scholarly journals Molecular Changes Concomitant with Vascular System Development in Mature Galls Induced by Root-Knot Nematodes in the Model Tree Host Populus tremula × P. alba

2020 ◽  
Vol 21 (2) ◽  
pp. 406 ◽  
Author(s):  
Fabien Baldacci-Cresp ◽  
Marc Behr ◽  
Annegret Kohler ◽  
Nelly Badalato ◽  
Kris Morreel ◽  
...  
Keyword(s):  
Cell Wall ◽  
Secondary Cell Wall ◽  
De Novo ◽  
Vascular System ◽  
System Development ◽  
Primary Cell Wall ◽  
Root Knot Nematode ◽  
Vascular Differentiation ◽  
Vascular Tissues ◽  
Model Tree

One of the most striking features occurring in the root-knot nematode Meloidogyne incognita induced galls is the reorganization of the vascular tissues. During the interaction of the model tree species Populus and M. incognita, a pronounced xylem proliferation was previously described in mature galls. To better characterise changes in expression of genes possibly involved in the induction and the formation of the de novo developed vascular tissues occurring in poplar galls, a comparative transcript profiling of 21-day-old galls versus uninfected root of poplar was performed. Genes coding for transcription factors associated with procambium maintenance and vascular differentiation were shown to be differentially regulated, together with genes partaking in phytohormones biosynthesis and signalling. Specific signatures of transcripts associated to primary cell wall biosynthesis and remodelling, as well as secondary cell wall formation (cellulose, xylan and lignin) were revealed in the galls. Ultimately, we show that molecules derived from the monolignol and salicylic acid pathways and related to secondary cell wall deposition accumulate in mature galls.

scholarly journals The Cell Wall Structure of Xylem Parenchyma

1952 ◽  
Vol 5 (2) ◽  
pp. 223 ◽  
Author(s):  
AB Wardrop ◽  
HE Dadswell
Keyword(s):  
Cell Wall ◽  
Fine Structure ◽  
Secondary Cell Wall ◽  
Primary Cell Wall ◽  
Wall Structure ◽  
Xylem Parenchyma ◽  
Cell Axis ◽  
X Ray ◽  
Ray Methods ◽  
Longitudinal Cell

The fine structure of the cell wall of both ray and vertical parenchyma has been investigated. In all species examined secondary thickening had occurred. In the primary cell wall the micellar orientation was approximately trans"erse to the longitudiJ)aI cell axis. Using optical and X-ray methods the secondary cell wall was shown to possess a helical micellar organization, the micelles being inclined between 30� and 60� to the longitudinal cell axis.

scholarly journals Golgi-localized GALT7 and GALT8 participate in cellulose biosynthesis

2021 ◽  
Author(s):  
Pieter Nibbering ◽  
Romain Castilleux ◽  
Gunnar Wingsle ◽  
Totte Niittylä
Keyword(s):  
Cell Wall ◽  
Golgi Apparatus ◽  
Secondary Cell Wall ◽  
Plant Cell Wall ◽  
Arabinogalactan Protein ◽  
Primary Cell Wall ◽  
Cellulose Content ◽  
Cellulose Biosynthesis ◽  
Cell Wall Assembly ◽  
Protein Levels

AbstractArabinogalactan protein (AGP) glycan biosynthesis in the Golgi apparatus contributes to plant cell wall assembly, but the mechanisms underlying this process are largely unknown. Here, we show that two putative galactosyltransferases -named GALT7 and GALT8 -from the glycosyltransferase family 31 (GT31) of Arabidopsis thaliana participate in cellulose biosynthesis. galt7galt8 mutants show primary cell wall defects manifesting as impaired growth and cell expansion in seedlings and etiolated hypocotyls, along with secondary cell wall defects, apparent as collapsed xylem vessels and reduced xylem wall thickness in the inflorescence stem. These phenotypes were associated with a ∼30% reduction in cellulose content, a ∼50% reduction in secondary cell wall CELLULOSE SYNTHASE (CESA) protein levels and reduced cellulose biosynthesis rate. CESA transcript levels were not significantly altered in galt7galt8 mutants, suggesting that the reduction in CESA levels was caused by a post-transcriptional mechanism. We provide evidence that both GALT7 and GALT8 localise to the Golgi apparatus, while quantitative proteomics experiments revealed reduced levels of the entire FLA subgroup B in the galt7galt8 mutants. This leads us to hypothesize that a defect in FLA subgroup B glycan biosynthesis reduces cellulose biosynthesis rate in galt7galt8 mutants.

