| 1. |
- Escamez, Sacha, et al.
(författare)
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A collection of genetically engineered Populus trees reveals wood biomass traits that predict glucose yield from enzymatic hydrolysis
- 2017
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 7:1
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Tidskriftsartikel (refereegranskat)abstract
- Wood represents a promising source of sugars to produce bio-based renewables, including biofuels. However, breaking down lignocellulose requires costly pretreatments because lignocellulose is recalcitrant to enzymatic saccharification. Increasing saccharification potential would greatly contribute to make wood a competitive alternative to petroleum, but this requires improving wood properties. To identify wood biomass traits associated with saccharification, we analyzed a total of 65 traits related to wood chemistry, anatomy and structure, biomass production and saccharification in 40 genetically engineered Populus tree lines. These lines exhibited broad variation in quantitative traits, allowing for multivariate analyses and mathematical modeling. Modeling revealed that seven wood biomass traits associated in a predictive manner with saccharification of glucose after pretreatment. Four of these seven traits were also negatively associated with biomass production, suggesting a trade-off between saccharification potential and total biomass, which has previously been observed to offset the overall sugar yield from whole trees. We therefore estimated the "total-wood glucose yield" (TWG) from whole trees and found 22 biomass traits predictive of TWG after pretreatment. Both saccharification and TWG were associated with low abundant, often overlooked matrix polysaccharides such as arabinose and rhamnose which possibly represent new markers for improved Populus feedstocks.
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| 2. |
- Escamez, Sacha, 1987-, et al.
(författare)
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Cell Death in Cells Overlying Lateral Root Primordia Facilitates Organ Growth in Arabidopsis
- 2020
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Ingår i: Current Biology. - : Elsevier. - 0960-9822 .- 1879-0445. ; 30:3, s. 455-464
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Tidskriftsartikel (refereegranskat)abstract
- Plant organ growth is widely accepted to be determined by cell division and cell expansion, but, unlike that in animals, the contribution of cell elimination has rarely been recognized. We investigated this paradigm during Arabidopsis lateral root formation, when the lateral root primordia (LRP) must traverse three overlying cell layers within the parent root. A subset of LRP-overlying cells displayed the induction of marker genes for cell types undergoing developmental cell death, and their cell death was detected by electron, confocal, and light sheet microscopy techniques. LRP growth was delayed in cell-deathdeficient mutants lacking the positive cell death regulator ORESARA1/ANAC092 (ORE1). LRP growth was restored in ore1-2 knockout plants by genetically inducing cell elimination in cells overlying the LRP or by physically killing LRP-overlying cells by ablation with optical tweezers. Our results support that, in addition to previously discovered mechanisms, cell elimination contributes to regulating lateral root emergence.
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| 3. |
- Escamez, Sacha, et al.
(författare)
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Contribution of cellular autolysis to tissular functions during plant development
- 2017
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Ingår i: Current opinion in plant biology. - : CURRENT BIOLOGY LTD. - 1369-5266 .- 1879-0356. ; 35, s. 124-130
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Forskningsöversikt (refereegranskat)abstract
- Plant development requires specific cells to be eliminated in a predictable and genetically regulated manner referred to as programmed cell death (PCD). However, the target cells do not merely die but they also undergo autolysis to degrade their cellular corpses. Recent progress in understanding developmental cell elimination suggests that distinct proteins execute PCD sensu stricto and autolysis. In addition, cell death alone and cell dismantlement can fulfill different functions. Hence, it appears biologically meaningful to distinguish between the modules of PCD and autolysis during plant development.
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| 4. |
- Escamez, Sacha, 1987-, et al.
