Cell Wall Mannoproteins from Yeast Affect Salivary Protein–Flavanol Interactions through Different Molecular Mechanisms

AbstractBackgroundBanana plant height is an important trait for horticultural practices and semi-dwarf cultivars show better resistance to damages by wind and rain. However, the molecular mechanisms controlling the pseudostem height remain poorly understood. Herein, we studied the molecular changes in the pseudostem of a semi-dwarf banana mutant Aifen No. 1 (Musaspp. Pisang Awak sub-group ABB) as compared to its wild-type dwarf cultivar using a combined transcriptome and metabolome approach.ResultsA total of 127 differentially expressed genes and 48 differentially accumulated metabolites were detected between the mutant and its wild type. Metabolites belonging to amino acid and its derivatives, flavonoids, lignans, coumarins, organic acids, and phenolic acids were up-regulated in the mutant. The transcriptome analysis showed the differential regulation of genes related to the gibberellin pathway, auxin transport, cell elongation, and cell wall modification. Based on the regulation of gibberellin and associated pathway-related genes, we discussed the involvement of gibberellins in pseudostem elongation in the mutant banana. Genes and metabolites associated with cell wall were explored and their involvement in cell extension is discussed.ConclusionsThe results suggest that gibberellins and associated pathways are possibly developing the observed semi-dwarf pseudostem phenotype together with cell elongation and cell wall modification. The findings increase the understanding of the mechanisms underlying banana stem height and provide new clues for further dissection of specific gene functions.

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Arabinogalactan Proteins in Plant Roots – An Update on Possible Functions

Frontiers in Plant Science ◽

10.3389/fpls.2021.674010 ◽

2021 ◽

Vol 12 ◽

Author(s):

Dagmar Hromadová ◽

Aleš Soukup ◽

Edita Tylová

Keyword(s):

Cell Wall ◽

Regulatory Networks ◽

Developmental Plasticity ◽

Molecular Mechanisms ◽

Arabinogalactan Proteins ◽

Cellular Level ◽

Environmental Response ◽

Essential Components ◽

Surface Signaling ◽

Cell Surface Signaling

Responsiveness to environmental conditions and developmental plasticity of root systems are crucial determinants of plant fitness. These processes are interconnected at a cellular level with cell wall properties and cell surface signaling, which involve arabinogalactan proteins (AGPs) as essential components. AGPs are cell-wall localized glycoproteins, often GPI-anchored, which participate in root functions at many levels. They are involved in cell expansion and differentiation, regulation of root growth, interactions with other organisms, and environmental response. Due to the complexity of cell wall functional and regulatory networks, and despite the large amount of experimental data, the exact molecular mechanisms of AGP-action are still largely unknown. This dynamically evolving field of root biology is summarized in the present review.

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FRA1 modulates cortical microtubule localization of CMU proteins

10.1101/760389 ◽

2019 ◽

Author(s):

Anindya Ganguly ◽

Chuanmei Zhu ◽

Weizu Chen ◽

Ram Dixit

Keyword(s):

Arabidopsis Thaliana ◽

Cell Wall ◽

Molecular Mechanisms ◽

Cortical Microtubule ◽

Cellulose Synthase ◽

Lateral Stability ◽

Cortical Microtubules ◽

Tail Region ◽

Opposing Effect ◽

Growth And Reproduction

ABSTRACTConstruction of the cell wall demands harmonized deposition of cellulose and matrix polysaccharides. Cortical microtubules orient the deposition of cellulose by guiding the trajectory of plasma membrane-embedded cellulose synthase complexes. Vesicles containing matrix polysaccharides are thought to be transported by the FRA1 kinesin to facilitate their secretion along cortical microtubules. The cortical microtubule cytoskeleton thus provides a platform to coordinate the delivery of cellulose and matrix polysaccharides, but the underlying molecular mechanisms remain unknown. Here, we show that the tail region of the FRA1 kinesin physically interacts with CMU proteins which are important for the microtubule-dependent guidance of cellulose synthase complexes. Interaction with CMUs did not affect microtubule binding or motility of the FRA1 kinesin but had an opposing effect on the cortical microtubule localization of CMU1 and CMU2 proteins, thus regulating the lateral stability of cortical microtubules. Phosphorylation of the FRA1 tail region by CKL6 inhibited binding to CMUs and consequently reversed the extent of cortical microtubule decoration by CMU1 and CMU2. Genetic experiments demonstrated the significance of this interaction to the growth and reproduction of Arabidopsis thaliana plants. We propose that modulation of CMU’s microtubule localization by FRA1 provides a mechanism to control the coordinated deposition of cellulose and matrix polysaccharides.