Complete substitution of a secondary cell wall with a primary cell wall in Arabidopsis

Nature Plants ◽  
2018 ◽  
Vol 4 (10) ◽  
pp. 777-783 ◽  
Author(s):  
Shingo Sakamoto ◽  
Marc Somssich ◽  
Miyuki T. Nakata ◽  
Faride Unda ◽  
Kimie Atsuzawa ◽  
...  
Keyword(s):  
Cell Wall ◽  
Secondary Cell Wall ◽  
Primary Cell ◽  
Primary Cell Wall

scholarly journals The origin and early evolution of tracheids in vascular plants: integration of palaeobotanical and neobotanical data

2000 ◽  
Vol 355 (1398) ◽  
pp. 857-868 ◽  
Author(s):  
William E. Friedman ◽  
Martha E. Cook
Keyword(s):  
Cell Wall ◽  
Vascular Plants ◽  
Secondary Cell Wall ◽  
Early Evolution ◽  
Land Plants ◽  
Primary Cell Wall ◽  
Wall Structure ◽  
Cell Wall Formation ◽  
Wall Formation ◽  
Resistant Layer

Although there is clear evidence for the establishment of terrestrial plant life by the end of the Ordovician, the fossil record indicates that land plants remained extremely small and structurally simple until the Late Silurian. Among the events associated with this first major radiation of land plants is the evolution of tracheids, complex water–conducting cells defined by the presence of lignified secondary cell wall thickenings. Recent palaeobotanical analyses indicate that Early Devonian tracheids appear to possess secondary cell wall thickenings composed of two distinct layers: a degradation–prone layer adjacent to the primary cell wall and a degradation–resistant (possibly lignified) layer next to the cell lumen. In order to understand better the early evolution of tracheids, developmental and comparative studies of key basal (and potentially plesiomorphic) extant vascular plants have been initiated. Ultra–structural analysis and enzyme degradation studies of wall structure (to approximate diagenetic alterations of fossil tracheid structure) have been conducted on basal members of each of the two major clades of extant vascular plants: Huperzia (Lycophytina) and Equisetum (Euphyllophytina). This research demonstrates that secondary cell walls of extant basal vascular plants include a degradation–prone layer (‘template layer’) and a degradation–resistant layer (‘resistant layer’). This pattern of secondary cell wall formation in the water–conducting cells of extant vascular plants matches the pattern of wall thickenings in the tracheids of early fossil vascular plants and provides a key evolutionary link between tracheids of living vascular plants and those of their earliest fossil ancestors. Further studies of tracheid development and structure among basal extant vascular plants will lead to a more precise reconstruction of the early evolution of water–conducting tissues in land plants, and will add to the current limited knowledge of spatial, temporal and cytochemical aspects of cell wall formation in tracheary elements of vascular plants.

scholarly journals Plastids features and transfer cells occurrence in the phloem of Portulaca mucronata and P. hirsutissima (Portulacaceae)

2014 ◽  
Vol 64 (2) ◽  
pp. 149-153 ◽  
Author(s):  
Maria E. Maranhão Estelita ◽  
Tereza C. Marinho
Keyword(s):  
Cell Wall ◽  
Secondary Cell Wall ◽  
Transfer Cells ◽  
Leaf Structure ◽  
Primary Cell Wall ◽  
Starch Grains ◽  
Kranz Anatomy ◽  
Phloem Parenchyma ◽  
Serra Do Cipó ◽  
Parenchyma Cells

The species of the <em>Portulacaceae</em> of the Serra do Cipó, State of Minas Gerais, Brasil, were studied. In <em>Portulaca mucronata</em> and <em>P. hirsutissima</em> transfer cells are companion and phloem parenchyma cells; they have the same secondary cell wall features, that is, short papillate protuberances which are uniformly distributed around the primary cell wall. These features are similar in both species but they are very distinct from others referred in the literature; this could be useful in Taxonomy. The phloem plastids have a globular protein crystalloid, surrounded by proteinaceous filaments. In <em>P. hirsutissima</em> few starch grains may also be present, and this occurrence is considered primitive in the phylogenetic scale. These features agree with presumptive evolution of those of leaf structure: <em>P. hirsutissima</em> has C<sub>3</sub> photosynthesis structure, and <em>P. mucronata</em> C<sub>4</sub> or Kranz anatomy.

