Cell Wall Maturation of Arabidopsis Trichomes Is Dependent on Exocyst Subunit EXO70H4 and Involves Callose Deposition

Callose, B-1,3-glucan, a component of cell walls, is associated with phloem sieve plates, plasmodesmata, and other cell wall structures that are formed in response to wounding or infection. Callose reacts with aniline blue to form a fluorescent complex that can be recognized in the light microscope with ultraviolet illumination. We have identified callose in cell wall protuberances that are formed spontaneously in suspension-cultured cells of S. tortuosus and in the tips of root hairs formed in sterile callus cultures of S. tortuosus. Callose deposits in root hairs are restricted to root hair tips which appear to be damaged or deformed, while normal root hair tips lack callose deposits. The callose deposits found in suspension culture cells are restricted to regions where unusual outgrowths or protuberances are formed on the cell surfaces, specifically regions that are the sites of new cell wall formation.Callose formation has been shown to be regulated by intracellular calcium levels.

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Dicer-like proteins influence Arabidopsis root microbiota independent of RNA-directed DNA methylation

Microbiome ◽

10.1186/s40168-020-00966-y ◽

2021 ◽

Vol 9 (1) ◽

Author(s):

Richa Kaushal ◽

Li Peng ◽

Sunil K. Singh ◽

Mengrui Zhang ◽

Xinlian Zhang ◽

...

Keyword(s):

Dna Methylation ◽

Cell Wall ◽

Plant Defense ◽

Root Exudates ◽

Rrna Gene ◽

Epigenetic Factors ◽

Callose Deposition ◽

Arabidopsis Root ◽

Triple Mutation ◽

Root Microbiota

Abstract Background Plants are naturally associated with root microbiota, which are microbial communities influential to host fitness. Thus, it is important to understand how plants control root microbiota. Epigenetic factors regulate the readouts of genetic information and consequently many essential biological processes. However, it has been elusive whether RNA-directed DNA methylation (RdDM) affects root microbiota assembly. Results By applying 16S rRNA gene sequencing, we investigated root microbiota of Arabidopsis mutants defective in the canonical RdDM pathway, including dcl234 that harbors triple mutation in the Dicer-like proteins DCL3, DCL2, and DCL4, which produce small RNAs for RdDM. Alpha diversity analysis showed reductions in microbe richness from the soil to roots, reflecting the selectivity of plants on root-associated bacteria. The dcl234 triple mutation significantly decreases the levels of Aeromonadaceae and Pseudomonadaceae, while it increases the abundance of many other bacteria families in the root microbiota. However, mutants of the other examined key players in the canonical RdDM pathway showed similar microbiota as Col-0, indicating that the DCL proteins affect root microbiota in an RdDM-independent manner. Subsequently gene analysis by shotgun sequencing of root microbiome indicated a selective pressure on microbial resistance to plant defense in the dcl234 mutant. Consistent with the altered plant-microbe interactions, dcl234 displayed altered characters, including the mRNA and sRNA transcriptomes that jointly highlighted altered cell wall organization and up-regulated defense, the decreased cellulose and callose deposition in root xylem, and the restructured profile of root exudates that supported the alterations in gene expression and cell wall modifications. Conclusion Our findings demonstrate an important role of the DCL proteins in influencing root microbiota through integrated regulation of plant defense, cell wall compositions, and root exudates. Our results also demonstrate that the canonical RdDM is dispensable for Arabidopsis root microbiota. These findings not only establish a connection between root microbiota and plant epigenetic factors but also highlight the complexity of plant regulation of root microbiota.

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First person – Destiny Davis

Journal of Cell Science ◽

10.1242/jcs.254649 ◽

2020 ◽

Vol 133 (19) ◽

pp. jcs254649

Keyword(s):

Cell Wall ◽

Plant Cell ◽

Early Career ◽

University Of California ◽

First Person ◽

Unicellular Alga ◽

Callose Deposition ◽

Early Career Researchers ◽

Selection Of

ABSTRACTFirst Person is a series of interviews with the first authors of a selection of papers published in Journal of Cell Science, helping early-career researchers promote themselves alongside their papers. Destiny Davis is first author on ‘Callose deposition is essential for the completion of cytokinesis in the unicellular alga Penium margaritaceum’, published in JCS. Destiny conducted the research described in this article while a PhD student in Georgia Drakakaki's lab at University of California, Davis, CA, USA. She is now a postdoc in the lab of Jenny Mortimer at the Joint BioEnergy Institute (JBEI), Emeryville, CA, USA, where she is endlessly fascinated by the inner workings of the plant cell related to the cell wall.

