Overexpression ofgibberellin 20-oxidase1fromPinus densifloraresults in enhanced wood formation with gelatinous fiber development in a transgenic hybrid poplar

Abstract Auxins as phytohormons, responsible for coordination of growing processes, also contribute to the formation of tension wood (TW) in trees, but the mechanism of this process is still unclear. In this study, it has been tried to induce TW formation in erect hybrid poplar trees (in opposite to inclined or bended trees) by treatment with exogenous indole-3-acetic acid (IAA, as one of the auxins) or N-1-naphthylphthalamic acid (NPA) as an auxin transport inhibitor. The treatment with IAA resulted in TW formation and, as expected, NPA treatment did not. The gelatinous fiber formation and higher cellulose content in the cell wall were unambiguous indicators for TW formation. Real-time polymerase chain reaction (PCR) analysis revealed that genes of PIN1, ABCB1, and AUX2 involved in polar auxin transport were highly expressed in trees treated with exogenous IAA. Moreover, expressions of cellulose biosynthesis related genes of UGP1, UGP2 and CesA13 were strongly up-regulated. These observations indicate that the accelerated intercellular polar auxin transport caused by exogenous IAA is accounted for TW formation, i.e. the signal transduction of auxin is affected, which then facilitates cellulose biosynthesis. In contrast, the transcript abundances of PIN1 and all selected cellulose synthases (CesAs) were decreased after NPA treatment via inhibiting the cellular auxin efflux with negative effects on plant’s primary growth. These results are interpreted that TW formation is closely associated with the acceleration of intercellular polar auxin transport.

Download Full-text

Transcriptomic Analysis of Seasonal Gene Expression and Regulation during Xylem Development in “Shanxin” Hybrid Poplar (Populus davidiana × Populus bolleana)

Forests ◽

10.3390/f12040451 ◽

2021 ◽

Vol 12 (4) ◽

pp. 451

Author(s):

Chao Zhao ◽

Youchao He ◽

Ying Yu ◽

Meiqi Zhou ◽

Leifei Zhao ◽

...

Keyword(s):

Cell Wall ◽

Cell Expansion ◽

Hybrid Poplar ◽

Wood Formation ◽

Differentially Expressed ◽

Cell Wall Biosynthesis ◽

Growth Stages ◽

Xylem Development ◽

Go Terms ◽

Different Growth Stages

Xylem development is a key process for wood formation in woody plants. To study the molecular regulatory mechanisms related to xylem development in hybrid poplar P. davidiana × P. bolleana, transcriptome analyses were conducted on developing xylem at six different growth stages within a single growing season. Xylem development and differentially expressed genes in the six time points were selected for a regulatory analysis. Xylem development was observed in stem sections at different growth stages, which showed that xylem development extended from the middle of April to early August and included cell expansion and secondary cell wall biosynthesis. An RNA-seq analysis of six samples with three replicates was performed. After transcriptome assembly and annotation, the differentially expressed genes (DEGs) were identified, and a Gene Ontology (GO) enrichment analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis and expression analysis of the DEGs were performed on each sample. On average, we obtained >20 million clean reads per sample, which were assembled into 84,733 nonredundant transcripts, of which there were 17,603 unigenes with lengths >1 kb. There were 14,890 genes that were differentially expressed among the six stages. The upregulated DEGs were enriched in GO terms related to cell wall biosynthesis between S1 vs. S2 or S3 vs. S4 and, in GO terms, related to phytohormones in the S1 vs. S2 or S4 vs. S5 comparisons. The downregulated DEGs were enriched in GO terms related to cell wall biosynthesis between S4 vs. S5 or S5 vs. S6 and, in GO terms, related to hormones between S1 vs. S2 or S2 vs. S3. The KEGG pathways in the DEGs related to “phenylpropanoid biosynthesis”, “plant hormone signal transduction” and “starch and sucrose metabolism” were significantly enriched among the different stages. The DEGs related to cell expansion, polysaccharide metabolism and synthesis, lignin synthesis, transcription factors and hormones were identified. The identification of genes involved in the regulation of xylem development will increase our understanding of the molecular regulation of wood formation in trees and, also, offers potential targets for genetic manipulation to improve the properties of wood.

Download Full-text

Effects of exogenous 24-epibrassinolide and brassinazole on negative gravitropism and tension wood formation in hybrid poplar (Populus deltoids × Populus nigra)

Planta ◽

10.1007/s00425-018-03074-2 ◽

2019 ◽

Vol 249 (5) ◽

pp. 1449-1463 ◽

Cited By ~ 2

Author(s):

Junlan Gao ◽

Min Yu ◽

Shiliu Zhu ◽

Liang Zhou ◽

Shengquan Liu

Keyword(s):

Tension Wood ◽

Hybrid Poplar ◽

Wood Formation ◽

Populus Nigra ◽

Populus Deltoids ◽

Negative Gravitropism

Download Full-text

Wood Transcriptome Profiling Identifies Critical Pathway Genes of Secondary Wall Biosynthesis and Novel Regulators for Vascular Cambium Development in Populus

Genes ◽

10.3390/genes10090690 ◽

2019 ◽

Vol 10 (9) ◽

pp. 690 ◽

Cited By ~ 1

Author(s):

Min-Ha Kim ◽

Jin-Seong Cho ◽

Hyung-Woo Jeon ◽

Kanidta Sangsawang ◽

Donghwan Shim ◽

...