Microscopic Examination Of Vascular Differentiation And Pattern Formation In The Inflorescence Stems Of Arabidopsis

1999 ◽  
Vol 5 (S2) ◽  
pp. 1284-1285
Author(s):  
G. Freshour ◽  
M. Hahn ◽  
Z-H Ye
Keyword(s):  
Pattern Formation ◽  
Vascular Plants ◽  
Vascular System ◽  
The Body ◽  
Vascular Bundles ◽  
Vascular Differentiation ◽  
Evolutionary Mechanisms ◽  
Vascular Tissues ◽  
Inflorescence Stems ◽  
Food Transport

Plant vascular system is the principal means to carry water and food throughout the plant body. It is composed of two types of conducting vascular tissues, xylem and phloem. Xylem carries water and minerals from the root to the shoot, whereas phloem transports photosynthates from leaves to other parts of the body. The evolution of vascular system which solved the problem of water and food transport was considered to be one of the key events for the successful emergence of vascular plants on the land from aquatic environments. Although vascular tissues in almost all vascular plants consist of xylem and phloem, diverse arrangements of vascular tissues within the bundles and of vascular bundles in the stele were evolved (1). The occurrence of diverse vascular patterns in vascular plants offers an excellent opportunity to study the evolutionary mechanisms controlling pattern formation. In this report, we present our studies on the vascular differentiation and pattern formation in the inflorescence stems of Arabidopsis thaliana.

scholarly journals Hexose fluxes, mediated by vacuolar SWEET transporters, are important for xylem development in the inflorescence stem of Arabidopsis thaliana

2020 ◽  
Author(s):  
Emilie Aubry ◽  
Beate Hoffmann ◽  
Françoise Vilaine ◽  
Françoise Gilard ◽  
Patrick A.W. Klemens ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Cell Wall ◽  
Secondary Cell Wall ◽  
Vascular System ◽  
Higher Plants ◽  
Cellular Level ◽  
Xylem Development ◽  
Xylem Cell ◽  
Secondary Cell Wall Synthesis ◽  
Reverse Genetic Approach

ABSTRACTIn higher plants, the development of the vascular system is controlled by a complex network of transcription factors. However, how nutrient availability in the vascular cells affects their development remains to be addressed. At the cellular level, cytosolic sugar availability is regulated mainly by sugar exchanges at the tonoplast through active and/or facilitated transport. In Arabidopsis thaliana, among the tonoplastic transporters, SWEET16 and SWEET17 have been previously localized in the vascular system. Here, using a reverse genetic approach, we propose that sugar exchanges at the tonoplast, mediated by SWEET16, are important for xylem cell division as revealed in particular by the decreased number of xylem cells in the swt16 mutant and the expression of SWEET16 at the procambium-xylem boundary. In addition, we demonstrate that transport of hexoses mediated by SWEET16 and/or SWEET17 is required to sustain the formation of the xylem secondary cell wall. This result is in line with a defect in the xylem cell wall composition as measured by FTIR in the swt16swt17 double mutant and by upregulation of several genes involved in secondary cell wall synthesis. Our work therefore supports a model in which xylem development is partially dependent on the exchange of hexoses at the tonoplast of xylem-forming cells.

scholarly journals Raman imaging of Micrasterias: new insights into shape formation

PROTOPLASMA ◽  
2021 ◽  
Author(s):  
Martin Felhofer ◽  
Konrad Mayr ◽  
Ursula Lütz-Meindl ◽  
Notburga Gierlinger
Keyword(s):  
Cell Wall ◽  
Raman Spectra ◽  
Secondary Cell Wall ◽  
Raman Imaging ◽  
Primary Cell ◽  
Cellulose Microfibrils ◽  
Primary Cell Wall ◽  
Crystalline Cellulose ◽  
Wall Thickening ◽  
Cell Wall Carbohydrates

AbstractThe algae Micrasterias with its star-shaped cell pattern is a perfect unicellular model system to study morphogenesis. How the indentations are formed in the primary cell wall at exactly defined areas puzzled scientists for decades, and they searched for chemical differences in the primary wall of the extending tips compared to the resting indents. We now tackled the question by Raman imaging and scanned in situ Micrasterias cells at different stages of development. Thousands of Raman spectra were acquired from the mother cell and the developing semicell to calculate chemical images based on an algorithm finding the most different Raman spectra. Each of those spectra had characteristic Raman bands, which were assigned to molecular vibrations of BaSO4, proteins, lipids, starch, and plant cell wall carbohydrates. Visualizing the cell wall carbohydrates revealed a cell wall thickening at the indentations of the primary cell wall of the growing semicell and uniplanar orientation of the cellulose microfibrils to the cell surface in the secondary cell wall. Crystalline cellulose dominated in the secondary cell wall spectra, while in the primary cell wall spectra, also xyloglucan and pectin were reflected. Spectral differences between the indent and tip region of the primary cell wall were scarce, but a spectral mixing approach pointed to more cellulose fibrils deposited in the indent region. Therefore, we suggest that cell wall thickening together with a denser network of cellulose microfibrils stiffens the cell wall at the indent and induces different cell wall extensibility to shape the lobes.

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