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

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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SEM and fluorescence imaging of callose deposition in root hair tips and suspension cultures of Streptanthus tortuosus

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100161047 ◽

1990 ◽

Vol 48 (3) ◽

pp. 698-699

Author(s):

K.S. Walters ◽

R.D. Sjolund ◽

K.C. Moore

Keyword(s):

Cell Wall ◽

Root Hair ◽

Cultured Cells ◽

Root Hairs ◽

Callus Cultures ◽

Callose Deposition ◽

Culture Cells ◽

Wall Structures ◽

Ultraviolet Illumination ◽

Callose Formation

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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Subcellular and supracellular mechanical stress prescribes cytoskeleton behavior in Arabidopsis cotyledon pavement cells

eLife ◽

10.7554/elife.01967 ◽

2014 ◽

Vol 3 ◽

Cited By ~ 169

Author(s):

Arun Sampathkumar ◽

Pawel Krupinski ◽

Raymond Wightman ◽

Pascale Milani ◽

Alexandre Berquand ◽

...

Keyword(s):

Cell Wall ◽

Mechanical Stress ◽

Cell Shape ◽

Tissue Level ◽

Pavement Cells ◽

Force Microscopy ◽

Atomic Force ◽

Response To Stress ◽

Maximal Tensile Stress ◽

Open Question

Although it is a central question in biology, how cell shape controls intracellular dynamics largely remains an open question. Here, we show that the shape of Arabidopsis pavement cells creates a stress pattern that controls microtubule orientation, which then guides cell wall reinforcement. Live-imaging, combined with modeling of cell mechanics, shows that microtubules align along the maximal tensile stress direction within the cells, and atomic force microscopy demonstrates that this leads to reinforcement of the cell wall parallel to the microtubules. This feedback loop is regulated: cell-shape derived stresses could be overridden by imposed tissue level stresses, showing how competition between subcellular and supracellular cues control microtubule behavior. Furthermore, at the microtubule level, we identified an amplification mechanism in which mechanical stress promotes the microtubule response to stress by increasing severing activity. These multiscale feedbacks likely contribute to the robustness of microtubule behavior in plant epidermis.

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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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Tissue-Specific Hormonal Variations in Grapes of Irrigated and Non-irrigated Grapevines (Vitis vinifera cv. “Merlot”) Growing Under Mediterranean Field Conditions

Frontiers in Plant Science ◽

10.3389/fpls.2021.621587 ◽

2021 ◽

Vol 12 ◽

Author(s):

Camila Ribalta-Pizarro ◽

Paula Muñoz ◽

Sergi Munné-Bosch

Keyword(s):

Water Supply ◽

Agricultural Practices ◽

Growth Dynamics ◽

Tissue Level ◽

Grape Berry ◽

Wine Quality ◽

Tissue Specific ◽

Grape Quality ◽

Comparison Results ◽

Isopentenyl Adenine

Agricultural practices in grapevines management include water restrictions due to its positive effect on wine quality, especially when applied at fruit ripening. Although the effects of water stress in some groups of phytohormones have already been described in leaves and whole grapes, information regarding tissue-specific variations in hormones during ripening in grapes is scarce. Field-grown grapevines from the cv. “Merlot” were subjected to two differential water supplies, including only rainfed, non-irrigated vines (T0) and vines additionally irrigated with 25Lweek−1 vine−1 (T1). Tissue-specific variations in the hormonal profiling of grapes [including changes in the contents of abscisic acid (ABA), jasmonic acid (JA), salicylic acid (SA), the ethylene precursor 1-amino-cyclopropane-1-carboxylic acid (ACC), the auxin indole-3-acetic acid, gibberellins 1, 3, 4, and 7 (GA1, GA3, GA4, and GA7), the cytokinins trans-zeatin, and 2-isopentenyl adenine, including as well their respective ribosylated forms] were periodically evaluated from veraison to harvest. The hormonal profiling in leaves was also measured at the beginning and end of the season for comparison. Results showed that grape growth dynamics were transiently affected by the differences in water regimes, the increased water supply leading to an accelerated growth, slightly reduced accumulation of sugars, and transiently lowered pH, although grape quality did not differ between treatments at harvest. Hormonal profiling of whole berries did not reveal any difference in the endogenous contents of phytohormones between treatments, except for a transient decrease in GA4 contents in T1 compared to T0 vines, which was not confirmed at the tissular level. Hormonal profiling at the tissue level highlighted a differential accumulation of phytohormones during ripening in berry tissues, with pulps being particularly poor in ABA, JA, and SA contents, seeds particularly accumulating ACC, gibberellins, and zeatin-type cytokinins, and the skin being particularly rich in auxin and active cytokinins. Changes in water supply led to very small and transient changes in the endogenous contents of phytohormones in the seeds, pulp, and skin of berries, the most remarkable variations being observed in cytokinin contents, which increased earlier [between 5 and 12days after veraison (DAV)] but later kept more constant in the skin from T1 compared to T0 vines and were also 3-fold higher at 40 DAV in seeds of T1 compared to T0 vines. It is concluded that small changes in water supply can trigger hormonal-driven physiological adjustments at the tissular level affecting the evolution of fruit growth and quality throughout grape berry ripening.