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The Importance of the Enzyme Sucrose Synthase for Cell Wall Synthesis in Plants

10.32747/1994.7568771.bard ◽

1994 ◽

Author(s):

Deborah P. Delmer ◽

Prem S. Chourey

Keyword(s):

Cell Wall ◽

Plasma Membrane ◽

Cotton Seed ◽

Sucrose Synthase ◽

Starch Synthesis ◽

Endosperm Development ◽

Current Evidence ◽

Cell Wall Synthesis ◽

Maize Endosperm ◽

Callose Deposition

The goal of this work was to understand the role of the enzyme sucrose synthase (SuSy) in synthesis of cellulose and callose in plants. The work resulting from the this grant leads to a number of conclusions. SuSy clearly plays diverse roles in carbon metabolism. It can associate with the plasma membrane of cells undergoing rapid cellulose deposition, such as cotton fibers, developing maize endosperm, gravistimulated pulvini, and transfer cells of the cotton seed. It is also concentrated at sites of high callose deposition (tapetal cells; cell plates). When SuSy levels are lowered by mutation or by anti-sense technology, cell walls undergo degeneration (maize endosperm) and show reduced levels of cellulose (potato tubers). In sum, our evidence has very much strengthened the concept that SuSy does function in the plasma membrane to channel carbon from sucrose via UDP-glucose to glucan synthase complexes. Soluble SuSy also clearly plays a role in providing carbon for starch synthesis and respiration. Surprisingly, we found that the cotton seed is one unique case where SuSy apparently does not play a role in starch synthesis. Current evidence in sum suggests that no specific SuSy gene encodes the membrane-associated form, although in maize the SS 1 form of SuSy may be most important for cell wall synthesis in the early stages of endosperm development. Work is still in progress to determine what does control membrane localization - and the current evidence we have favors a role for Ca2+, and possibly also protein phosphorylation by differentially regulated protein kinases. Finally, we have discovered for the first time, a major new family of genes that encode the catalytic subunit of the cellulose synthase of plants - a result that has been widely cited and opens many new approaches for the study of this important plant function.

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Lemon maturation causes anatomical and biochemical changes at the flavedo tissue level

Botany ◽

10.1139/cjb-2021-0121 ◽

2021 ◽

Author(s):

Patricia L. Albornoz ◽

Roque Interdonato ◽

Ariadna Hammann ◽

Mariana Rosa ◽

Fernando E. Prado ◽

...

Keyword(s):

Cell Wall ◽

Agricultural Practices ◽

Tissue Level ◽

Sucrose Content ◽

Harvest Management ◽

Callose Deposition ◽

Transport Pathways ◽

Transcellular Transport ◽

Symplastic Pathway ◽

High Enzymatic Activity

Plants mobilize the photosynthates by three transport pathways: apoplastic, symplastic through plasmodesmata (PD), and transcellular. In flavedo of postharvest mature lemons, a high activity of cell wall-bound invertase (WI), an enzyme associated with transcellular transport of monosaccharides, has been detected. In order to elucidate whether this high enzymatic activity is related to restricted transport in the symplastic pathway with fruit maturation, the aim of the present work was to compare anatomical and biochemical parameters in peel tissues of immature and mature lemons. Anatomical structure focusing on cell walls, callose deposition, WI activity, and sucrose content were analyzed in peel tissues of immature and mature lemons. The parenchyma of flavedo tissue of immature lemons presented an elevated number of primary pit fields (PPF). These PPF, associated to PD or cell wall interruptions, had the appearance of a string of beads. However, in mature lemons, the number of PPF was scarce due to callose deposition. WI activity and apoplastic sucrose content increased significantly in flavedo of mature lemons in comparison to immature lemons. Present findings lay structural and functional bases relevant to understand differences between immature and mature lemons, which would help to design agricultural practices in pre- and post-harvest management.

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Callose deposition is essential for the completion of cytokinesis in the unicellular alga Penium margaritaceum

Journal of Cell Science ◽

10.1242/jcs.249599 ◽

2020 ◽

Vol 133 (19) ◽

pp. jcs249599 ◽

Cited By ~ 1

Author(s):

Destiny J. Davis ◽

Minmin Wang ◽

Iben Sørensen ◽

Jocelyn K. C. Rose ◽

David S. Domozych ◽

...

