Preharvest methyl jasmonate application delays cell wall degradation and upregulates phenolic metabolism and antioxidant activities in cold stored raspberries.

The effects of preharvest methyl jasmonate (MeJA) spray application on the physicochemical quality, metabolism of phenolics, and cell wall components in raspberries were investigated during a 10-day cold storage period. MeJA spray reduced firmness loss, decay incidence, and weight loss, while maintained higher levels of soluble solids content, ascorbic acid, anthocyanins and flavonoids in raspberries. Furthermore, MeJA application resulted in increased total pectin and protopectin levels, as well as lowered water-soluble pectin, and activities of pectin methyl esterase, polygalacturonase and cellulase enzymes. Additionally, MeJA treatment upregulated the phenylpropanoid pathway, leading to higher endogenous phenolics and activities of phenylalanine-ammonia lyase and shikimate dehydrogenase. In conclusion, preharvest MeJA spray application could be adopted to enhance the storage potential of cold-stored raspberries for 10 days by maintaining higher firmness, assuring better physicochemical quality, and increasing phenolic metabolism, while reducing cell wall hydrolysis.

Comparison of kink-band structures and specificities of cell wall polysaccharides in modern and ancient flax fibres.

Flax (Linum usitatissimum L.) is a plant of industrial importance, its fibres being presently used for high-value textile applications, composite reinforcements as well as natural actuators. Human interest in this fibre-rich plant dates back several millennia, including to Ancient Egypt where flax was used extensively in various quotidian items. While the recent technical developments of flax fibres continue to diversify through scientific research, the historical use of flax also has rich lessons for today. Through careful examination of ancient Egyptian and modern flax fibres, this study aims to conduct a multi-scale characterization from the yarn to the fibre cell wall scale, linking differences in structure and polysaccharide content to the mechanical performance and durability of flax. Here, a multi-scale biochemical study is enriched by scanning electron microscopy and nanomechanical investigations. A key finding is the similarity of cellulose features, crystallinity index and local mechanical performances between ancient and modern fibres. Biochemically speaking, monosaccharides analysis, deep-UV and NMR investigations demonstrate that ancient fibres exhibit less pectins but a similar hemicellulosic content, especially through uronic acids and galactose, suggesting the sensitivity of these non-crystalline components.

[Aspergillus Cell Surface Structural Analysis and Its Applications to Industrial and Medical Use].

The hyphal surface of cells of filamentous fungi is covered with cell wall, which is mainly composed of polysaccharides. Since the cell wall is the first structure to come in contact with the infection host, the environment, and the fungus itself, the elucidation of the cell wall structure and biogenesis is essential for understanding fungal ecology. Among filamentous fungi, the genus Aspergillus is an important group in the industrial, food, and medical fields. It is known that Aspergillus species form hyphal pellets in shake liquid culture. The authors previously found the role of α-1,3-glucan in hyphal aggregation in Aspergillus species. In addition, extracellular polysaccharide galactosaminogalactan contributed to hyphal aggregation as well, and dual disruption of biosynthesis genes of α-1,3-glucan and galactosaminogalactan resulted in complete hyphal dispersion in shake liquid culture. The characteristic of mycelia to form pellets under liquid culture conditions was the main reason why the growth measurement methods used for unicellular organisms could not be applied. We reported that hyphal growth of the dual disruption mutant could be measured by optical density. A real-time plate reader could be used to determine the growth curve of the mycelial growth of the dual disruption mutant. This measurement approach not only provides basic microbiological insights in filamentous fungi, but also has the potential to be applied to high-throughput screening of anti-Aspergillus drugs.

Yeast polysaccharides: The environmentally friendly polysaccharides with broad application potentials.

Yeast cell wall (YCW) polysaccharides, including ß-glucans, mannans, chitins, and glycogens, can be extracted from the waste of beer industry. They are environmentally friendly, abundant, inexpensive raw materials, and have shown broad biological activities and application potentials. The exploitation of yeast polysaccharides is of great importance for environmental protection and resource utilization. This paper reviews the structural features and preparation of YCW polysaccharides. The solubility and emulsification of yeast polysaccharides and the properties of binding metal ions are presented. In addition, biological activities such as blood glucose and lipid lowering, immune regulation, antioxidant, promotion of intestinal health, and promotion of wound healing are proposed, highlighting the beneficial effects of yeast polysaccharides on human health. Through modification, the physical and chemical properties of yeast polysaccharides are changed, which emphasizes the promotion of their biological activities and properties. In addition, the food applications of yeast polysaccharides, including the food packaging film, emulsifier, thickening agent, and fat alternatives, are focused and discussed.

