Alicja Banasiak - Profile on Academia.edu (original) (raw)

Papers by Alicja Banasiak

Research paper thumbnail of Organ Patterning at the Shoot Apical Meristem (SAM): The Potential Role of the Vascular System

Organ Patterning at the Shoot Apical Meristem (SAM): The Potential Role of the Vascular System

Symmetry, Jan 30, 2023

Research paper thumbnail of Influence of PIN1 gene mutation on the pattern of primary vasculature in Arabidopsis inflorescence shoot

Influence of PIN1 gene mutation on the pattern of primary vasculature in Arabidopsis inflorescence shoot

Polish Journal of Natural Sciences. Supplement, 2003

Research paper thumbnail of Auxin conjugated to fluorescent dyes - a tool for the analysis of auxin transport pathways

Auxin conjugated to fluorescent dyes - a tool for the analysis of auxin transport pathways

Plant Biology, 2014

Auxin is a small molecule involved in most processes related to plant growth and development. Its... more Auxin is a small molecule involved in most processes related to plant growth and development. Its effect usually depends on the distribution in tissues and the formation of concentration gradients. Until now there has been no tool for the direct tracking of auxin transport at the cellular and tissue level; therefore the majority of studies have been based on various indirect methods. However, due to their various restrictions, relatively little is known about the relationship between various pathways of auxin transport and specific developmental processes. We present a new research tool: fluorescently labelled auxin in the form of a conjugate with two different fluorescent tracers, FITC and RITC, which allows direct observation of auxin transport in plant tissues. Chemical analysis and biological tests have shown that our conjugates have auxin-like biological activity and transport; therefore they can be used in all experimental systems as an alternative to IAA. In addition, the conjugates are a universal tool that can be applied in studies of all plant groups and species. The conjugation procedure presented in this paper can be adapted to other fluorescent dyes, which are constantly being improved. In our opinion, the conjugates greatly expand the possibilities of research concerning the role of auxin and its transport in different developmental processes in plants.

Research paper thumbnail of Functional study of a PL1 family gene expressed during xylem cell differentiation in hybrid aspen

Functional study of a PL1 family gene expressed during xylem cell differentiation in hybrid aspen

Research paper thumbnail of Xyloglucan endo-transglycosylase (XET) functions in gelatinous layers of tension wood fibers in poplar: a glimpse into the mechanism of the balancing act of trees. Plant Cell Physiol. 48, 843–855. doi: 10.1093/pcp/pcm055

Tension wood is a specialized tissue of deciduous trees that functions in bending woody stems to ... more Tension wood is a specialized tissue of deciduous trees that functions in bending woody stems to optimize their position in space. Tension wood fibers that develop on one side of the stem have an increased potency to shrink compared with fibers on the opposite side, thus creating a bending moment. It is believed that the gelatinous (G) cell wall layer containing almost pure cellulose of tension wood fibers is pivotal to their shrinking. By analyzing saccharide composi-tion and linkage in isolated G-layers of poplar, we found that they contain some matrix components in addition to cellulose, of which xyloglucan is the most abundant. Xyloglucan, xyloglucan endo-transglycosylase (XET) activity and xylo-glucan endo-transglycosylase/hydrolase (XTH) gene products were detected in developing G-layers by labeling using CCRC-M1 monoclonal antibody, in situ incorporation

Research paper thumbnail of Anatomical and developmental consequences of the delay in protoxylem differentiation in Arabidopsis mutant pin1

Anatomical and developmental consequences of the delay in protoxylem differentiation in Arabidopsis mutant pin1

Research paper thumbnail of Expression of aspen homologue of KORRIGAN1, PttCel9A1, affects cellulose crystallinity in secondary growth

Expression of aspen homologue of KORRIGAN1, PttCel9A1, affects cellulose crystallinity in secondary growth