(författare)
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Extracellular peptide Kratos restricts cell death during vascular development and stress in Arabidopsis
- 2019
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Ingår i: Journal of Experimental Botany. - : Oxford University Press. - 0022-0957 .- 1460-2431. ; 70:7, s. 2199-2210
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Tidskriftsartikel (refereegranskat)abstract
- During plant vascular development, xylem tracheary elements (TEs) form water-conducting, empty pipes by genetically regulated cell death. Cell death is prevented from spreading to non-TEs by unidentified intercellular mechanisms, downstream of METACASPASE9 (MC9)-mediated regulation of autophagy in TEs. Here, we identified differentially abundant extracellular peptides in vascular-differentiating wild-type and MC9-down-regulated Arabidopsis cell suspensions. A peptide named Kratos rescued the abnormally high ectopic non-TE death resulting from either MC9 knockout or TE-specific overexpression of the ATG5 autophagy protein during experimentally induced vascular differentiation in Arabidopsis cotyledons. Kratos also reduced cell death following mechanical damage and extracellular ROS production in Arabidopsis leaves. Stress-induced but not vascular non-TE cell death was enhanced by another identified peptide, named Bia. Bia is therefore reminiscent of several known plant cell death-inducing peptides acting as damage-associated molecular patterns. In contrast, Kratos plays a novel extracellular cell survival role in the context of development and during stress response.
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| 5. |
- Escamez, Sacha, 1987-, et al.
(författare)
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Fluorescence Lifetime Imaging as an in Situ and Label-Free Readout for the Chemical Composition of Lignin
- 2021
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Ingår i: ACS Sustainable Chemistry and Engineering. - : American Chemical Society. - 2168-0485. ; 9:51
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Tidskriftsartikel (refereegranskat)abstract
- Naturally fluorescent polymeric molecules such as collagen, resilin, cutin, suberin, or lignin can serve as renewable sources of bioproducts. Theoretical physics predicts that the fluorescence lifetime of these polymers is related to their chemical composition. We verified this prediction for lignin, a major structural element in plant cell walls that form woody biomass. Lignin is composed of different phenylpropanoid units, and its composition affects its properties, biological functions, and the utilization of wood biomass. We carried out fluorescence lifetime imaging microscopy (FLIM) measurements of wood cell wall lignin in a population of 90 hybrid aspen trees genetically engineered to display differences in cell wall chemistry and structure. We also measured the wood cell wall composition by classical analytical methods in these trees. Using statistical modeling and machine learning algorithms, we identified parameters of fluorescence lifetime that predict the content of S-type and G-type lignin units, the two main types of units in the lignin of angiosperm (flowering) plants. In a first step toward tailoring lignin biosynthesis toward improvement of woody biomass feedstocks, we show how FLIM can reveal the dynamics of lignin biosynthesis in two different biological contexts, including in vivo while lignin is being synthesized in the walls of living cells. © 2021 The Authors.
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| 6. |
- Escamez, Sacha, 1987-, et al.
(författare)
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Genetic markers and tree properties predicting wood biorefining potential in aspen (Populus tremula) bioenergy feedstock
- 2023
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Ingår i: Biotechnology for Biofuels and Bioproducts. - : BioMed Central Ltd. - 2731-3654. ; 16:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Wood represents the majority of the biomass on land and constitutes a renewable source of biofuels and other bioproducts. However, wood is recalcitrant to bioconversion, raising a need for feedstock improvement in production of, for instance, biofuels. We investigated the properties of wood that affect bioconversion, as well as the underlying genetics, to help identify superior tree feedstocks for biorefining. Results: We recorded 65 wood-related and growth traits in a population of 113 natural aspen genotypes from Sweden (https://doi.org/10.5061/dryad.gtht76hrd). These traits included three growth and field performance traits, 20 traits for wood chemical composition, 17 traits for wood anatomy and structure, and 25 wood saccharification traits as indicators of bioconversion potential. Glucose release after saccharification with acidic pretreatment correlated positively with tree stem height and diameter and the carbohydrate content of the wood, and negatively with the content of lignin and the hemicellulose sugar units. Most of these traits displayed extensive natural variation within the aspen population and high broad-sense heritability, supporting their potential in genetic improvement of feedstocks towards improved bioconversion. Finally, a genome-wide association study (GWAS) revealed 13 genetic loci for saccharification yield (on a whole-tree-biomass basis), with six of them intersecting with associations for either height or stem diameter of the trees. Conclusions: The simple growth traits of stem height and diameter were identified as good predictors of wood saccharification yield in aspen trees. GWAS elucidated the underlying genetics, revealing putative genetic markers for bioconversion of bioenergy tree feedstocks. © 2023, The Author(s).