Communicating Across Cell Walls: Structure, Evolution, and Regulation of Plasmodesmatal Transport in Plants.

Plasmodesmata are conduits in plant cell walls that allow neighboring cells to communicate and exchange resources. Despite their central importance to plant development and physiology, our understanding of plasmodesmata is relatively limited compared to other subcellular structures. In recent years, technical advances in electron microscopy, mass spectrometry, and phylogenomics have illuminated the structure, composition, and evolution of plasmodesmata in diverse plant lineages. In parallel, forward genetic screens have revealed key signaling pathways that converge to regulate plasmodesmatal transport, including chloroplast-derived retrograde signaling, phytohormone signaling, and metabolic regulation by the conserved eukaryotic Target of Rapamycin kinase. This review summarizes our current knowledge of the structure, evolution, and regulation of plasmodesmatal transport in plants.

The Mycobacterium tuberculosis Cell Wall: An Alluring Drug Target for Developing Newer Anti-TB Drugs-A Perspective.

The Mycobacterium cell wall is a capsule-like structure comprising of various layers of biomolecules such as mycolic acid, peptidoglycans, and arabinogalactans, which provide the Mycobacteria a sort of cellular shield. Drugs like isoniazid, ethambutol, cycloserine, delamanid, and pretomanid inhibit cell wall synthesis by inhibiting one or the other enzymes involved in cell wall synthesis. Many enzymes present across these layers serve as potential targets for the design and development of newer anti-TB drugs. Some of these targets are currently being exploited as the most druggable targets like DprE1, InhA, and MmpL3. Many of the anti-TB agents present in clinical trials inhibit cell wall synthesis. The present article covers a systematic perspective of developing cell wall inhibitors targeting various enzymes involved in cell wall biosynthesis as potential drug candidates for treating Mtb infection.

Intracellular morphogenesis of diatom silica is guided by local variations in membrane curvature.

Silica cell-wall formation in diatoms is a showcase for the ability of organisms to control inorganic mineralization. The process of silicification by these unicellular algae is tightly regulated within a membrane-bound organelle, the silica deposition vesicle (SDV). Two opposing scenarios were proposed to explain the tight regulation of this intracellular process: a template-mediated process that relies on preformed scaffolds, or a template-independent self-assembly process. The present work points to a third scenario, where the SDV membrane is a dynamic mold that shapes the forming silica. We use in-cell cryo-electron tomography to visualize the silicification process in situ, in its native-state, and with a nanometer-scale resolution. This reveals that the plasma membrane interacts with the SDV membrane via physical tethering at membrane contact sites, where the curvature of the tethered side of the SDV membrane mirrors the intricate silica topography. We propose that silica growth and morphogenesis result from the biophysical properties of the SDV and plasma membranes.

Control of bacterial cell wall autolysins by peptidoglycan crosslinking mode.

To withstand their internal turgor pressure and external threats, most bacteria have a protective peptidoglycan (PG) cell wall. The growth of this PG polymer relies on autolysins, enzymes that create space within the structure. Despite extensive research, the regulatory mechanisms governing these PG-degrading enzymes remain poorly understood. Here, we unveil a novel and widespread control mechanism of lytic transglycosylases (LTs), a type of autolysin responsible for breaking down PG glycan chains. Specifically, we show that LD-crosslinks within the PG sacculus act as an inhibitor of LT activity. Moreover, we demonstrate that this regulation controls the release of immunogenic PG fragments and provides resistance against predatory LTs of both bacterial and viral origin. Our findings address a critical gap in understanding the physiological role of the LD-crosslinking mode in PG homeostasis, highlighting how bacteria can enhance their resilience against environmental threats, including phage attacks, through a single structural PG modification.

Transcription Factor VlbZIP14 Inhibits Postharvest Grape Berry Abscission by Directly Activating VlCOMT and Promoting Lignin Biosynthesis.