Cellulose in particular and wood in general are valuable biomaterials for humanity, and cellulose... more Cellulose in particular and wood in general are valuable biomaterials for humanity, and cellulose is now also in the spotlight as a starting material for the production of biofuel. Understanding the processes of wood formation and cellulose biosynthesis could therefore be rewarding, and genomics and proteomics approaches have been initiated to learn more about wood biology. For example, the genome of the tree Populus trichocarpa has been completed during 2006. A single-gene approach then has to follow, to elucidate specific patterns and enzymatic details. This thesis depicts how a gene encoding a membrane-anchored cellulase was isolated from Populus tremula x tremuloides Mich, how the corresponding protein was expressed in heterologous hosts, purified and characterized by substrate analysis using different techniques. The in vivo function and modularity of the membrane-anchored cellulase was also addressed using overexpression and complementation analysis in Arabidopsis thaliana. Am...

Research paper thumbnail of Aspen Tension Wood Fibers Contain b-(1→4)-Galactans and Acidic Arabinogalactans Retained by Cellulose Microfibrils in

Aspen Tension Wood Fibers Contain b-(1→4)-Galactans and Acidic Arabinogalactans Retained by Cellulose Microfibrils in

Research paper thumbnail of Polarny transport auksyny - hipotezy i odkrycia

Polarny transport auksyny - hipotezy i odkrycia

Postepy Biologii Komorki, 2003

Research paper thumbnail of Elongation of wood fibers combines features of diffuse and tip growth

Elongation of wood fibers combines features of diffuse and tip growth

New Phytologist

Research paper thumbnail of A sustained CYCLINB1;1 and STM expression in the neoplastic tissues induced by Rhodococcus fascians on Arabidopsis underlies the persistence of the leafy gall structure

A sustained CYCLINB1;1 and STM expression in the neoplastic tissues induced by Rhodococcus fascians on Arabidopsis underlies the persistence of the leafy gall structure

Plant Signaling & Behavior

Research paper thumbnail of Structural Integrity of Vascular System in Branching Units of Coniferous Shoot

Acta Societatis Botanicorum Poloniae

In conifers with spiral phyllotaxis, two numbers: one of the vascular sympodia and the second of ... more In conifers with spiral phyllotaxis, two numbers: one of the vascular sympodia and the second of cortical resin canals, define the shoot anatomic diameter. This in turn reflects the size and vigor of the apical meristem. Both numbers belong to the mathematical series, associated with the shoot phyllotactic pattern. The number of canals is one step lower in a series than the number of sympodia. The first one, easier to determine, automatically defines the second. Using this protocol and screening the large number of branching shoots of selected conifers, we have discovered strong correlation between orientation of vascular sympodia in the lateral and supporting branches. There was no such correlation with regard to the chiral configurations of phyllotaxis. This finding reveals the presence of special phyllotactic compensation in the case of differences in anatomic diameter of the parental and lateral shoot under the imperative of maintaining the sympodia orientation within one branch...

Research paper thumbnail of Arabidopsis XTH4 and XTH9 contribute to wood cell expansion and secondary wall formation

Plant Physiology

Xyloglucan is the major hemicellulose of dicotyledon primary cell walls, affecting the load-beari... more Xyloglucan is the major hemicellulose of dicotyledon primary cell walls, affecting the load-bearing framework with the participation of xyloglucan endo-transglycosylase/hydrolases (XTHs). We used loss-and gain-of function approaches to study functions of XTH4 and XTH9 abundantly expressed in cambial regions during secondary growth of Arabidopsis (Arabidopsis thaliana). In secondarily thickened hypocotyls, these enzymes had positive effects on vessel element expansion and fiber intrusive growth. They also stimulated secondary wall thickening but reduced secondary xylem production. Cell wall analyses of inflorescence stems revealed changes in lignin, cellulose, and matrix sugar composition indicating an overall increase in secondary versus primary walls in mutants, indicative of higher xylem production compared with the wild type (since secondary walls were thinner). Intriguingly, the number of secondary cell wall layers compared with the wild type was increased in xth9 and reduced in xth4, whereas the double mutant xth4x9 displayed an intermediate number of layers. These changes correlated with specific Raman signals from the walls, indicating changes in lignin and cellulose. Secondary walls were affected also in the interfascicular fibers, where neither XTH4 nor XTH9 was expressed, indicating that these effects were indirect. Transcripts involved in secondary wall biosynthesis and cell wall integrity sensing, including THESEUS1 and WALL ASSOCIATED KINASE2, were highly induced in the mutants, indicating that deficiency in XTH4 and XTH9 triggers cell wall integrity signaling, which, we propose, stimulates xylem cell production and modulates secondary wall thickening. Prominent effects of XTH4 and XTH9 on secondary xylem support the hypothesis that altered xyloglucan affects wood properties both directly and via cell wall integrity sensing.