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| 7. |
- Escamez, Sacha, 1987-, et al.
(författare)
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METACASPASE9 modulates autophagy to confine cell death tothe target cells during Arabidopsis vascular xylem differentiation
- 2016
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Ingår i: Biology Open. - : The Company of Biologists ltd. - 2046-6390. ; 5:2, s. 122-129
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Tidskriftsartikel (refereegranskat)abstract
- We uncovered that the level of autophagy in plant cells undergoingprogrammed cell death determines the fate of the surrounding cells.Our approach consisted of using Arabidopsis thaliana cell culturescapable of differentiating into two different cell types: vasculartracheary elements (TEs) that undergo programmed cell death(PCD) and protoplast autolysis, and parenchymatic non-TEs thatremain alive. The TE cell type displayed higher levels of autophagywhen expression of the TE-specific METACASPASE9 (MC9) wasreduced using RNAi (MC9-RNAi). Misregulation of autophagy in theMC9-RNAi TEs coincided with ectopic death of the non-TEs, implyingthe existence of an autophagy-dependent intercellular signallingfrom within the TEs towards the non-TEs. Viability of the non-TEswas restored when AUTOPHAGY2 (ATG2) was downregulatedspecifically in MC9-RNAi TEs, demonstrating the importance ofautophagy in the spatial confinement of cell death. Our resultssuggest that other eukaryotic cells undergoing PCD might also needto tightly regulate their level of autophagy to avoid detrimentalconsequences for the surrounding cells.
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| 8. |
- Escamez, Sacha, et al.
(författare)
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Programmes of cell death and autolysis in tracheary elements : when a suicidal cell arranges its own corpse removal
- 2014
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Ingår i: Journal of Experimental Botany. - : Oxford University Press. - 0022-0957 .- 1460-2431. ; 65:5, s. 1313-1321
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Forskningsöversikt (refereegranskat)abstract
- Differentiation of tracheary elements (TEs) is finalized by programmed cell death (PCD) and autolysis. This review integrates TE differentiation, PCD, and autolysis in a biological and evolutionary context.Tracheary element (TE) differentiation represents a unique system to study plant developmental programmed cell death (PCD). TE PCD occurs after deposition of the secondary cell walls when an unknown signal induces tonoplast rupture and the arrest of cytoplasmic streaming. TE PCD is tightly followed by autolysis of the protoplast and partial hydrolysis of the primary cell walls. This review integrates TE differentiation, programmed cell death (PCD), and autolysis in a biological and evolutionary context. The collective evidence from the evolutionary and molecular studies suggests that TE differentiation consists primarily of a programme for cell death and autolysis under the direct control of the transcriptional master switches VASCULAR NAC DOMAIN 6 (VND6) and VND7. In this scenario, secondary cell walls represent a later innovation to improve the water transport capacity of TEs which necessitates transcriptional regulators downstream of VND6 and VND7. One of the most fascinating features of TEs is that they need to prepare their own corpse removal by expression and accumulation of hydrolases that are released from the vacuole after TE cell death. Therefore, TE differentiation involves, in addition to PCD, a programmed autolysis which is initiated before cell death and executed post-mortem. It has recently become clear that TE PCD and autolysis are separate processes with separate molecular regulation. Therefore, the importance of distinguishing between the cell death programme per se and autolysis in all plant PCD research and of careful description of the morphological, biochemical, and molecular sequences in each of these processes, is advocated.
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| 9. |
- Escamez, Sacha, 1987-, et al.