Keyword(s):

Secondary Wall ◽

Molecular Mechanisms ◽

Developmental Stages ◽

Hybrid Poplar ◽

Secondary Growth ◽

Leaf Tissue ◽

Transcriptome Profiling ◽

Wood Formation ◽

Vascular Cambium ◽

Critical Pathway

Wood, the most abundant biomass on Earth, is composed of secondary xylem differentiated from vascular cambium. However, the underlying molecular mechanisms of wood formation remain largely unclear. To gain insight into wood formation, we performed a series of wood-forming tissue-specific transcriptome analyses from a hybrid poplar (Populus alba × P. glandulosa, clone BH) using RNA-seq. Together with shoot apex and leaf tissue, cambium and xylem tissues were isolated from vertical stem segments representing a gradient of secondary growth developmental stages (i.e., immature, intermediate, and mature stem). In a comparative transcriptome analysis of the ‘developing xylem’ and ‘leaf’ tissue, we could identify critical players catalyzing each biosynthetic step of secondary wall components (e.g., cellulose, xylan, and lignin). Several candidate genes involved in the initiation of vascular cambium formation were found via a co-expression network analysis using abundantly expressed genes in the ‘intermediate stem-derived cambium’ tissue. We found that transgenic Arabidopsis plants overexpressing the PtrHAM4-1, a GRAS family transcription factor, resulted in a significant increase of vascular cambium development. This phenotype was successfully reproduced in the transgenic poplars overexpressing the PtrHAM4-1. Taken together, our results may serve as a springboard for further research to unravel the molecular mechanism of wood formation, one of the most important biological processes on this planet.

Download Full-text

Faculty Opinions recommendation of A transcriptional roadmap to wood formation.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1002595.36105 ◽

2002 ◽

Author(s):

Simon McQueen-Mason

Keyword(s):

Wood Formation

Download Full-text

Faculty Opinions recommendation of A transcriptional roadmap to wood formation.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1002595.29219 ◽

2001 ◽

Author(s):

Klaus Mayer

Keyword(s):

Wood Formation

Download Full-text

Intercropping with Switchgrass Improves Net Greenhouse Gas Balance in Hybrid Poplar Plantations on a Sand Soil

Soil Science Society of America Journal ◽

10.2136/sssaj2017.09.0294 ◽

2017 ◽

Vol 81 (4) ◽

pp. 781

Author(s):

H.P. Collins ◽

P.A. Fay ◽

E. Kimura ◽

S. Fransen ◽

A. Himes

Keyword(s):

Greenhouse Gas ◽

Hybrid Poplar ◽

Sand Soil ◽

Greenhouse Gas Balance ◽

Poplar Plantations ◽

Gas Balance

Download Full-text

Comparison of the Initial Growth of Different Poplar Clones on Four Sites in Western Slovakia—Preliminary Results

BioEnergy Research ◽

10.1007/s12155-020-10227-3 ◽

2021 ◽

Author(s):

Dávid Heilig ◽

Bálint Heil ◽

Christoph Leibing ◽

Heinz Röhle ◽

Gábor Kovács

Keyword(s):

Hybrid Poplar ◽

Aridity Index ◽

Primary Source ◽

Nutrient Status ◽

Physical Parameters ◽

Initial Growth ◽

Key Factors ◽

Groundwater Availability ◽

Secondary Sources ◽

Short Rotation

AbstractThis study was conducted to evaluate four hybrid poplar comparison tests along a groundwater availability gradient in Western Slovakia. The weather fluctuation during the 3-year study period was described with indices, such as the Forestry Aridity Index (FAI) or the hydrothermal coefficient (HTC). The soil chemical and physical parameters were determined from soil samples from the two upper horizons. The nutrient status and supply of the trees were categorized based on leaf elemental analysis. Altogether, 21 different clones from 6 genomic groups were compared. The survival (SRV), diameter at breast height (DBH), and height of the trees (H) had been measured annually since the plantations were established, and from these measurements, mean annual height increment (MAHI) values were derived. These weather, edaphic, and clonal factors were evaluated and compared. Significant effects of the site (edaphic factors) were found as the primary source of variance and clonal differences as secondary sources of variance among the growth of trees. The interaction of site × clone effects was not significant. The results showed that for short rotation forestry (SRF), the site parameters—especially groundwater availability—are key factors.

Download Full-text