Sulfur dioxide (SO2) is the most effective preservative for table grapes as it reduces the respiratory intensity of berries and inhibits mold growth. However, excessive SO2 causes berry abscission during storage, resulting in an economic loss postharvest. In this study, grapes were exogenously treated with SO2, SO2 + 1.5% chitosan, SO2 + 1.5% eugenol, and SO2 + eugenol-loaded chitosan nanoparticles (SN). In comparison to SO2 treatment, SN treatment reduced the berries' abscission rate by 74% while maintaining the quality of the berries. Among the treatments, SN treatment most effectively inhibited berry abscission and maintained berry quality. RNA-sequencing (RNA-seq) revealed that SN treatment promoted the expression of genes related to cell wall metabolism. Among these genes, VlCOMT was detected as the central gene, playing a key role in mediating the effects of SN. Dual luciferase and yeast one-hybrid (Y1H) assays demonstrated that VlbZIP14 directly activated VlCOMT by binding to the G-box motif in the latter's promoter, which then participated in lignin synthesis. Our results provide key insights into the molecular mechanisms underlying the SN-mediated inhibition of berry abscission and could be used to improve the commercial value of SO2-treated postharvest table grapes.

The roles of cell wall polysaccharides in response to waterlogging stress in Brassica napus L. root.

BACKGROUND: Brassica napus L. (B. napus) is susceptible to waterlogging stress during different cultivation periods. Therefore, it is crucial to enhance the resistance to waterlogging stress to achieve a high and stable yield of B. napus. RESULTS: Here we observed significant differences in the responses of two B. napus varieties in root under waterlogging stress. The sensitive variety (23651) exhibited a more pronounced and rapid reduction in cell wall thickness and root integrity compared with the tolerant variety (Santana) under waterlogging stress. By module clustering analysis based on transcriptome data, we identified that cell wall polysaccharide metabolism responded to waterlogging stress in root. It was found that pectin content was significantly reduced in the sensitive variety compared with the tolerant variety. Furthermore, transcriptome analysis revealed that the expression of two homologous genes encoding polygalacturonase-inhibiting protein 2 (PGIP2), involved in polysaccharide metabolic pathways, was highly upregulated in root of the tolerant variety under waterlogging stress. BnaPGIP2s probably confer waterlogging resistance by inhibiting the activity of polygalacturonases (PGs), which in turn reduces the degradation of the pectin backbone polygalacturonic acid. CONCLUSIONS: Our findings demonstrate that cell wall polysaccharides in root plays a vital role in response to the waterlogging stress and provide a theoretical foundation for breeding waterlogging resistance in B. napus varieties.

New insights into the relationship between optical response and physicochemical properties in apple flesh: Hyperspectral microscope imaging technology.

Hyperspectral microscope imaging (HMI) technique was employed to assess the changes in physicochemical parameters and microstructure of 'Golden Delicious' apples flesh during storage. Four regions of interest (ROIs), including whole-cell ROI, intercellular space ROI, cytoplasm ROI, and cell wall ROI were investigated to assess their relationships with physicochemical parameters. Different ROIs presented similar vibrational profiles, but with slight differences in spectral intensity, especially in the range of 800-1000 nm. Spectral angle mapper (SAM) was applied to the HMI of apple tissues at different storage stages to clearly show the structural changes of parenchyma cells, while principal component analysis (PCA) could highlight the distribution of sugars, water and pigments in apple flesh at the cellular scale. Simultaneously with the degradation of acid-soluble pectin (ASP), middle lamella dissolution and increased intercellular space were observed using SEM and TEM. Single feature variables were used to construct linear models based on pearson correlation analysis, with R2 of 0.96 for moisture at 982 nm, 0.85 for water-soluble pectin (WSP) at 420 nm, 0.82 for L* at 946 nm, 0.77 for soluble solids content (SSC) at 484 nm, and 0.66 for firmness at 490 nm. This work demonstrated the great potential of HMI technology as a fast, accurate and efficient solution for assessing the quality of 'Golden Delicious' apples.

R2R3 MYB Transcription Factor GhMYB201 Promotes Cotton Fiber Elongation via Cell Wall Loosening and Very-Long-Chain Fatty Acid Synthesis.

Cotton fiber is the leading natural textile material, and fiber elongation plays an essential role in the formation of cotton yield and quality. Although a number of components in the molecular network controlling cotton fiber elongation have been reported, a lot of players still need to be functionally dissected to understand the regulatory mechanism of fiber elongation comprehensively. In the present study, an R2R3-MYB transcription factor gene, GhMYB201, was characterized and functionally verified via CRISPR/Cas9-mediated gene editing. GhMYB201 was homologous to Arabidopsis AtMYB60, and both coding genes (GhMYB201At and GhMYB201Dt) were preferentially expressed in elongating cotton fibers. Knocking-out of GhMYB201 significantly reduced the rate and duration of fiber elongation, resulting in shorter and coarser mature fibers. It was found that GhMYB201 could bind and activate the transcription of cell wall loosening genes (GhRDLs) and also ß-ketoacyl-CoA synthase genes (GhKCSs) to enhance very-long-chain fatty acid (VLCFA) levels in elongating fibers. Taken together, our data demonstrated that the transcription factor GhMYB201s plays an essential role in promoting fiber elongation via activating genes related to cell wall loosening and VLCFA biosynthesis.

