Transcriptional Regulation of Secondary Growth and Wood Formation

The majority of detailed studies on circumnutational growth movements have focused on herbaceous plants or on the primary growth of woody plant seedlings, ignoring completely secondary growth in woody plants. The relatively rapid movement in herbaceous tissues consists of two components: an autonomous growth rhythm and a gravitropic response. Since there is a gravitropic component to circumnutational movement and a gravitropic stimulus can induce compression wood formation, the formation of a compression wood spiral may be expected if there is a circumnutational movement of a woody stern. It is suggested here, that observed spirals of compression wood within annual growth rings in Pinus taeda L. and Abies concolor (Gord. ' Glend.) Lindl. ex Hildebr. represents an annual record of a slower circumnutational growth movement. Data derived from observations of greenhouse- grown 3-year-old Pinus taeda seedlings indicate that there are two distinct circumnutational patterns of different rotation al frequency present in woody plants associated with primary and secondary tissues.

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Transcriptional regulation of secondary growth in Arabidopsis thaliana

Journal of Experimental Botany ◽

10.1093/jxb/erg304 ◽

2003 ◽

Vol 54 (393) ◽

pp. 2709-2722 ◽

Cited By ~ 107

Author(s):

Sookyung Oh ◽

Sunchung Park ◽

Kyung-Hwan Han

Keyword(s):

Arabidopsis Thaliana ◽

Transcriptional Regulation ◽

Secondary Growth

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PSDX: A Comprehensive Multi-Omics Association Database of Populus trichocarpa With a Focus on the Secondary Growth in Response to Stresses

Frontiers in Plant Science ◽

10.3389/fpls.2021.655565 ◽

2021 ◽

Vol 12 ◽

Author(s):

Huiyuan Wang ◽

Sheng Liu ◽

Xiufang Dai ◽

Yongkang Yang ◽

Yunjun Luo ◽

...

Keyword(s):

Gene Expression ◽

Transcriptional Regulation ◽

Transcription Initiation ◽

High Throughput Sequencing ◽

Rna Binding ◽

Rna Binding Proteins ◽

Populus Trichocarpa ◽

Secondary Growth ◽

A Genome ◽

Post Transcriptional Regulation

Populus trichocarpa (P. trichocarpa) is a model tree for the investigation of wood formation. In recent years, researchers have generated a large number of high-throughput sequencing data in P. trichocarpa. However, no comprehensive database that provides multi-omics associations for the investigation of secondary growth in response to diverse stresses has been reported. Therefore, we developed a public repository that presents comprehensive measurements of gene expression and post-transcriptional regulation by integrating 144 RNA-Seq, 33 ChIP-seq, and six single-molecule real-time (SMRT) isoform sequencing (Iso-seq) libraries prepared from tissues subjected to different stresses. All the samples from different studies were analyzed to obtain gene expression, co-expression network, and differentially expressed genes (DEG) using unified parameters, which allowed comparison of results from different studies and treatments. In addition to gene expression, we also identified and deposited pre-processed data about alternative splicing (AS), alternative polyadenylation (APA) and alternative transcription initiation (ATI). The post-transcriptional regulation, differential expression, and co-expression network datasets were integrated into a new P. trichocarpa Stem Differentiating Xylem (PSDX) database, which further highlights gene families of RNA-binding proteins and stress-related genes. The PSDX also provides tools for data query, visualization, a genome browser, and the BLAST option for sequence-based query. Much of the data is also available for bulk download. The availability of PSDX contributes to the research related to the secondary growth in response to stresses in P. trichocarpa, which will provide new insights that can be useful for the improvement of stress tolerance in woody plants.

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Expression and localization of SWEETs in Populus and the effect of SWEET7 overexpression in secondary growth

Tree Physiology ◽

10.1093/treephys/tpaa145 ◽

2020 ◽

Author(s):

Li Zhang ◽

Lijuan Wang ◽

Jin Zhang ◽

Cai Song ◽

Yu Li ◽

...