Research paper thumbnail of Arabidopsis XTH4 and XTH9 contribute to wood cell expansion and secondary wall formation

ABSTRACTIn dicotyledons, xyloglucan is the major hemicellulose of primary walls affecting the loa... more ABSTRACTIn dicotyledons, xyloglucan is the major hemicellulose of primary walls affecting the load-bearing framework with participation of XTH enzymes. We used loss- and gain-of function approaches to study functions of abundant cambial region expressed XTH4 and XTH9 in secondary growth. In secondarily thickened hypocotyls, these enzymes had positive effects on vessel element expansion and fiber intrusive growth. In addition, they stimulated secondary wall thickening, but reduced secondary xylem production. Cell wall analyses of inflorescence stems revealed changes in lignin, cellulose, and matrix sugar composition, indicating overall increase in secondary versus primary walls in the mutants, indicative of higher xylem production compared to wild type (since secondary walls were thinner). Intriguingly, the number of secondary cell wall layers was increased in xth9 and reduced in xth4, whereas the double mutant xth4x9 displayed intermediate number of layers. These changes correlated ...

Research paper thumbnail of Ontogenetic Changes in Auxin Biosynthesis and Distribution Determine the Organogenic Activity of the Shoot Apical Meristem in pin1 Mutants

International Journal of Molecular Sciences

In the shoot apical meristem (SAM) of Arabidopsis, PIN1-dependent polar auxin transport (PAT) reg... more In the shoot apical meristem (SAM) of Arabidopsis, PIN1-dependent polar auxin transport (PAT) regulates two crucial developmental processes: organogenesis and vascular system formation. However, the knockout mutation in the PIN1 gene does not fully inhibit these two processes. Therefore, we investigated a potential source of auxin for organogenesis and vascularization during inflorescence stem development. We analyzed auxin distribution in wild-type (WT) and pin1 mutant plants using a refined protocol of auxin immunolocalization; auxin activity, with the response reporter pDR5:GFP; and expression of auxin biosynthesis genes YUC1 and YUC4. Our results revealed that regardless of the functionality of PIN1-mediated PAT, auxin is present in the SAM and vascular strands. In WT plants, auxin always accumulates in all cells of the SAM, whereas in pin1 mutants, its localization within the SAM changes ontogenetically and is related to changes in the structure of the vascular system, organoge...

Research paper thumbnail of Auxin-mediated regulation of vascular patterning in Arabidopsis thaliana leaves

Plant Cell Reports

The vascular system develops in response to auxin flow as continuous strands of conducting tissue... more The vascular system develops in response to auxin flow as continuous strands of conducting tissues arranged in regular spatial patterns. However, a mechanism governing their regular and repetitive formation remains to be fully elucidated. A model system for studying the vascular pattern formation is the process of leaf vascularization in Arabidopsis. In this paper, we present current knowledge of important factors and their interactions in this process. Additionally, we propose the sequence of events leading to the emergence of continuous vascular strands and point to significant problems that need to be resolved in the future to gain a better understanding of the regulation of the vascular pattern development. Arabidopsis • Polar auxin transport • Leaf • Vascular system • Venation pattern • PIN Communicated by Neal Stewart.