(författare)
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Quick histochemical staining methods to detect cell death in xylem elements of plant tissues
- 2017. - 1
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Ingår i: Xylem. - New York : Humana Press. - 9781493967209 - 9781493967223 ; , s. 27-36
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Bokkapitel (refereegranskat)abstract
- Histochemical assays of xylem cell death cannot take advantage of the conventional methods for detection of cell death, such as staining with propidium iodide or trypan/Evans blue or the TUNEL staining. This chapter presents two alternative histochemical methods that can be used to detect xylem cell death quickly and reliably using light microscopy. The first method is a viability stain that can be used to detect cell death of different types of xylem elements in basically any plant species. The second method reveals cell death in xylem vessel elements based on their functionality in transport of water and small water-soluble stains.
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| 10. |
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| 11. |
- Escamez, Sacha, 1987-
(författare)
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Xylem cells cooperate in the control of lignification and cell death during plant vascular development
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The evolutionary success of land plants was fostered by the acquisition of the xylem vascular tissue which conducts water and minerals upwards from the roots. The xylem tissue of flowering plants is composed of three main types of cells: the sap-conducting tracheary elements (TE), the fibres which provide mechanical support and the parenchyma cells which provide metabolic support to the tissue. Both the TEs and the fibres deposit thick polysaccharidic secondary cell walls (SCWs), reinforced by a rigid phenolic polymer called lignin. The cell walls of TEs form efficient water conducting hollow tubes after the TEs have undergone programmed cell death (PCD) and complete protoplast degradation as a part of their differentiation. The work presented in this thesis studied the regulation of TE PCD by characterizing the function of the candidate PCD regulator METACASPASE 9 (MC9) in Arabidopsis thaliana xylogenic cell suspensions. These cell suspensions can be externally induced to differentiate into a mix of TEs and parenchymatic non-TE cells, thus representing an ideal system to study the cellular processes of TE PCD. In this system, TEs with reduced expression of MC9 were shown to have increased levels of autophagy and to trigger the ectopic death of the non-TE cells. The viability of the non-TE cells could be restored by down-regulating autophagy specifically in the TEs with reduced MC9 expression. Therefore, this work showed that MC9 must tightly regulate the level of autophagy during TE PCD in order to prevent the TEs from becoming harmful to the non-TEs. Hence, this work demonstrated the existence of a cellular cooperation between the TEs and the surrounding parenchymatic cells during TE PCD. The potential cooperation between the TEs and the neighbouring parenchyma during the biosynthesis of lignin was also investigated. The cupin domain containing protein PIRIN2 was found to regulate TE lignification in a non-cell autonomous manner in Arabidopsis thaliana. More precisely, PIRIN2 was shown to function as an antagonist of positive transcriptional regulators of lignin biosynthetic genes in xylem parenchyma cells. Part of the transcriptional regulation by PIRIN2 involves chromatin modifications, which represent a new type of regulation of lignin biosynthesis. Because xylem constitutes the wood in tree species, this newly discovered regulation of non-cell autonomous lignification represents a potential target to modify lignin biosynthesis in order to overcome the recalcitrance of the woody biomass for the production of biofuels.
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| 12. |
- Gandla, Madhavi Latha, et al.
(författare)
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Overexpression of vesicle-associated membrane protein PttVAP27-17 as a tool to improve biomass production and the overall saccharification yields in Populus trees
- 2021
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Ingår i: Biotechnology for Biofuels. - : Springer Science and Business Media LLC. - 1754-6834. ; 14:1
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Tidskriftsartikel (refereegranskat)abstract
- Background Bioconversion of wood into bioproducts and biofuels is hindered by the recalcitrance of woody raw material to bioprocesses such as enzymatic saccharification. Targeted modification of the chemical composition of the feedstock can improve saccharification but this gain is often abrogated by concomitant reduction in tree growth. Results In this study, we report on transgenic hybrid aspen (Populus tremula x tremuloides) lines that showed potential to increase biomass production both in the greenhouse and after 5 years of growth in the field. The transgenic lines carried an overexpression construct for Populus tremula x tremuloides vesicle-associated membrane protein (VAMP)-associated protein PttVAP27-17 that was selected from a gene-mining program for novel regulators of wood formation. Analytical-scale enzymatic saccharification without any pretreatment revealed for all greenhouse-grown transgenic lines, compared to the wild type, a 20-44% increase in the glucose yield per dry weight after enzymatic saccharification, even though it was statistically significant only for one line. The glucose yield after enzymatic saccharification with a prior hydrothermal pretreatment step with sulfuric acid was not increased in the greenhouse-grown transgenic trees on a dry-weight basis, but increased by 26-50% when calculated on a whole biomass basis in comparison to the wild-type control. Tendencies to increased glucose yields by up to 24% were present on a whole tree biomass basis after acidic pretreatment and enzymatic saccharification also in the transgenic trees grown for 5 years on the field when compared to the wild-type control. Conclusions The results demonstrate the usefulness of gene-mining programs to identify novel genes with the potential to improve biofuel production in tree biotechnology programs. Furthermore, multi-omic analyses, including transcriptomic, proteomic and metabolomic analyses, performed here provide a toolbox for future studies on the function of VAP27 proteins in plants.