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Exogenous proanthocyanidins improve tolerance of Cu-toxicity by amelioration of oxidative damage and re-programming of gene expression in Medicago sativa

PLoS ONE ◽

10.1371/journal.pone.0259100 ◽

2021 ◽

Vol 16 (10) ◽

pp. e0259100

Author(s):

Siyi Zhao ◽

Yanqiao Zhu ◽

Wenwen Liu ◽

Xiaoshan Wang ◽

Han Wang ◽

...

Keyword(s):

Oxidative Stress ◽

Cell Wall ◽

Ascorbic Acid ◽

Plant Growth ◽

Medicago Sativa ◽

Agricultural Practices ◽

Cell Wall Synthesis ◽

Genes Encoding ◽

Stress Damage ◽

The Impact

Excess copper (Cu) in soil due to industrial and agricultural practices can result in reduced plant growth. Excess Cu resulted in severely retarded root growth with severe discoloration of Alfalfa (Medicago sativa) and Medicago truncatula. Growth in the presence of hydrogen peroxide resulted in similar symptoms that could be partially recovered by the addition of the reductant ascorbic acid revealing damage was likely due to oxidative stress. The addition of proanthocyanidins (PAs) in the presence of Cu prevented much of the damage, including plant growth and restoration of lignin synthesis which was inhibited in the presence of excess Cu. Transcriptome analyses of the impact of excess Cu and the amelioration after PAs treatment revealed that changes were enriched in functions associated with the cell wall and extracellular processes, indicating that inhibition of cell wall synthesis was likely the reason for retarded growth. Excess Cu appeared to induce a strong defense response, along with alterations in the expression of a number of genes encoding transcription factors, notably related to ethylene signaling. The addition of PAs greatly reduced this response, and also induced novel genes that likely help ameliorate the effects of excess Cu. These included induction of genes involved in the last step of ascorbic acid biosynthesis and of enzymes involved in cell wall synthesis. Combined, these results show that excess Cu causes severe oxidative stress damage and inhibition of cell wall synthesis, which can be relieved by the addition of PAs.

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Manganese distribution in the Mn-hyperaccumulator Grevillea meisneri from New Caledonia

10.21203/rs.3.rs-393514/v1 ◽

2021 ◽

Author(s):

Camille Bihanic ◽

Eddy Petit ◽

Roseline Perrot ◽

Lucie Cases ◽

Armelle Garcia ◽

...

Keyword(s):

Large Scale ◽

New Caledonia ◽

Tissue Level ◽

Cluster Roots ◽

Transport Pathways ◽

X Ray ◽

Mining Sites ◽

Rehabilitation Programs ◽

Primary Roots ◽

Preferential Uptake

Abstract • Grevillea meisneri, an endemic New Caledonian Mn-hyperaccumulator, is used in rehabilitation of degraded mining sites on the island. Large-scale programs require transplanting nursery-grown seedlings, but effects of the nursery environment on Mn tolerance of transplants and their capacity to hyper-accumulate Mn are unknown, slowing rehabilitation efforts.• We studied tissue-level distribution of Mn and other elements in different tissues of G. meisneri using micro-X-Ray Fluorescence spectroscopy (μXRF), comparing nursery-grown plants transplanted into the site and sampled seven years later, and similar-sized plants that had grown spontaneously in the site. • Mirroring patterns in other Mn-hyperaccumulators, Mn was preferentially accumulated in leaves but was also present in roots. Concentrations were highest in leaf epidermal tissues, in cortex and vascular tissues of stems and primary roots, and in phloem and pericycle-endodermis of parent cluster roots. Although abundant in soil, Ni was absent from all tissues of G. meisneri. Ca was always co-localised with Mn. Preferential uptake of Mn vs Ni in roots implies as-yet-uncharacterized specific Mn-transporters, while Ca and Mn co-localisation suggests shared transport pathways. • No differences were observed in concentration and distribution of Mn in transplanted and spontaneously-growing plants. Nursery-grown transplants should be highly suitable for large-scale, high-throughput rehabilitation programs.

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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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