Research paper thumbnail of Neovascularization during leafy gall formation on Arabidopsis thaliana upon Rhodococcus fascians infection

Neovascularization during leafy gall formation on Arabidopsis thaliana upon Rhodococcus fascians infection

Planta

Research paper thumbnail of Diversity of phyllotaxis in land plants in reference to the shoot apical meristem structure

Acta Societatis Botanicorum Poloniae, 2016

Regularity and periodicity in the arrangements of organs in all groups of land plants raise quest... more Regularity and periodicity in the arrangements of organs in all groups of land plants raise questions about the mechanisms underlying phyllotactic pattern formation. The initiation of the lateral organs (leaves, flowers, etc.), and thus, their spatio-temporal positioning, occurs in the shoot apical meristem (SAM) and is related to the structure and organogenic activity of the meristem. In this review, we present some aspects of the diversity and stability of phyllotactic patterns in the major lineages of land plants, from bryophytes to angiosperms, in which SAM structures differ significantly. In addition, we discuss some of the possible mechanisms involved in the formation of the recurring arrangement of the lateral organs.

Research paper thumbnail of Aspen tension wood fibers contain β-(1→4)-galactans and acidic arabinogalactans retained by cellulose microfibrils in gelatinous walls

Plant Physiology, 2015

Contractile cell walls are found in various plant organs and tissues such as tendrils, contractil... more Contractile cell walls are found in various plant organs and tissues such as tendrils, contractile roots, and tension wood. The tension-generating mechanism is not known but is thought to involve special cell wall architecture. We previously postulated that tension could result from the entrapment of certain matrix polymers within cellulose microfibrils. As reported here, this hypothesis was corroborated by sequential extraction and analysis of cell wall polymers that are retained by cellulose microfibrils in tension wood and normal wood of hybrid aspen (Populus tremula 3 Populus tremuloides). b-(1→4)-Galactan and type II arabinogalactan were the main large matrix polymers retained by cellulose microfibrils that were specifically found in tension wood. Xyloglucan was detected mostly in oligomeric form in the alkali-labile fraction and was enriched in tension wood. b-(1→4)-Galactan and rhamnogalacturonan I backbone epitopes were localized in the gelatinous cell wall layer. Type II arabinogalactans retained by cellulose microfibrils had a higher content of (methyl)glucuronic acid and galactose in tension wood than in normal wood. Thus, b-(1→4)-galactan and a specialized form of type II arabinogalactan are trapped by cellulose microfibrils specifically in tension wood and, thus, are the main candidate polymers for the generation of tensional stresses by the entrapment mechanism. We also found high b-galactosidase activity accompanying tension wood differentiation and propose a testable hypothesis that such activity might regulate galactan entrapment and, thus, mechanical properties of cell walls in tension wood.

Research paper thumbnail of Glycoside Hydrolase Activities in Cell Walls of Sclerenchyma Cells in the Inflorescence Stems of Arabidopsis thaliana Visualized in Situ

Plants, 2014

Techniques for in situ localization of gene products provide indispensable information for unders... more Techniques for in situ localization of gene products provide indispensable information for understanding biological function. In the case of enzymes, biological function is directly related to activity, and therefore, knowledge of activity patterns is central to understanding the molecular controls of plant development. We have previously developed a novel type of fluorogenic substrate for revealing glycoside hydrolase activity in planta, based on resorufin β-glycosides Here, we explore a wider range of such substrates to visualize glycoside hydrolase activities in Arabidopsis inflorescence stems in real time, especially highlighting distinct distribution patterns of these activities in the secondary cell walls of Plants 2014, 3 514 sclerenchyma cells. The results demonstrate that β-1,4-glucosidase, β-1,4-glucanase and β-1,4-galactosidase activities accompany secondary wall deposition. In contrast, xyloglucanase activity follows a different pattern, with the highest signal observed in mature cells, concentrated in the middle lamella. These data further the understanding of the process of cell wall deposition and function in sclerenchymatic tissues of plants.