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| 13. |
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| 14. |
- Lakehal, Abdellah, et al.
(författare)
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ETHYLENE RESPONSE FACTOR 115 integrates jasmonate and cytokinin signaling machineries to repress adventitious rooting in Arabidopsis
- 2020
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Ingår i: New Phytologist. - : Wiley-Blackwell Publishing Inc.. - 0028-646X .- 1469-8137. ; 228, s. 1611-1626
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Tidskriftsartikel (refereegranskat)abstract
- Adventitious root initiation (ARI) is ade novoorganogenesis program and a key adaptive trait in plants. Several hormones regulate ARI but the underlying genetic architecture that integrates the hormonal crosstalk governing this process remains largely elusive. In this study, we use genetics, genome editing, transcriptomics, hormone profiling and cell biological approaches to demonstrate a crucial role played by the APETALA2/ETHYLENE RESPONSE FACTOR 115 transcription factor. We demonstrate that ERF115 functions as a repressor of ARI by activating the cytokinin (CK) signaling machinery. We also demonstrate thatERF115is transcriptionally activated by jasmonate (JA), an oxylipin-derived phytohormone, which represses ARI in NINJA-dependent and independent manners. Our data indicate that NINJA-dependent JA signaling in pericycle cells blocks early events of ARI. Altogether, our results reveal a previously unreported molecular network involving cooperative crosstalk between JA and CK machineries that represses ARI.
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| 15. |
- Menard, Delphine, et al.
(författare)
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Life beyond death : the formation of xylem sap conduits
- 2015
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Ingår i: Plant programmed cell death. - Cham : Springer. - 9783319210339 - 9783319210322 - 9783319352015 ; , s. 55-76
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Bokkapitel (refereegranskat)abstract
- Xylem is the vascular tissue conducting water and minerals in plants. The conduction of the hydro-mineral sap in this tissue is enabled by specific conduit cells named tracheary elements (TEs). These vascular cells undergo a distinct differentiation programme which requires programmed cell death (PCD) to functionalise the cell for sap conduction: PCD empties the cell lumen leaving a hollow corpse delimited only by its cell wall to form the future vascular cylinder. In contrast to many other cell types, PCD initiates the 'physiological life' of TEs to enable the cell to conduct the hydro-mineral sap. This central role of PCD appeared as the first distinct differentiation event of TE ancestor cells during plant evolution. Breakthrough studies combining real-time live-cell imaging and TE differentiation in cell suspension cultures enabled to define the temporal succession of the pre-mortem TE differentiation events - cellulose and hemicellulose depositions in the secondary cell wall - and the post-mortem events including cell wall lignification and the clearing of the residual protoplast. The coordination between these different events and the exact timing of PCD is controlled by specific signalling molecules.
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| 16. |
- Pesquet, Edouard, et al.