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Bacterial Quorum-Quenching Lactonase Hydrolyzes Fungal Mycotoxin and Reduces Pathogenicity of Penicillium expansum—Suggesting a Mechanism of Bacterial Antagonism

Journal of Fungi ◽

10.3390/jof7100826 ◽

2021 ◽

Vol 7 (10) ◽

pp. 826

Author(s):

Shlomit Dor ◽

Dov Prusky ◽

Livnat Afriat-Jurnou

Keyword(s):

Cell Wall ◽

Quorum Sensing ◽

Virulence Factors ◽

Molecular Mechanisms ◽

Recombinant Expression ◽

Bacterial Species ◽

Quorum Quenching ◽

Host Cells ◽

Penicillium Expansum ◽

Fungal Colonization

Penicillium expansum is a necrotrophic wound fungal pathogen that secrets virulence factors to kill host cells including cell wall degrading enzymes (CWDEs), proteases, and mycotoxins such as patulin. During the interaction between P. expansum and its fruit host, these virulence factors are strictly modulated by intrinsic regulators and extrinsic environmental factors. In recent years, there has been a rapid increase in research on the molecular mechanisms of pathogenicity in P. expansum; however, less is known regarding the bacteria–fungal communication in the fruit environment that may affect pathogenicity. Many bacterial species use quorum-sensing (QS), a population density-dependent regulatory mechanism, to modulate the secretion of quorum-sensing signaling molecules (QSMs) as a method to control pathogenicity. N-acyl homoserine lactones (AHLs) are Gram-negative QSMs. Therefore, QS is considered an antivirulence target, and enzymes degrading these QSMs, named quorum-quenching enzymes, have potential antimicrobial properties. Here, we demonstrate that a bacterial AHL lactonase can also efficiently degrade a fungal mycotoxin. The mycotoxin is a lactone, patulin secreted by fungi such as P. expansum. The bacterial lactonase hydrolyzed patulin at high catalytic efficiency, with a kcat value of 0.724 ± 0.077 s−1 and KM value of 116 ± 33.98 μM. The calculated specific activity (kcat/KM) showed a value of 6.21 × 103 s−1M−1. While the incubation of P. expansum spores with the purified lactonase did not inhibit spore germination, it inhibited colonization by the pathogen in apples. Furthermore, adding the purified enzyme to P. expansum culture before infecting apples resulted in reduced expression of genes involved in patulin biosynthesis and fungal cell wall biosynthesis. Some AHL-secreting bacteria also express AHL lactonase. Here, phylogenetic and structural analysis was used to identify putative lactonase in P. expansum. Furthermore, following recombinant expression and purification of the newly identified fungal enzyme, its activity with patulin was verified. These results indicate a possible role for patulin and lactonases in inter-kingdom communication between fungi and bacteria involved in fungal colonization and antagonism and suggest that QQ lactonases can be used as potential antifungal post-harvest treatment.