Research paper thumbnail of Organ Patterning at the Shoot Apical Meristem (SAM): The Potential Role of the Vascular System

Organ Patterning at the Shoot Apical Meristem (SAM): The Potential Role of the Vascular System

Symmetry, Jan 30, 2023

Research paper thumbnail of Influence of PIN1 gene mutation on the pattern of primary vasculature in Arabidopsis inflorescence shoot

Influence of PIN1 gene mutation on the pattern of primary vasculature in Arabidopsis inflorescence shoot

Polish Journal of Natural Sciences. Supplement, 2003

Research paper thumbnail of Auxin conjugated to fluorescent dyes - a tool for the analysis of auxin transport pathways

Auxin conjugated to fluorescent dyes - a tool for the analysis of auxin transport pathways

Plant Biology, 2014

Auxin is a small molecule involved in most processes related to plant growth and development. Its... more Auxin is a small molecule involved in most processes related to plant growth and development. Its effect usually depends on the distribution in tissues and the formation of concentration gradients. Until now there has been no tool for the direct tracking of auxin transport at the cellular and tissue level; therefore the majority of studies have been based on various indirect methods. However, due to their various restrictions, relatively little is known about the relationship between various pathways of auxin transport and specific developmental processes. We present a new research tool: fluorescently labelled auxin in the form of a conjugate with two different fluorescent tracers, FITC and RITC, which allows direct observation of auxin transport in plant tissues. Chemical analysis and biological tests have shown that our conjugates have auxin-like biological activity and transport; therefore they can be used in all experimental systems as an alternative to IAA. In addition, the conjugates are a universal tool that can be applied in studies of all plant groups and species. The conjugation procedure presented in this paper can be adapted to other fluorescent dyes, which are constantly being improved. In our opinion, the conjugates greatly expand the possibilities of research concerning the role of auxin and its transport in different developmental processes in plants.

Research paper thumbnail of Functional study of a PL1 family gene expressed during xylem cell differentiation in hybrid aspen

Functional study of a PL1 family gene expressed during xylem cell differentiation in hybrid aspen

Research paper thumbnail of Xyloglucan endo-transglycosylase (XET) functions in gelatinous layers of tension wood fibers in poplar: a glimpse into the mechanism of the balancing act of trees. Plant Cell Physiol. 48, 843–855. doi: 10.1093/pcp/pcm055

Tension wood is a specialized tissue of deciduous trees that functions in bending woody stems to ... more Tension wood is a specialized tissue of deciduous trees that functions in bending woody stems to optimize their position in space. Tension wood fibers that develop on one side of the stem have an increased potency to shrink compared with fibers on the opposite side, thus creating a bending moment. It is believed that the gelatinous (G) cell wall layer containing almost pure cellulose of tension wood fibers is pivotal to their shrinking. By analyzing saccharide composi-tion and linkage in isolated G-layers of poplar, we found that they contain some matrix components in addition to cellulose, of which xyloglucan is the most abundant. Xyloglucan, xyloglucan endo-transglycosylase (XET) activity and xylo-glucan endo-transglycosylase/hydrolase (XTH) gene products were detected in developing G-layers by labeling using CCRC-M1 monoclonal antibody, in situ incorporation

Research paper thumbnail of Anatomical and developmental consequences of the delay in protoxylem differentiation in Arabidopsis mutant pin1

Anatomical and developmental consequences of the delay in protoxylem differentiation in Arabidopsis mutant pin1

Research paper thumbnail of Expression of aspen homologue of KORRIGAN1, PttCel9A1, affects cellulose crystallinity in secondary growth

Expression of aspen homologue of KORRIGAN1, PttCel9A1, affects cellulose crystallinity in secondary growth