(författare)
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Non-Cell-Autonomous Postmortem Lignification of Tracheary Elements in Zinnia elegans
- 2013
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Ingår i: The Plant Cell. - : American Society of Plant Biologists. - 1040-4651 .- 1532-298X. ; 25:4, s. 1314-1328
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Tidskriftsartikel (refereegranskat)abstract
- Postmortem lignification of xylem tracheary elements (TEs) has been debated for decades. Here, we provide evidence in Zinnia elegans TE cell cultures, using pharmacological inhibitors and in intact Z. elegans plants using Fourier transform infrared microspectroscopy, that TE lignification occurs postmortem (i.e., after TE programmed cell death). In situ RT-PCR verified expression of the lignin monomer biosynthetic cinnamoyl CoA reductase and cinnamyl alcohol dehydrogenase in not only the lignifying TEs but also in the unlignified non-TE cells of Z. elegans TE cell cultures and in living, parenchymatic xylem cells that surround TEs in stems. These cells were also shown to have the capacity to synthesize and transport lignin monomers and reactive oxygen species to the cell walls of dead TEs. Differential gene expression analysis in Z. elegans TE cell cultures and concomitant functional analysis in Arabidopsis thaliana resulted in identification of several genes that were expressed in the non-TE cells and that affected lignin chemistry on the basis of pyrolysis-gas chromatography/mass spectrometry analysis. These data suggest that living, parenchymatic xylem cells contribute to TE lignification in a non-cellautonomous manner, thus enabling the postmortem lignification of TEs.
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| 17. |
- Salojarvi, Jarkko, et al.
(författare)
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Genome sequencing and population genomic analyses provide insights into the adaptive landscape of silver birch
- 2017
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Ingår i: Nature Genetics. - : NATURE PUBLISHING GROUP. - 1061-4036 .- 1546-1718. ; 49:6, s. 904-912
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Tidskriftsartikel (refereegranskat)abstract
- Silver birch (Betula pendula) is a pioneer boreal tree that can be induced to flower within 1 year. Its rapid life cycle, small (440-Mb) genome, and advanced germplasm resources make birch an attractive model for forest biotechnology. We assembled and chromosomally anchored the nuclear genome of an inbred B. pendula individual. Gene duplicates from the paleohexaploid event were enriched for transcriptional regulation, whereas tandem duplicates were overrepresented by environmental responses. Population resequencing of 80 individuals showed effective population size crashes at major points of climatic upheaval. Selective sweeps were enriched among polyploid duplicates encoding key developmental and physiological triggering functions, suggesting that local adaptation has tuned the timing of and cross-talk between fundamental plant processes. Variation around the tightly-linked light response genes PHYC and FRS10 correlated with latitude and longitude and temperature, and with precipitation for PHYC. Similar associations characterized the growth-promoting cytokinin response regulator ARR1, and the wood development genes KAK and MED5A.
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| 18. |
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| 19. |
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| 20. |
- Wessels, Bernard, 1985-, et al.
(författare)
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An AP2/ERF transcription factor ERF139 coordinates xylem cell expansion and secondary cell wall deposition
- 2019
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Ingår i: New Phytologist. - : Wiley-Blackwell. - 0028-646X .- 1469-8137. ; 224:4, s. 1585-1599
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Tidskriftsartikel (refereegranskat)abstract
- Differentiation of xylem elements involves cell expansion, secondary cell wall (SCW) deposition and programmed cell death. Transitions between these phases require strict spatiotemporal control.The function of Populus ERF139 (Potri.013G101100) in xylem differentiation was characterized in transgenic overexpression and dominant repressor lines of ERF139 in hybrid aspen (Populus tremula × tremuloides). Xylem properties, SCW chemistry and downstream targets were analyzed in both types of transgenic trees using microscopy techniques, Fourier transform‐infrared spectroscopy, pyrolysis‐GC/MS, wet chemistry methods and RNA sequencing.Opposite phenotypes were observed in the secondary xylem vessel sizes and SCW chemistry in the two different types of transgenic trees, supporting the function of ERF139 in suppressing the radial expansion of vessel elements and stimulating accumulation of guaiacyl‐type lignin and possibly also xylan. Comparative transcriptomics identified genes related to SCW biosynthesis (LAC5, LBD15, MYB86) and salt and drought stress‐responsive genes (ANAC002, ABA1) as potential direct targets of ERF139.The phenotypes of the transgenic trees and the stem expression profiles of ERF139potential target genes support the role of ERF139 as a transcriptional regulator of xylem cell expansion and SCW formation, possibly in response to osmotic changes of the cells.