Nitrate Starvation Induces Lateral Root Organogenesis in Triticum aestivum via Auxin Signaling.

The lateral root (LR) is an essential component of the plant root system, performing important functions for nutrient and water uptake in plants and playing a pivotal role in cereal crop productivity. Nitrate (NO3-) is an essential nutrient for plants. In this study, wheat plants were grown in 1/2 strength Hoagland's solution containing 5 mM NO3- (check; CK), 0.1 mM NO3- (low NO3-; LN), or 0.1 mM NO3- plus 60 mg/L 2,3,5-triiodobenzoic acid (TIBA) (LNT). The results showed that LN increased the LR number significantly at 48 h after treatment compared with CK, while not increasing the root biomass, and LNT significantly decreased the LR number and root biomass. The transcriptomic analysis showed that LN induced the expression of genes related to root IAA synthesis and transport and cell wall remodeling, and it was suppressed in the LNT conditions. A physiological assay revealed that the LN conditions increased the activity of IAA biosynthesis-related enzymes, the concentrations of tryptophan and IAA, and the activity of cell wall remodeling enzymes in the roots, whereas the content of polysaccharides in the LRP cell wall was significantly decreased compared with the control. Fourier-transform infrared spectroscopy and atomic microscopy revealed that the content of cell wall polysaccharides decreased and the cell wall elasticity of LR primordia (LRP) increased under the LN conditions. The effects of LN on IAA synthesis and polar transport, cell wall remodeling, and LR development were abolished when TIBA was applied. Our findings indicate that NO3- starvation may improve auxin homeostasis and the biological properties of the LRP cell wall and thus promote LR initiation, while TIBA addition dampens the effects of LN on auxin signaling, gene expression, physiological processes, and the root architecture.

The Impact of a Non-Pathogenic Strain of Fusarium Oxysporum on Structural and Biochemical Properties of Flax Suspension Cultures.

Flax (Linum usitatissimum L.) is an important crop plant with pharmaceutical significance. It is described in pharmacopoeias (the United States Pharmacopeia and the European Pharmacopoeia), which confirms that it (especially the seeds) is a valuable medicinal product. Similar to flax seeds, which accumulate bioactive compounds, flax in vitro cultures are also a rich source of flavonoids, phenolics, lignans and neolignans. In the present study, flax suspension cultures after treatment of the non-pathogenic Fusarium oxysporum strain Fo47 were established and analyzed. The study examined the suitability of Fo47 as an elicitor in flax suspension cultures and provided interesting data on the impact of these endophytic fungi on plant metabolism and physiology. Two flax cultivars (Bukoz and Nike) and two compositions of media for flax callus liquid cultures were tested. Biochemical analysis revealed enhanced levels of secondary metabolites (total flavonoid and total phenolic content) and photosynthetically active pigments in the flax callus cultures after treatment with the non-pathogenic fungal strain F. oxysporum Fo47 when compared to control, untreated cultures. In cultures with the selected, optimized conditions, FTIR analysis was performed and revealed changes in the structural properties of cell wall polymers after elicitation of cultures with F. oxysporum Fo47. The plant cell wall polymers were more strongly bound, and the crystallinity index (Icr) of cellulose was higher than in control, untreated samples. However, lignin and pectin levels were lower in the flax callus liquid cultures treated with the non-pathogenic strain of Fusarium when compared to the untreated control. The potential application of the non-pathogenic strain of F. oxysporum for enhancing the synthesis of desired secondary metabolites in plant tissue cultures is discussed.

Agents Targeting the Bacterial Cell Wall as Tools to Combat Gram-Positive Pathogens.