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Cardiolipin Alters Rhodobacter sphaeroides Cell Shape by Affecting Peptidoglycan Precursor Biosynthesis

mBio ◽

10.1128/mbio.02401-18 ◽

2019 ◽

Vol 10 (1) ◽

Cited By ~ 4

Author(s):

Ti-Yu Lin ◽

William S. Gross ◽

George K. Auer ◽

Douglas B. Weibel

Keyword(s):

Cell Wall ◽

Rhodobacter Sphaeroides ◽

Cell Morphology ◽

Cell Shape ◽

Molecular Mechanisms ◽

Wild Type ◽

Anionic Phospholipid ◽

Content Type ◽

Lipid Ii ◽

Topological Features

ABSTRACT Cardiolipin (CL) is an anionic phospholipid that plays an important role in regulating protein biochemistry in bacteria and mitochondria. Deleting the CL synthase gene (Δcls) in Rhodobacter sphaeroides depletes CL and decreases cell length by 20%. Using a chemical biology approach, we found that a CL deficiency does not impair the function of the cell wall elongasome in R. sphaeroides; instead, biosynthesis of the peptidoglycan (PG) precursor lipid II is decreased. Treating R. sphaeroides cells with fosfomycin and d-cycloserine inhibits lipid II biosynthesis and creates phenotypes in cell shape, PG composition, and spatial PG assembly that are strikingly similar to those seen with R. sphaeroides Δcls cells, suggesting that CL deficiency alters the elongation of R. sphaeroides cells by reducing lipid II biosynthesis. We found that MurG—a glycosyltransferase that performs the last step of lipid II biosynthesis—interacts with anionic phospholipids in native (i.e., R. sphaeroides) and artificial membranes. Lipid II production decreases 25% in R. sphaeroides Δcls cells compared to wild-type cells, and overexpression of MurG in R. sphaeroides Δcls cells restores their rod shape, indicating that CL deficiency decreases MurG activity and alters cell shape. The R. sphaeroides Δcls mutant is more sensitive than the wild-type strain to antibiotics targeting PG synthesis, including fosfomycin, d-cycloserine, S-(3,4-dichlorobenzyl)isothiourea (A22), mecillinam, and ampicillin, suggesting that CL biosynthesis may be a potential target for combination chemotherapies that block the bacterial cell wall. IMPORTANCE The phospholipid composition of the cell membrane influences the spatial and temporal biochemistry of cells. We studied molecular mechanisms connecting membrane composition to cell morphology in the model bacterium Rhodobacter sphaeroides. The peptidoglycan (PG) layer of the cell wall is a dominant component of cell mechanical properties; consequently, it has been an important antibiotic target. We found that the anionic phospholipid cardiolipin (CL) plays a role in determination of the shape of R. sphaeroides cells by affecting PG precursor biosynthesis. Removing CL in R. sphaeroides alters cell morphology and increases its sensitivity to antibiotics targeting proteins synthesizing PG. These studies provide a connection to spatial biochemical control in mitochondria, which contain an inner membrane with topological features in common with R. sphaeroides.

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Genome-wide transcriptional changes triggered by water deficit on a drought-tolerant common bean cultivar

BMC Plant Biology ◽

10.1186/s12870-020-02664-1 ◽

2020 ◽

Vol 20 (1) ◽

Cited By ~ 1

Author(s):

Josefat Gregorio Jorge ◽

Miguel Angel Villalobos-López ◽

Karen Lizeth Chavarría-Alvarado ◽

Selma Ríos-Meléndez ◽

Melina López-Meyer ◽

...

Keyword(s):

