEGs in the root, researchers revealed the pathway of tanshinone biosynthesis in S. miltiorrhiza [29]. Tissue-speci c genes, play important roles in plant defence, stress response, plant development and material metabolism [41,42,[80][81][82][83]. In Ferula asafetida, genes involved in terpenoid and phenylpropanoid metabolism tended to be expressed in the owers [83].…”

Genome-Wide Analysis of NAC Gene Family in Betula pendula

“…We collected five leaves from each individual and mixed them together as one biological replicate. For xylem, we used the upper stem (about 10th nodes) of two-year old birch trees, and the tissue-specific sampling was performed, according to the Juan Alonso-Serra et al [52] method. Sequential tangential cryosections were collected with two biological replicates per fraction and processed independently.…”