Keyword(s):

Populus Trichocarpa ◽

Sugar Content ◽

Expression Patterns ◽

Secondary Growth ◽

Wood Formation ◽

Pcr Analysis ◽

Sugar Transporters ◽

Real Time Quantitative Pcr ◽

Physiological Processes ◽

Gene Structures

Abstract In trees, wood formation needs carbon import from the photosynthetic source tissues. Sugar transporters play important roles in carbohydrate transport into wood-forming cells. SWEETs (Sugars Will Eventually be Exported Transporters) play essential roles in many physiological processes. However, the roles of this family in the growth and development of woody plants have not been systematically investigated. In this study, 27 SWEET genes were identified in the Populus trichocarpa genome. These SWEET genes were classified into four clades based on their phylogenetic relationships, gene structures, conserved motifs, and chromosomal locations. Representative SWEET members from each clade were selected for further studies. The PagSWEETs were localized to plasma membrane, vacuolar, endoplasmic reticulum (ER) or Golgi. Real-time quantitative PCR analysis showed that PagSWEETs have distinct expression patterns in various tissues, and PagSWEET5, 7, 10b, 10c, 15b, 17a, and 17c exhibited high expression levels in stems. PagSWEET7 is localized to the cytoplasmic membrane and specifically expressed in the phloem as detected by histochemical GUS assays. Xylem production and xylem sugar content were greater in developing wood of SWEET7 overexpression (OX) than Wild-type (WT) lines. Collectively, these results provide valuable information for further investigating functions of PagSWEET genes, and identify PagSWEET7 as a candidate gene for using biotechnology to modify the wood formation in poplar.

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Bud and cambial zone phenology of lateral branches from Douglas-fir (Pseudotsugamenziesii) seedlings

Canadian Journal of Forest Research ◽

10.1139/x94-041 ◽

1994 ◽

Vol 24 (2) ◽

pp. 286-296 ◽

Cited By ~ 6

Author(s):

K.H. Rensing ◽

J.N. Owens

Keyword(s):

Cell Division ◽

Secondary Growth ◽

Morphological Characteristics ◽

Wood Formation ◽

Douglas Fir ◽

Winter Period ◽

Cambial Cell ◽

Leaf Initiation ◽

Cambial Zone ◽

Cambial Cells

Bud and cambial zone phenologies of outdoor-grown, containerized seedlings of Pseudotsugamenziesii (Mirb.) Franco (Douglas-fir) were determined and compared. Morphological characteristics of the live primordial shoots were related to known stages of bud development, while cambial zone phenology was based on anatomical characteristics. Secondary growth in branches of P. menziesii seedlings was separated into six stages: (i) early wood formation; (ii) latewood formation; (iii) cessation of cambial cell division; (iv) dormancy; (v) cambial cell expansion; and (vi) resumption of cell division. Early wood formation by the cambial zone, and primary leaf initiation in the shoot tips occurred until July. During this time of maximal activity, differences in wall thickness and shape distinguished cambial cells from vascular cells in early differentiation stages. By late July, earlywood formation was changing to latewood formation and bud-scale initiation had begun. The transition to preformed leaf initiation in the buds occurred over a period of 1 month in August and September. Cambial cell division ceased in early September but tracheid differentiation continued until about the end of October. Preformed leaf initiation lasted until the buds became dormant in mid-November. The cambial zone was dormant from the end of November until the beginning of March, and in transverse section was characterized by a distinct boundary at the border of the xylem and regular, cigar-shaped cambial cells with thick radial walls. Resumption of cambial activity in the 1st week of April began with radial expansion, followed about 2 weeks later by cell division. Differentiation of earlywood tracheids and bud swelling began in early April. The majority of buds flushed in the 3rd week of April. Rays in the lateral shoots were composed of monoseriate files of radially elongated cells. Ray initials were not observed. Ultrastructural features indicated that the dictyosomes of the cambial cells were active during the winter period.