Cell Wall ◽

Drought Tolerance ◽

Common Bean ◽

Crop Production ◽

Molecular Mechanisms ◽

Molecular Data ◽

Transcriptional Level ◽

Cell Periphery ◽

Enriched Categories ◽

Drought Tolerant

Abstract Background Common bean (Phaseolus vulgaris L.) is a relevant crop cultivated over the world, largely in water insufficiency vulnerable areas. Since drought is the main environmental factor restraining worldwide crop production, efforts have been invested to amend drought tolerance in commercial common bean varieties. However, scarce molecular data are available for those cultivars of P. vulgaris with drought tolerance attributes. Results As a first approach, Pinto Saltillo (PS), Azufrado Higuera (AH), and Negro Jamapa Plus (NP) were assessed phenotypically and physiologically to determine the outcome in response to drought on these common bean cultivars. Based on this, a Next-generation sequencing approach was applied to PS, which was the most drought-tolerant cultivar to determine the molecular changes at the transcriptional level. The RNA-Seq analysis revealed that numerous PS genes are dynamically modulated by drought. In brief, 1005 differentially expressed genes (DEGs) were identified, from which 645 genes were up-regulated by drought stress, whereas 360 genes were down-regulated. Further analysis showed that the enriched categories of the up-regulated genes in response to drought fit to processes related to carbohydrate metabolism (polysaccharide metabolic processes), particularly genes encoding proteins located within the cell periphery (cell wall dynamics). In the case of down-regulated genes, heat shock-responsive genes, mainly associated with protein folding, chloroplast, and oxidation-reduction processes were identified. Conclusions Our findings suggest that secondary cell wall (SCW) properties contribute to P. vulgaris L. drought tolerance through alleviation or mitigation of drought-induced osmotic disturbances, making cultivars more adaptable to such stress. Altogether, the knowledge derived from this study is significant for a forthcoming understanding of the molecular mechanisms involved in drought tolerance on common bean, especially for drought-tolerant cultivars such as PS.

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Molecular and physiological mechanisms underlying magnesium-deficiency-induced enlargement, cracking and lignification of Citrus sinensis leaf veins

Tree Physiology ◽

10.1093/treephys/tpaa059 ◽

2020 ◽

Vol 40 (9) ◽

pp. 1277-1291 ◽

Cited By ~ 3

Author(s):

Xin Ye ◽

Xu-Feng Chen ◽

Li-Ya Cai ◽

Ning-Wei Lai ◽

Chong-Ling Deng ◽

...

Keyword(s):

Cell Wall ◽

Citrus Sinensis ◽

Molecular Mechanisms ◽

Rho Gtpase ◽

Magnesium Deficiency ◽

Lignin Biosynthesis ◽

Starch Accumulation ◽

Ascorbate Oxidase ◽

Mg Deficiency ◽

Leaf Veins

Abstract Little is known about the physiological and molecular mechanisms underlying magnesium (Mg)-deficiency-induced enlargement, cracking and lignification of midribs and main lateral veins of Citrus leaves. Citrus sinensis (L.) Osbeck seedlings were irrigated with nutrient solution at a concentration of 0 (Mg-deficiency) or 2 (Mg-sufficiency) mM Mg(NO3)2 for 16 weeks. Enlargement, cracking and lignification of veins occurred only in lower leaves, but not in upper leaves. Total soluble sugars (glucose + fructose + sucrose), starch and cellulose concentrations were less in Mg-deficiency veins of lower leaves (MDVLL) than those in Mg-sufficiency veins of lower leaves (MSVLL), but lignin concentration was higher in MDVLL than that in MSVLL. However, all four parameters were similar between Mg-deficiency veins of upper leaves (MDVUL) and Mg-sufficiency veins of upper leaves (MSVUL). Using label-free, liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis, we identified 1229 and 492 differentially abundant proteins (DAPs) in MDVLL vs MSVLL and MDVUL vs MSVUL, respectively. Magnesium-deficiency-induced alterations of Mg, nonstructural carbohydrates, cell wall components, and protein profiles were greater in veins of lower leaves than those in veins of upper leaves. The increased concentration of lignin in MDVLL vs MSVLL might be caused by the following factors: (i) repression of cellulose and starch accumulation promoted lignin biosynthesis; (ii) abundances of proteins involved in phenylpropanoid biosynthesis pathway, hormone biosynthesis and glutathione metabolism were increased; and (iii) the abundances of the other DAPs [viz., copper/zinc-superoxide dismutase, ascorbate oxidase (AO) and ABC transporters] involved in lignin biosynthesis were elevated. Also, the abundances of several proteins involved in cell wall metabolism (viz., expansins, Rho GTPase-activating protein gacA, AO, monocopper oxidase-like protein and xyloglucan endotransglucosylase/hydrolase) were increased in MDVLL vs MSVLL, which might be responsible for the enlargement and cracking of leaf veins.