The cell wall is an indispensable element of bacterial cells and a long-known target of many antibiotics. Penicillin, the first discovered beta-lactam antibiotic inhibiting the synthesis of cell walls, was successfully used to cure many bacterial infections. Unfortunately, pathogens eventually developed resistance to it. This started an arms race, and while novel beta-lactams, either natural or (semi)synthetic, were discovered, soon upon their application, bacteria were developing resistance. Currently, we are facing the threat of losing the race since more and more multidrug-resistant (MDR) pathogens are emerging. Therefore, there is an urgent need for developing novel approaches to combat MDR bacteria. The cell wall is a reasonable candidate for a target as it differentiates not only bacterial and human cells but also has a specific composition unique to various groups of bacteria. This ensures the safety and specificity of novel antibacterial agents that target this structure. Due to the shortage of low-molecular-weight candidates for novel antibiotics, attention was focused on peptides and proteins that possess antibacterial activity. Here, we describe proteinaceous agents of various origins that target bacterial cell wall, including bacteriocins and phage and bacterial lysins, as alternatives to classic antibiotic candidates for antimicrobial drugs. Moreover, advancements in protein chemistry and engineering currently allow for the production of stable, specific, and effective drugs. Finally, we introduce the concept of selective targeting of dangerous pathogens, exemplified by staphylococci, by agents specifically disrupting their cell walls.

Antibacterial Activity of Novel Agent N-2-Hydroxypropyl Trimethyl Ammonium Chloride Chitosan against Streptococcus mutans.

Dental caries (DC) is one of the most common oral diseases and is mainly caused by Streptococcus mutans (S. mutans). The use of antibiotics against S. mutans usually has side effects, including developing resistance. N-2-Hydroxypropyl trimethyl ammonium chloride chitosan (N-2-HACC), a natural product, has great potential utility in antibacterial agents owing to its low toxicity and good biocompatibility. Thus, the purpose of the present study was to explore the antimicrobial activity of N-2-HACC against S. mutans through the permeability of the cell wall, integrity of cell membrane, protein and nucleic acid synthesis, respiratory metabolism, and biofilm formation. Our results confirmed that the MIC of N-2-HACC against S. mutans was 0.625 mg/mL with a 90.01 ± 1.54% inhibition rate. SEM observed the formation of cavities on the surface of S. mutans after 12 h N-2-HACC treatment. The level of alkaline phosphatase (AKP) activity was higher in the N-2-HACC treatment group than in the control group, indicating that N-2-HACC can improve the permeability of the cell wall. Also, N-2-HACC treatment can destroy the cell membrane of S. mutans by increasing conductivity and absorbance at 260 nm, decreasing cell metabolic activity, and enhancing the fluorescence at 488 nm. Respiratory metabolism revealed that the activities of the Na+-K+-ATP enzyme, pyruvate kinase (PK), succinate dehydrogenase (SDH), and malate dehydrogenase (MDH) were decreased after N-2-HACC treatment, revealing that N-2-HACC can inhibit glycolysis and the tricarboxylic acid cycle (TCA cycle) of S. mutans. Moreover, N-2-HACC can also decrease the contents of the nucleic acid and solution protein of S. mutans, interfere with biofilm formation, and decrease the mRNA expression level of biofilm formation-related genes. Therefore, these results verify that N-2-HACC has strong antibacterial activity against S. mutans, acting via cell membrane integrity damage, increasing the permeability of cell walls, interfering with bacterial protein and nucleic acid synthesis, perturbing glycolysis and the TCA cycle, and inhibiting biofilm formation. It is suggested that N-2-HACC may represent a new potential synthetically modified antibacterial material against S. mutans.

Research on the Cell Wall Breaking and Subcritical Extraction of Astaxanthin from Phaffia rhodozyma.

This study focused on developing an effective cell wall-breaking method for Phaffia rhodozyma, followed by utilizing subcritical fluid extraction to isolate, extract, and concentrate astaxanthin from the complex fermentation products of P. rhodozyma. A comprehensive comparison of seven distinct methods for disrupting cell walls, including dimethyl sulfoxide treatment, lactic acid treatment, sodium hydroxide treatment, ß-glucanase enzymatic digestion, ß-mannanase enzymatic digestion, and a combined enzymatic treatment involving both ß-mannanase and ß-glucanase was conducted. The results identified the lactic acid method as the most effective in disrupting the cell walls of P. rhodozyma. The software, Design Expert, was used in the process of extracting astaxanthin from cell lysates using a subcritical extraction method. Through fitting analysis and response surface optimization analysis by Design Expert, the optimal extraction conditions were determined as follows: an extraction temperature of 41 °C, extraction frequency of two times, and extraction time of 46 min. These parameters facilitated the efficient extraction, concentration, and enrichment of astaxanthin from P. rhodozyma, resulting in an astaxanthin concentration of 540.00 mg/L. This result can establish the foundation for its high-value applications.