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Learning from the past – the origin of wood

The Forestry Chronicle ◽

10.5558/tfc84498-4 ◽

2008 ◽

Vol 84 (4) ◽

pp. 498-503 ◽

Cited By ~ 3

Author(s):

Rodney Arthur Savidge

Keyword(s):

Cell Biology ◽

Secondary Xylem ◽

Secondary Growth ◽

Wood Formation ◽

Late Triassic ◽

Primary Xylem ◽

Tree Ferns ◽

Severe Climate Change ◽

Middle Carboniferous ◽

Extinction Events

Trees were on Earth 394 million years ago (394 Ma) as spore-producing Archaeopteris progymnosperms having largediameter trunks of secondary xylem (morphotype Callixyon) produced by vascular cambium. Plants of smaller stature with primary xylem cores were present in Late Silurian (416 Ma), but they lacked cambium and it remains unclear how and when the first trees evolved. Progymnosperms faded and gymnosperms arose during Middle Carboniferous, and conifers, ginkgos, cycads, tree ferns and cordaites were well established by the Carboniferous–Permian transition (299 Ma). Woods of the earliest conifers were different from those of today, and not until Late Triassic (220 Ma) did any begin producing secondary xylem similar to modern woods, the xylem phenotypes of Cupressaceae and Araucariaceae emerging much earlier than those of Pinaceae and flowering plants. Conifers have persisted and done relatively well despite major extinction events, severe climate change, insectivory, herbivory and microbial activity, all of which were in effect before as well as during the appearance of trees on Earth. Approximately 600 conifer species continue to exist, and the survivors presumably possess the physiological fitness needed to adapt to an ever-changing biosphere. However, this is speculative because their physiology remains less than well understood. Forestry interventions such as planting one species to the exclusion of others have the potential to exacerbate as well as sustain the ongoing existence of our remaining conifers. Key words: bordered pit, cambium, cell biology, cellulose, evolution, lignin, paleobotany, protoplasmic autolysis, secondary growth, wood formation, xylogenesis

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The Transcriptomics of Secondary Growth and Wood Formation in Conifers

Molecular Biology International ◽

10.1155/2013/974324 ◽

2013 ◽

Vol 2013 ◽

pp. 1-12 ◽

Cited By ~ 12

Author(s):

Ana Carvalho ◽

Jorge Paiva ◽

José Louzada ◽

José Lima-Brito

Keyword(s):

Picea Glauca ◽

Draft Genome ◽

Secondary Growth ◽

Wood Formation ◽

Gradual Improvement ◽

Whole Genomes ◽

Conifer Genome ◽

Genome Assemblies ◽

Next Generation Sequencing Ngs ◽

Selection Of

In the last years, forestry scientists have adapted genomics and next-generation sequencing (NGS) technologies to the search for candidate genes related to the transcriptomics of secondary growth and wood formation in several tree species. Gymnosperms, in particular, the conifers, are ecologically and economically important, namely, for the production of wood and other forestry end products. Until very recently, no whole genome sequencing of a conifer genome was available. Due to the gradual improvement of the NGS technologies and inherent bioinformatics tools, two draft assemblies of the whole genomes sequence of Picea abies and Picea glauca arose in the current year. These draft genome assemblies will bring new insights about the structure, content, and evolution of the conifer genomes. Furthermore, new directions in the forestry, breeding and research of conifers will be discussed in the following. The identification of genes associated with the xylem transcriptome and the knowledge of their regulatory mechanisms will provide less time-consuming breeding cycles and a high accuracy for the selection of traits related to wood production and quality.