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The Cell Wall Lipid PDIM Contributes to Phagosomal Escape and Host Cell Exit of Mycobacterium tuberculosis

mBio ◽

10.1128/mbio.00148-17 ◽

2017 ◽

Vol 8 (2) ◽

Cited By ~ 73

Author(s):

Jeff Quigley ◽

V. Keith Hughitt ◽

Carlos A. Velikovsky ◽

Roy A. Mariuzza ◽

Najib M. El-Sayed ◽

...

Keyword(s):

Cell Wall ◽

Mycobacterium Tuberculosis ◽

Host Cell ◽

Molecular Mechanisms ◽

Transcriptional Repressor ◽

Cell Manipulation ◽

Human Pathogen ◽

Cell Necrosis ◽

Unique Cell ◽

Intracellular Vacuole

ABSTRACT The cell wall of Mycobacterium tuberculosis is composed of unique lipids that are important for pathogenesis. Indeed, the first-ever genetic screen in M. tuberculosis identified genes involved in the biosynthesis and transport of the cell wall lipid PDIM (phthiocerol dimycocerosates) as crucial for the survival of M. tuberculosis in mice. Here we show evidence for a novel molecular mechanism of the PDIM-mediated virulence in M. tuberculosis. We characterized the DNA interaction and the regulon of Rv3167c, a transcriptional repressor that is involved in virulence regulation of M. tuberculosis, and discovered that it controls the PDIM operon. A loss-of-function genetic approach showed that PDIM levels directly correlate with the capacity of M. tuberculosis to escape the phagosome and induce host cell necrosis and macroautophagy. In conclusion, our study attributes a novel role of the cell wall lipid PDIM in intracellular host cell modulation, which is important for host cell exit and dissemination of M. tuberculosis. IMPORTANCE Mycobacterium tuberculosis is a major human pathogen that has coevolved with its host for thousands of years. The complex and unique cell wall of M. tuberculosis contains the lipid PDIM (phthiocerol dimycocerosates), which is crucial for virulence of the bacterium, but its function is not well understood. Here we show that PDIM expression by M. tuberculosis is negatively regulated by a novel transcriptional repressor, Rv3167c. In addition, we discovered that the escape of M. tuberculosis from its intracellular vacuole was greatly augmented by the presence of PDIM. The increased release of M. tuberculosis into the cytosol led to increased host cell necrosis. The discovery of a link between the cell wall lipid PDIM and a major pathogenesis pathway of M. tuberculosis provides important insights into the molecular mechanisms of host cell manipulation by M. tuberculosis. IMPORTANCE Mycobacterium tuberculosis is a major human pathogen that has coevolved with its host for thousands of years. The complex and unique cell wall of M. tuberculosis contains the lipid PDIM (phthiocerol dimycocerosates), which is crucial for virulence of the bacterium, but its function is not well understood. Here we show that PDIM expression by M. tuberculosis is negatively regulated by a novel transcriptional repressor, Rv3167c. In addition, we discovered that the escape of M. tuberculosis from its intracellular vacuole was greatly augmented by the presence of PDIM. The increased release of M. tuberculosis into the cytosol led to increased host cell necrosis. The discovery of a link between the cell wall lipid PDIM and a major pathogenesis pathway of M. tuberculosis provides important insights into the molecular mechanisms of host cell manipulation by M. tuberculosis.

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Sugar Beet (Beta vulgaris) Guard Cells Responses to Salinity Stress: A Proteomic Analysis

International Journal of Molecular Sciences ◽

10.3390/ijms21072331 ◽

2020 ◽

Vol 21 (7) ◽

pp. 2331

Author(s):

Fatemeh Rasouli ◽

Ali Kiani-Pouya ◽

Leiting Li ◽

Heng Zhang ◽

Zhonghua Chen ◽

...