Cellulose in particular and wood in general are valuable biomaterials for humanity, and cellulose... more Cellulose in particular and wood in general are valuable biomaterials for humanity, and cellulose is now also in the spotlight as a starting material for the production of biofuel. Understanding the processes of wood formation and cellulose biosynthesis could therefore be rewarding, and genomics and proteomics approaches have been initiated to learn more about wood biology. For example, the genome of the tree Populus trichocarpa has been completed during 2006. A single-gene approach then has to follow, to elucidate specific patterns and enzymatic details. This thesis depicts how a gene encoding a membrane-anchored cellulase was isolated from Populus tremula x tremuloides Mich, how the corresponding protein was expressed in heterologous hosts, purified and characterized by substrate analysis using different techniques. The in vivo function and modularity of the membrane-anchored cellulase was also addressed using overexpression and complementation analysis in Arabidopsis thaliana. Am...

Research paper thumbnail of Aspen Tension Wood Fibers Contain b-(1→4)-Galactans and Acidic Arabinogalactans Retained by Cellulose Microfibrils in

Aspen Tension Wood Fibers Contain b-(1→4)-Galactans and Acidic Arabinogalactans Retained by Cellulose Microfibrils in

Research paper thumbnail of Polarny transport auksyny - hipotezy i odkrycia

Polarny transport auksyny - hipotezy i odkrycia

Postepy Biologii Komorki, 2003

Research paper thumbnail of Elongation of wood fibers combines features of diffuse and tip growth

Elongation of wood fibers combines features of diffuse and tip growth

New Phytologist

Research paper thumbnail of A sustained CYCLINB1;1 and STM expression in the neoplastic tissues induced by Rhodococcus fascians on Arabidopsis underlies the persistence of the leafy gall structure

A sustained CYCLINB1;1 and STM expression in the neoplastic tissues induced by Rhodococcus fascians on Arabidopsis underlies the persistence of the leafy gall structure

Plant Signaling & Behavior

Research paper thumbnail of Structural Integrity of Vascular System in Branching Units of Coniferous Shoot

Acta Societatis Botanicorum Poloniae

In conifers with spiral phyllotaxis, two numbers: one of the vascular sympodia and the second of ... more In conifers with spiral phyllotaxis, two numbers: one of the vascular sympodia and the second of cortical resin canals, define the shoot anatomic diameter. This in turn reflects the size and vigor of the apical meristem. Both numbers belong to the mathematical series, associated with the shoot phyllotactic pattern. The number of canals is one step lower in a series than the number of sympodia. The first one, easier to determine, automatically defines the second. Using this protocol and screening the large number of branching shoots of selected conifers, we have discovered strong correlation between orientation of vascular sympodia in the lateral and supporting branches. There was no such correlation with regard to the chiral configurations of phyllotaxis. This finding reveals the presence of special phyllotactic compensation in the case of differences in anatomic diameter of the parental and lateral shoot under the imperative of maintaining the sympodia orientation within one branch...

Research paper thumbnail of Arabidopsis XTH4 and XTH9 contribute to wood cell expansion and secondary wall formation

Plant Physiology

Xyloglucan is the major hemicellulose of dicotyledon primary cell walls, affecting the load-beari... more Xyloglucan is the major hemicellulose of dicotyledon primary cell walls, affecting the load-bearing framework with the participation of xyloglucan endo-transglycosylase/hydrolases (XTHs). We used loss-and gain-of function approaches to study functions of XTH4 and XTH9 abundantly expressed in cambial regions during secondary growth of Arabidopsis (Arabidopsis thaliana). In secondarily thickened hypocotyls, these enzymes had positive effects on vessel element expansion and fiber intrusive growth. They also stimulated secondary wall thickening but reduced secondary xylem production. Cell wall analyses of inflorescence stems revealed changes in lignin, cellulose, and matrix sugar composition indicating an overall increase in secondary versus primary walls in mutants, indicative of higher xylem production compared with the wild type (since secondary walls were thinner). Intriguingly, the number of secondary cell wall layers compared with the wild type was increased in xth9 and reduced in xth4, whereas the double mutant xth4x9 displayed an intermediate number of layers. These changes correlated with specific Raman signals from the walls, indicating changes in lignin and cellulose. Secondary walls were affected also in the interfascicular fibers, where neither XTH4 nor XTH9 was expressed, indicating that these effects were indirect. Transcripts involved in secondary wall biosynthesis and cell wall integrity sensing, including THESEUS1 and WALL ASSOCIATED KINASE2, were highly induced in the mutants, indicating that deficiency in XTH4 and XTH9 triggers cell wall integrity signaling, which, we propose, stimulates xylem cell production and modulates secondary wall thickening. Prominent effects of XTH4 and XTH9 on secondary xylem support the hypothesis that altered xyloglucan affects wood properties both directly and via cell wall integrity sensing.