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Transcriptional regulation in wood formation

Trends in Plant Science ◽

10.1016/j.tplants.2006.12.006 ◽

2007 ◽

Vol 12 (2) ◽

pp. 64-70 ◽

Cited By ~ 141

Author(s):

Taku Demura ◽

Hiroo Fukuda

Keyword(s):

Transcriptional Regulation ◽

Wood Formation

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Exogenous Brassinosteroid Facilitates Xylem Development in Pinus massoniana Seedlings

International Journal of Molecular Sciences ◽

10.3390/ijms22147615 ◽

2021 ◽

Vol 22 (14) ◽

pp. 7615

Author(s):

Fuhua Fan ◽

Zijing Zhou ◽

Huijuan Qin ◽

Jianhui Tan ◽

Guijie Ding

Keyword(s):

Molecular Mechanisms ◽

Lignin Content ◽

Secondary Growth ◽

Pinus Massoniana ◽

Wood Formation ◽

Dependent Manner ◽

Xylem Development ◽

Lignin Synthesis ◽

Phenylpropanoid Biosynthesis ◽

Endogenous Phytohormone

Brassinosteroids (BRs) are known to be essential regulators for wood formation in herbaceous plants and poplar, but their roles in secondary growth and xylem development are still not well-defined, especially in pines. Here, we treated Pinus massoniana seedlings with different concentrations of exogenous BRs, and assayed the effects on plant growth, xylem development, endogenous phytohormone contents and gene expression within stems. Application of exogenous BR resulted in improving development of xylem more than phloem, and promoting xylem development in a dosage-dependent manner in a certain concentration rage. Endogenous hormone determination showed that BR may interact with other phytohormones in regulating xylem development. RNA-seq analysis revealed that some conventional phenylpropanoid biosynthesis- or lignin synthesis-related genes were downregulated, but the lignin content was elevated, suggesting that new lignin synthesis pathways or other cell wall components should be activated by BR treatment in P. massoniana. The results presented here reveal the foundational role of BRs in regulating plant secondary growth, and provide the basis for understanding molecular mechanisms of xylem development in P. massoniana.

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Wood Formation under Severe Drought Invokes Adjustment of the Hormonal and Transcriptional Landscape in Poplar

International Journal of Molecular Sciences ◽

10.3390/ijms22189899 ◽

2021 ◽

Vol 22 (18) ◽

pp. 9899

Author(s):

Dade Yu ◽

Dennis Janz ◽

Krzysztof Zienkiewicz ◽

Cornelia Herrfurth ◽

Ivo Feussner ◽

...

Keyword(s):

Cell Wall ◽

Secondary Growth ◽

Wood Formation ◽

Severe Drought ◽

Normal Wood ◽

Aba Signaling ◽

Negative Effects ◽

Transcriptional Responses ◽

Cell Wall Modification ◽

Induced Changes

Drought is a severe environmental stress that exerts negative effects on plant growth. In trees, drought leads to reduced secondary growth and altered wood anatomy. The mechanisms underlying wood stress adaptation are not well understood. Here, we investigated the physiological, anatomical, hormonal, and transcriptional responses of poplar to strong drought. Drought-stressed xylem was characterized by higher vessel frequencies, smaller vessel lumina, and thicker secondary fiber cell walls. These changes were accompanied by strong increases in abscisic acid (ABA) and antagonistic changes in salicylic acid in wood. Transcriptional evidence supported ABA biosynthesis and signaling in wood. Since ABA signaling activates the fiber-thickening factor NST1, we expected upregulation of the secondary cell wall (SCW) cascade under stress. By contrast, transcription factors and biosynthesis genes for SCW formation were down-regulated, whereas a small set of cellulose synthase-like genes and a huge array of genes involved in cell wall modification were up-regulated in drought-stressed wood. Therefore, we suggest that ABA signaling monitors normal SCW biosynthesis and that drought causes a switch from normal to “stress wood” formation recruiting a dedicated set of genes for cell wall biosynthesis and remodeling. This proposition implies that drought-induced changes in cell wall properties underlie regulatory mechanisms distinct from those of normal wood.

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