GhPME36 aggravates susceptibility to Liriomyza sativae by affecting cell wall biosynthesis in cotton leaves.

BACKGROUND: Cotton is an important economic crop and a host of Liriomyza sativae. Pectin methylesterase (PME)-mediated pectin metabolism plays an indispensable role in multiple biological processes in planta. However, the pleiotropic functions of PME often lead to unpredictable effects on crop resistance to pests. Additionally, whether and how PME affects susceptibility to Liriomyza sativae remain unclear. RESULTS: Here, we isolated GhPME36, which is located in the cell wall, from upland cotton (Gossypium hirsutum L.). Interestingly, the overexpression of GhPME36 in cotton caused severe susceptibility to Liriomyza sativae but increased leaf biomass in Arabidopsis. Cytological observations revealed that the cell wall was thinner with more demethylesterified pectins in GhPME36-OE cotton leaves than in WT leaves, whereas the soluble sugar content of GhPME36-OE cotton leaf cell walls was accordingly higher; both factors attracted Liriomyza sativae to feed on GhPME36-OE cotton leaves. Metabolomic analysis demonstrated that glucose was significantly differentially accumulated. Transcriptomic analysis further revealed DEGs enriched in glucose metabolic pathways when GhPME36 was overexpressed, suggesting that GhPME36 aggravates susceptibility to Liriomyza sativae by affecting both the structure and components of cell wall biosynthesis. Moreover, GhPME36 interacts with another pectin-modifying enzyme, GhC/VIF1, to maintain the dynamic stability of pectin methyl esterification. CONCLUSIONS: Taken together, our results reveal the cytological and molecular mechanisms by which GhPME36 aggravates susceptibility to Liriomyza sativae. This study broadens the knowledge of PME function and provides new insights into plant resistance to pests and the safety of genetically modified plants.

Cell wall melanin impedes growth of the Cryptococcus neoformans polysaccharide capsule by sequestering calcium.

Cryptococcus neoformans has emerged as a frontrunner among deadly fungal pathogens and is particularly life-threatening for many HIV-infected individuals with compromised immunity. Multiple virulence factors contribute to the growth and survival of C. neoformans within the human host, the two most prominent of which are the polysaccharide capsule and melanin. As both of these features are associated with the cell wall, we were interested to explore possible cooperative or competitive interactions between these two virulence factors. Whereas capsule thickness had no effect on the rate at which cells became melanized, build-up of the melanin pigment layer resulted in a concomitant loss of polysaccharide material, leaving melanized cells with significantly thinner capsules than their nonmelanized counterparts. When melanin was provided exogenously to cells in a transwell culture system we observed a similar inhibition of capsule growth and maintenance. Our results show that melanin sequesters calcium thereby limiting its availability to form divalent bridges between polysaccharide subunits required for outer capsule assembly. The decreased ability of melanized cells to incorporate exported polysaccharide into the growing capsule correlated with the amount of shed polysaccharide, which could have profound negative impacts on the host immune response.

Mycobacterium tuberculosis protein Rv2652c enhances intracellular survival by inhibiting host immune responses.

BACKGROUNDS: Mycobacterium tuberculosis (Mtb), the pathogen responsible for tuberculosis, secretes a multitude of proteins that modulate the host's immune response to ensure its own persistence. The region of difference (RD) genes encoding proteins play key roles in TB immunity and pathogenesis. Nevertheless, the roles of the majority of RD-encoded proteins remain to be elucidated. OBJECTS: To elucidate the role of Rv2652c located in RD13 in Mtb on bacterial growth, bacterial survival, and host immune response. METHODS: We constructed the strain MS_Rv2652c which over-expresses Mtb RD-encoding protein Rv2652c in M. smegmatis (MS), and compared it with the wild strain in the bacterial growth, bacterial survival, virulence of Rv2652c, and determined the effect of MS_Rv2652c on host immune response in macrophages. RESULTS: Rv2652c protein is located at cell wall of MS_Rv2652c strain and also an integral component of the Mtb H37Rv cell wall. Rv2652c can enhance the resistance of recombinant MS to various stressors. Moreover, Rv2652c inhibits host proinflammatory responses via modulation of the NF-κB pathway, thereby promoting Mtb survival in vitro and in vivo. CONCLUSION: Our data suggest that cell wall protein Rv2652c plays an important role in creating a favorable environment for bacterial survival by modulating host signals and could be established as a potential TB drug target.