Research paper thumbnail of Arabidopsis XTH4 and XTH9 contribute to wood cell expansion and secondary wall formation

ABSTRACTIn dicotyledons, xyloglucan is the major hemicellulose of primary walls affecting the loa... more ABSTRACTIn dicotyledons, xyloglucan is the major hemicellulose of primary walls affecting the load-bearing framework with participation of XTH enzymes. We used loss- and gain-of function approaches to study functions of abundant cambial region expressed XTH4 and XTH9 in secondary growth. In secondarily thickened hypocotyls, these enzymes had positive effects on vessel element expansion and fiber intrusive growth. In addition, they stimulated secondary wall thickening, but reduced secondary xylem production. Cell wall analyses of inflorescence stems revealed changes in lignin, cellulose, and matrix sugar composition, indicating overall increase in secondary versus primary walls in the mutants, indicative of higher xylem production compared to wild type (since secondary walls were thinner). Intriguingly, the number of secondary cell wall layers was increased in xth9 and reduced in xth4, whereas the double mutant xth4x9 displayed intermediate number of layers. These changes correlated ...

Research paper thumbnail of Ontogenetic Changes in Auxin Biosynthesis and Distribution Determine the Organogenic Activity of the Shoot Apical Meristem in pin1 Mutants

International Journal of Molecular Sciences

In the shoot apical meristem (SAM) of Arabidopsis, PIN1-dependent polar auxin transport (PAT) reg... more In the shoot apical meristem (SAM) of Arabidopsis, PIN1-dependent polar auxin transport (PAT) regulates two crucial developmental processes: organogenesis and vascular system formation. However, the knockout mutation in the PIN1 gene does not fully inhibit these two processes. Therefore, we investigated a potential source of auxin for organogenesis and vascularization during inflorescence stem development. We analyzed auxin distribution in wild-type (WT) and pin1 mutant plants using a refined protocol of auxin immunolocalization; auxin activity, with the response reporter pDR5:GFP; and expression of auxin biosynthesis genes YUC1 and YUC4. Our results revealed that regardless of the functionality of PIN1-mediated PAT, auxin is present in the SAM and vascular strands. In WT plants, auxin always accumulates in all cells of the SAM, whereas in pin1 mutants, its localization within the SAM changes ontogenetically and is related to changes in the structure of the vascular system, organoge...

Research paper thumbnail of Auxin-mediated regulation of vascular patterning in Arabidopsis thaliana leaves

Plant Cell Reports

The vascular system develops in response to auxin flow as continuous strands of conducting tissue... more The vascular system develops in response to auxin flow as continuous strands of conducting tissues arranged in regular spatial patterns. However, a mechanism governing their regular and repetitive formation remains to be fully elucidated. A model system for studying the vascular pattern formation is the process of leaf vascularization in Arabidopsis. In this paper, we present current knowledge of important factors and their interactions in this process. Additionally, we propose the sequence of events leading to the emergence of continuous vascular strands and point to significant problems that need to be resolved in the future to gain a better understanding of the regulation of the vascular pattern development. Arabidopsis • Polar auxin transport • Leaf • Vascular system • Venation pattern • PIN Communicated by Neal Stewart.