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| 21. |
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| 22. |
- Zhang, Bo, et al.
(författare)
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PIRIN2 suppresses S-type lignin accumulation in a noncell-autonomous manner in Arabidopsis xylem elements
- 2020
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Ingår i: New Phytologist. - : New Phytologist Trust. - 0028-646X .- 1469-8137. ; 225:5, s. 1923-1935
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Tidskriftsartikel (refereegranskat)abstract
- PIRIN (PRN) genes encode cupin domain‐containing proteins that function as transcriptional co‐regulators in humans but that are poorly described in plants. A previous study in xylogenic cell cultures of Zinnia elegans suggested a role for a PRN protein in lignification. This study aimed to identify the function of Arabidopsis (Arabidopsis thaliana) PRN proteins in lignification of xylem tissues.Chemical composition of the secondary cell walls was analysed in Arabidopsis stems and/or hypocotyls by pyrolysis–gas chromatography/mass spectrometry, 2D‐nuclear magnetic resonance and phenolic profiling. Secondary cell walls of individual xylem elements were chemotyped by Fourier transform infrared and Raman microspectroscopy.Arabidopsis PRN2 suppressed accumulation of S‐type lignin in Arabidopsis stems and hypocotyls. PRN2 promoter activity and PRN2:GFP fusion protein were localised specifically in cells next to the vessel elements, suggesting a role for PRN2 in noncell‐autonomous lignification of xylem vessels. Accordingly, PRN2 modulated lignin chemistry in the secondary cell walls of the neighbouring vessel elements.These results indicate that PRN2 suppresses S‐type lignin accumulation in the neighbourhood of xylem vessels to bestow G‐type enriched lignin composition on the secondary cell walls of the vessel elements. Gene expression analyses suggested that PRN2 function is mediated by regulation of the expression of the lignin‐biosynthetic genes.
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| 23. |
- Zhang, Bo, et al.
(författare)
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The chromatin-modifying protein HUB2 is involved in the regulation of lignin composition in xylem vessels
- 2020
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Ingår i: Journal of Experimental Botany. - : Oxford University Press. - 0022-0957 .- 1460-2431. ; 71:18, s. 5484-5494
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Tidskriftsartikel (refereegranskat)abstract
- PIRIN2 (PRN2) was earlier reported to suppress syringyl (S)-type lignin accumulation of xylem vessels of Arabidopsis thaliana. In the present study, we report yeast two-hybrid results supporting the interaction of PRN2 with HISTONE MONOUBIQUITINATION2 (HUB2) in Arabidopsis. HUB2 has been previously implicated in several plant developmental processes, but not in lignification. Interaction between PRN2 and HUB2 was verified by β-galactosidase enzymatic and co-immunoprecipitation assays. HUB2 promoted the deposition of S-type lignin in the secondary cell walls of both stem and hypocotyl tissues, as analysed by pyrolysis-GC/MS. Chemical fingerprinting of individual xylem vessel cell walls by Raman and Fourier transform infrared microspectroscopy supported the function of HUB2 in lignin deposition. These results, together with a genetic analysis of the hub2 prn2 double mutant, support the antagonistic function of PRN2 and HUB2 in deposition of S-type lignin. Transcriptome analyses indicated the opposite regulation of the S-type lignin biosynthetic gene FERULATE-5-HYDROXYLASE1 by PRN2 and HUB2 as the underlying mechanism. PRN2 and HUB2 promoter activities co-localized in cells neighbouring the xylem vessel elements, suggesting that the S-type lignin-promoting function of HUB2 is antagonized by PRN2 for the benefit of the guaiacyl (G)-type lignin enrichment of the neighbouring xylem vessel elements.
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