Keyword(s):

Cell Wall ◽

Cell Plate ◽

Molecular Evidence ◽

Callose Deposition ◽

Division Plane ◽

Unicellular Algae ◽

A Cell ◽

Division Cell ◽

Wall Assembly ◽

Cell Wall Deposition

ABSTRACTCytokinesis in land plants involves the formation of a cell plate that develops into the new cell wall. Callose, a β-1,3 glucan, accumulates at later stages of cell plate development, presumably to stabilize this delicate membrane network during expansion. Cytokinetic callose is considered specific to multicellular plant species, because it has not been detected in unicellular algae. Here we present callose at the cytokinesis junction of the unicellular charophyte, Penium margaritaceum. Callose deposition at the division plane of P. margaritaceum showed distinct, spatiotemporal patterns likely representing distinct roles of this polymer in cytokinesis. Pharmacological inhibition of callose deposition by endosidin 7 resulted in cytokinesis defects, consistent with the essential role for this polymer in P. margaritaceum cell division. Cell wall deposition at the isthmus zone was also affected by the absence of callose, demonstrating the dynamic nature of new wall assembly in P. margaritaceum. The identification of candidate callose synthase genes provides molecular evidence for callose biosynthesis in P. margaritaceum. The evolutionary implications of cytokinetic callose in this unicellular zygnematopycean alga is discussed in the context of the conquest of land by plants.This article has an associated First Person interview with the first author of the paper.

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Cytochemistry of defense responses in cassava infected by Xanthomonas campestris pv. manihotis

Canadian Journal of Microbiology ◽

10.1139/m96-145 ◽

1996 ◽

Vol 42 (11) ◽

pp. 1131-1143 ◽

Cited By ~ 56

Author(s):

K. Kpémoua ◽

B. Boher ◽

M. Nicole ◽

P. Calatayud ◽

J. P. Geiger

Keyword(s):

Cell Wall ◽

Bacterial Growth ◽

Xanthomonas Campestris ◽

Secondary Cell Wall ◽

Defense Responses ◽

Resistant Variety ◽

Xylem Parenchyma ◽

Callose Deposition ◽

Wide Range ◽

Parenchyma Cells

Stems of susceptible and resistant cassava plants have been cytologically investigated for their defense reactions to an aggressive strain of Xanthomonas campestris pv. manihotis. Histochemistry, in conjunction with gold cytochemistry, revealed that in susceptible and resistant plants, phloem and xylem parenchyma cells displayed a wide range of responses that limited the bacterial growth within the infected plants. Lignification and suberization associated with callose deposition were effective mechanisms that reinforced host barriers in the phloem. In the infected xylem, vessels were plugged by a material of pectic and (or) lignin-like origin. Flavonoids have been seen to be incorporated in secondary cell wall coatings. These reactions occurred at a higher intensity in the resistant plants. The number of phoem and xylem cells producing autofluorescent compounds was higher in infected resistant plants than in susceptible plants. Reactions have been observed in the resistant variety only, such as secretion of phenol-like molecules by tyloses and hyperplasic activity of phloem cells that compartmentalized bacterial lysis pockets, which are potent secondary inoculum sources.Key words: lignin, suberin, callose, phenol, tylose, flavonoid, pectin.

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Panama Disease: Cell Wall Reinforcement in Banana Roots in Response to Elicitors from Fusarium oxysporum f. sp. cubense Race Four

Phytopathology ◽

10.1094/phyto.2000.90.10.1173 ◽

2000 ◽

Vol 90 (10) ◽

pp. 1173-1180 ◽

Cited By ~ 63

Author(s):

Ana R. D. C. F. De Ascensao ◽

Ian A. Dubery

Keyword(s):

Cell Wall ◽

Fusarium Oxysporum ◽

Defense Mechanism ◽

Cinnamyl Alcohol Dehydrogenase ◽

Defense Responses ◽

Early Screening ◽

Callose Deposition ◽

Breeding Programs ◽

Biochemical Basis ◽

Panama Disease

The biochemical basis of tolerance in banana to Fusarium wilt, caused by the pathogen Fusarium oxysporum f. sp. cubense race four, was investigated. Tissue culture banana plants from tolerant cv. Goldfinger and susceptible cv. Williams were maintained in a hydroponic system and inoculated with conidial suspensions to evaluate the degree of tolerance to susceptibility between the two clones and to investigate the effectiveness of this technique as a potential tool for early screening for resistance in breeding programs. Similarly, defense responses were induced by treatment of the plants with an elicitor preparation from the mycelial cell walls of the pathogen. Differences in the induction of lignin and callose deposition, phenolics, and the enzymes involved in cell wall strengthening; phenylalanine ammonia lyase, cinnamyl alcohol dehydrogenase, peroxidase, and polyphenol oxidase were determined. Root tissue of the tolerant cv. Goldfinger responded to the fungal elicitor through the strong deposition of lignin, preceded by the induction or activation of the enzyme activities involved in the synthesis and polymerization thereof, whereas only slight increases were observed for the susceptible cv. Williams. No increase in callose content was observed for either clone. These results indicate an important role for cell wall strengthening due to the deposition of lignin as an inducible defense mechanism of banana roots against F. oxysporum f. sp. cubense race four.