Research paper thumbnail of Neovascularization during leafy gall formation on Arabidopsis thaliana upon Rhodococcus fascians infection

Neovascularization during leafy gall formation on Arabidopsis thaliana upon Rhodococcus fascians infection

Planta

Research paper thumbnail of Diversity of phyllotaxis in land plants in reference to the shoot apical meristem structure

Acta Societatis Botanicorum Poloniae, 2016

Regularity and periodicity in the arrangements of organs in all groups of land plants raise quest... more Regularity and periodicity in the arrangements of organs in all groups of land plants raise questions about the mechanisms underlying phyllotactic pattern formation. The initiation of the lateral organs (leaves, flowers, etc.), and thus, their spatio-temporal positioning, occurs in the shoot apical meristem (SAM) and is related to the structure and organogenic activity of the meristem. In this review, we present some aspects of the diversity and stability of phyllotactic patterns in the major lineages of land plants, from bryophytes to angiosperms, in which SAM structures differ significantly. In addition, we discuss some of the possible mechanisms involved in the formation of the recurring arrangement of the lateral organs.

Research paper thumbnail of Aspen tension wood fibers contain β-(1→4)-galactans and acidic arabinogalactans retained by cellulose microfibrils in gelatinous walls

Plant Physiology, 2015

Contractile cell walls are found in various plant organs and tissues such as tendrils, contractil... more Contractile cell walls are found in various plant organs and tissues such as tendrils, contractile roots, and tension wood. The tension-generating mechanism is not known but is thought to involve special cell wall architecture. We previously postulated that tension could result from the entrapment of certain matrix polymers within cellulose microfibrils. As reported here, this hypothesis was corroborated by sequential extraction and analysis of cell wall polymers that are retained by cellulose microfibrils in tension wood and normal wood of hybrid aspen (Populus tremula 3 Populus tremuloides). b-(1→4)-Galactan and type II arabinogalactan were the main large matrix polymers retained by cellulose microfibrils that were specifically found in tension wood. Xyloglucan was detected mostly in oligomeric form in the alkali-labile fraction and was enriched in tension wood. b-(1→4)-Galactan and rhamnogalacturonan I backbone epitopes were localized in the gelatinous cell wall layer. Type II arabinogalactans retained by cellulose microfibrils had a higher content of (methyl)glucuronic acid and galactose in tension wood than in normal wood. Thus, b-(1→4)-galactan and a specialized form of type II arabinogalactan are trapped by cellulose microfibrils specifically in tension wood and, thus, are the main candidate polymers for the generation of tensional stresses by the entrapment mechanism. We also found high b-galactosidase activity accompanying tension wood differentiation and propose a testable hypothesis that such activity might regulate galactan entrapment and, thus, mechanical properties of cell walls in tension wood.

Research paper thumbnail of Glycoside Hydrolase Activities in Cell Walls of Sclerenchyma Cells in the Inflorescence Stems of Arabidopsis thaliana Visualized in Situ

Plants, 2014

Techniques for in situ localization of gene products provide indispensable information for unders... more Techniques for in situ localization of gene products provide indispensable information for understanding biological function. In the case of enzymes, biological function is directly related to activity, and therefore, knowledge of activity patterns is central to understanding the molecular controls of plant development. We have previously developed a novel type of fluorogenic substrate for revealing glycoside hydrolase activity in planta, based on resorufin β-glycosides Here, we explore a wider range of such substrates to visualize glycoside hydrolase activities in Arabidopsis inflorescence stems in real time, especially highlighting distinct distribution patterns of these activities in the secondary cell walls of Plants 2014, 3 514 sclerenchyma cells. The results demonstrate that β-1,4-glucosidase, β-1,4-glucanase and β-1,4-galactosidase activities accompany secondary wall deposition. In contrast, xyloglucanase activity follows a different pattern, with the highest signal observed in mature cells, concentrated in the middle lamella. These data further the understanding of the process of cell wall deposition and function in sclerenchymatic tissues of plants.