Keyword(s):

Cell Wall ◽

Sugar Beet ◽

Molecular Mechanisms ◽

Stress Proteins ◽

Lipid Transfer Protein ◽

Guard Cells ◽

Ascorbate Oxidase ◽

Carbon Gain ◽

Inorganic Pyrophosphatase ◽

Cell Wall Modification

Soil salinity is a major environmental constraint affecting crop growth and threatening global food security. Plants adapt to salinity by optimizing the performance of stomata. Stomata are formed by two guard cells (GCs) that are morphologically and functionally distinct from the other leaf cells. These microscopic sphincters inserted into the wax-covered epidermis of the shoot balance CO2 intake for photosynthetic carbon gain and concomitant water loss. In order to better understand the molecular mechanisms underlying stomatal function under saline conditions, we used proteomics approach to study isolated GCs from the salt-tolerant sugar beet species. Of the 2088 proteins identified in sugar beet GCs, 82 were differentially regulated by salt treatment. According to bioinformatics analysis (GO enrichment analysis and protein classification), these proteins were involved in lipid metabolism, cell wall modification, ATP biosynthesis, and signaling. Among the significant differentially abundant proteins, several proteins classified as “stress proteins” were upregulated, including non-specific lipid transfer protein, chaperone proteins, heat shock proteins, inorganic pyrophosphatase 2, responsible for energized vacuole membrane for ion transportation. Moreover, several antioxidant enzymes (peroxide, superoxidase dismutase) were highly upregulated. Furthermore, cell wall proteins detected in GCs provided some evidence that GC walls were more flexible in response to salt stress. Proteins such as L-ascorbate oxidase that were constitutively high under both control and high salinity conditions may contribute to the ability of sugar beet GCs to adapt to salinity by mitigating salinity-induced oxidative stress.

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Four New Genes of Cyanobacterium Synechococcus elongatus PCC 7942 Are Responsible for Sensitivity to 2-Nonanone

Microorganisms ◽

10.3390/microorganisms8081234 ◽

2020 ◽

Vol 8 (8) ◽

pp. 1234

Author(s):

Olga A. Koksharova ◽

Alexandra A. Popova ◽

Vladimir A. Plyuta ◽

Inessa A. Khmel

Keyword(s):

Cell Wall ◽

Transport System ◽

Molecular Mechanisms ◽

Synechococcus Elongatus ◽

Bacterial Cells ◽

New Genes ◽

Abc Transport ◽

Synechococcus Elongatus Pcc 7942 ◽

Pcc 7942 ◽

Restriction Modification

Microbial volatile organic compounds (VOCs) are cell metabolites that affect many physiological functions of prokaryotic and eukaryotic organisms. Earlier we have demonstrated the inhibitory effects of soil bacteria volatiles, including ketones, on cyanobacteria. Cyanobacteria are very sensitive to ketone action. To investigate the possible molecular mechanisms of the ketone 2-nonanone influence on cyanobacterium Synechococcus elongatus PCC 7942, we applied a genetic approach. After Tn5-692 transposon mutagenesis, several 2-nonanone resistant mutants have been selected. Four different mutant strains were used for identification of the impaired genes (Synpcc7942_1362, Synpcc7942_0351, Synpcc7942_0732, Synpcc7942_0726) that encode correspondingly: 1) a murein-peptide ligase Mpl that is involved in the biogenesis of cyanobacteria cell wall; 2) a putative ABC transport system substrate-binding proteins MlaD, which participates in ABC transport system that maintains lipid asymmetry in the gram-negative outer membrane by aberrantly localized phospholipids transport from outer to inner membranes of bacterial cells; 3) a conserved hypothetical protein that is encoding by gene belonging to phage gene cluster in Synechococcus elongatus PCC 7942 genome; 4) a protein containing the VRR-NUC (virus-type replication-repair nuclease) domain present in restriction-modification enzymes involved in replication and DNA repair. The obtained results demonstrated that 2-nonanone may have different targets in Synechococcus elongatus PCC 7942 cells. Among them are proteins involved in the biogenesis and functioning of the cyanobacteria cell wall (Synpcc7942_1362, Synpcc7942_0351, Synpcc7942_0732) and protein participating in stress response at DNA restriction-modification level (Synpcc7942_0726). This paper is the first report about the genes that encode protein products, which can be affected by 2-nonanone.

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