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Callose deposition is essential for the completion of cytokinesis in the unicellular alga, Penium margaritaceum

10.1101/2020.05.28.122580 ◽

2020 ◽

Author(s):

Destiny J. Davis ◽

Minmin Wang ◽

Iben Sørensen ◽

Jocelyn K.C. Rose ◽

David S. Domozych ◽

...

Keyword(s):

Cell Wall ◽

Cell Plate ◽

Molecular Evidence ◽

Callose Deposition ◽

Division Plane ◽

Cell Wall Assembly ◽

Unicellular Algae ◽

A Cell ◽

Division Cell ◽

Wall Assembly

AbstractCytokinesis in land plants involves the formation of a cell plate that develops into the new cell wall. Callose is a β-1,3 glucan that transiently accumulates at later stages of cell plate development and is thought to stabilize the delicate membrane network of the cell plate as it expands. Cytokinetic callose deposition is currently considered specific to multicellular plant species as it has not been detected in unicellular algae. Here we present callose at the cytokinesis junction of the unicellular charophyte, Penium margaritaceum. Notably, callose deposition at the division plane of P. margaritaceum showed distinct, spatiotemporal patterns that could represent distinct roles of this polymer in cytokinesis and cell wall assembly. Pharmacological inhibition of cytokinetic callose deposition by Endosidin 7 treatment resulted in cytokinesis defects, consistent with the essential role for this polymer in P. margaritaceum cell division. Cell wall deposition and assembly at the isthmus zone was also affected by the absence of callose, demonstrating the dynamic nature of new wall assembly in P. margaritaceum. The identification of candidate callose synthase genes provides molecular evidence for callose biosynthesis in P. margaritaceum. The evolutionary implications of cytokinetic callose in this unicellular Zygnematopycean alga is discussed in the context of the conquest of land by plants.Summary StatementEvolutionarily conserved callose in Penium margaritaceum is essential for the completion of cytokinesis.

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Biochemical and Cytological Interactions Between Callose Synthase and Microtubules in the Tobacco Pollen Tube

10.21203/rs.3.rs-1082515/v1 ◽

2021 ◽

Author(s):

LUIGI PARROTTA ◽

Claudia Faleri ◽

Cecilia Del Casino ◽

Lavinia Mareri ◽

Iris Aloisi ◽

...

Keyword(s):

Cell Wall ◽

Pollen Tube ◽

Membrane Microdomains ◽

Homogeneous Distribution ◽

Cell Wall Polysaccharide ◽

Cell Wall Polysaccharides ◽

Callose Synthase ◽

Callose Deposition ◽

Biotic Stresses ◽

Transport Vesicles

Abstract Callose is a cell wall polysaccharide involved in several fundamental biological processes, ranging from plant development to response to abiotic and biotic stresses. To understand how callose deposition is regulated, it is important to know how its synthesizing enzyme, i.e., callose synthase, is regulated and if it interacts with vesicular-cytoskeletal system of plant cells. Actin filaments are thought to determine the long-range distribution of callose synthase through transport vesicles. Unlike other enzymes (such as cellulose synthase) that synthesize cell wall polysaccharides, the spatial and biochemical relationships between callose synthase and microtubules are poorly understood. Some experimental evidence already support the association between callose synthase and tubulin, however, despite its importance in maintaining plant integrity, knowledge about regulation of callose biosynthesis is still limited. Here we investigated the association between callose synthase and cytoskeleton by biochemical and ultrastructural analyses in a model system, pollen tube, where callose is an essential cell wall component. Native 2-D electrophoresis and isolation of the callose synthase complex confirmed that callose synthase is associated with tubulin and can interface with cortical microtubules. In contrast, actin and sucrose synthase (which supplies UDP-glucose to callose synthase) are not permanently associated with callose synthase. Immunogold labeling showed strong colocalization of the enzyme and microtubules; this association is occasionally mediated by vesicles. The association between callose synthase and vesicles was also demonstrated by co-distribution between the enzyme and Rab11b; in addition, the not homogeneous distribution of callose synthase in cell membranes is also shown by analysis of membrane microdomains.

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