Search Results (329)

The spatial localization of plant secondary cell wall polymers is a controversial issue. A relief of parallel-organized cellulose microfibrils was discovered, on the surface of which spherical nanoparticles were visualized. Spherical nanoparticles with a diameter of 20–50 nm were isolated using size exclusion chromatography from an aqueous extract of differentiating xylem of Norway spruce and visualized by SEM and AFM. The composition of isolated nanoparticles was determined by pyrolytic GC-MS, ¹H NMR spectroscopy, and nitrobenzene oxidation, followed by separation of the products by liquid chromatography. Lignin was detected in the isolated nanoparticles already at the stage of cell wall formation. The hypothesis about the intracellular synthesis of lignin was proposed based on the results obtained. Lignin in the form of a lignocarbohydrate complex is formed not in the cell wall, but inside the cell. The formation of lignin–carbohydrate complexes occurs in Golgi apparatus and vesicles, which discharged into the inner surface of the cell wall simultaneously with the deposition of cellulose microfibrils. A new model of the structure of secondary cell wall postulates the formation of cellulose microfibrils surrounded by lignin–carbohydrate spherical complexes having a carbohydrate shell and an aromatic core. Full article

Fruit softening in Carica papaya L. is a significant postharvest limitation, primarily driven by the dynamic remodeling of cell wall polysaccharides. In this study, we conducted a genome-wide identification and in silico characterization of gene families involved in cell wall assembly and disassembly in papaya. A total of 181 genes were identified and classified into metabolic pathways: hemicellulose (58), pectin (69), extensin (24), expansin (13), and cellulose (17). These genes encode 176 predicted proteins, ranging in size from 100 to 1093 amino acids, featuring family-specific catalytic domains, including glycosyl hydrolases, transferases, and serine/threonine kinases. Phylogenetic analyses revealed strong conservation within the expansin-A and pectin polygalacturonase subfamilies, while hemicellulose-related XTH genes exhibited significant diversification. Experimental validation of nine XTH members confirmed this diversification, with amplicons ranging from 322 to 1370 bp, consistent with computational predictions. Notably, CpXTH1 and CpXTH32 produced bands of approximately 1200 and 1400 bp, respectively. These findings underscore the complexity of papaya cell wall gene families and provide a molecular framework for understanding fruit softening. Given that postharvest losses of papaya in Mexico exceed 34.7% of production (approximately 150,000 tons annually), our results offer valuable genomic resources for biotechnological strategies aimed at extending shelf life and reducing economic losses. Full article

Callus induction is the foundation for large-scale and rapid plant propagation, and explant age is a key factor affecting callus induction efficiency and in vitro culture outcomes. Pedicels are the main explants for Agapanthus praecox tissue culture. This study analyzed three pedicel developmental stages (S1: immature, S2: semi-mature, S3: mature) and their induced calli (C1, C2, C3). We integrated transcriptomics, metabolomics (LC-MS/GC-MS), quantitative real-time PCR (qRT-PCR), and weighted gene co-expression network analysis (WGCNA) to clarify the physiological and molecular mechanisms of pedicel regenerative potential. Results showed that S2 exhibited the highest callus induction rate, while C2 showed superior proliferation coefficients and regenerative potential. In pedicel samples, differentially expressed genes were significantly enriched in the MAPK signaling pathway and plant hormone signal transduction pathway, while differentially accumulated metabolites were linked to energy metabolism, amino acid/nucleotide metabolism, and stress responses. Key metabolites (e.g., carbohydrates, amino acids, thidiazuron, and β-chlorogenin) played specific roles in maintaining the meristematic capacity of pedicels. qRT-PCR further confirmed that S2 maintained balanced endogenous hormone signaling and proper cell wall modification. Furthermore, WGCNA identified a key module associated with oxidative stress responses along with S2. Overall, the regenerative potential of pedicel is mediated by the balanced hormone signal transduction, metabolic reprogramming, and epigenetic regulation in A. praecox. Full article

Citrus species develop fruits through both sexual reproduction and parthenocarpy, following a growth pattern with an initial exponential phase dominated by cell division in the ovary wall, followed by a linear phase driven by cell expansion in juice vesicles. Sustained carbohydrate supply is essential to support the metabolic energy required for these processes, which are tightly regulated by hormonal signaling pathways involving gibberellins (GAs), auxins (IAA), cytokinins, and abscisic acid (ABA). Recent studies across cultivars have identified genes associated with hormone biosynthesis, carbohydrate metabolism, cell cycle regulation, and abscission in ovule and pericarp tissues. Manipulation of these hormones through targeted treatments and cultural practices has shown potential to enhance fruit set and growth. Notably, exogenous GA₃ application promotes fruit set in parthenocarpic cultivars by upregulating GA20ox2/GA3ox and CYCA1.1, whereas synthetic auxins enhance fruit enlargement by improving assimilate partitioning and water uptake. Optimizing such treatments, however, requires a comprehensive understanding of physiological, environmental, and agronomic factors influencing fruit development. This review summarizes recent advances in hormonal and molecular regulation of citrus fruit set and developments, assesses applied strategies to improve productivity, and identifies current knowledge gaps needed to refine biotechnological and management aimed at enhancing both yield and fruit quality. Full article

Comparative omics analysis offers one of the most direct and effective approaches to gain novel insights into crop traits, facilitating candidate gene identification and crop improvement. Verticillium dahliae causes one of the most globally devastating crop diseases, the Verticillium wilt (VW). However, comparative transcriptome resources regarding VW resistance remain scarce in a major host species potato. To address this knowledge gap, we provide a comprehensive comparative RNA-seq analysis of VW resistance between a VW-resistant and -susceptible potato cultivar (LS8 and SP, respectively). VW inoculation induced dramatic transcriptomic changes, resulting in 14,310 differentially expressed genes (DEGs) in LS8 and 21,739 DEGs in SP. With the time-series analysis, we disentangled the VW-associated transcriptomic responses from those reflected LS8-SP cultivar differences. Particularly, LS8 featured a rapid response of phytohormone salicylic acid and defense-related specialized metabolites at 1 day post inoculation (dpi), followed by large-scale metabolic reprogramming, including carbohydrate and choline metabolism and enhanced biosynthesis of secondary cell wall components (e.g., hemicellulose, xylan, cuticle, suberin, and wax). Furthermore, we identified highly expressed VW-responsive potato phenylalanine ammonia-lyase genes (StPALs) and revealed the higher PAL activities in LS8 associated with VW resistance. Overall, our results provide the first transcriptomic insights into VW resistance in potato and new candidate genes regarding VW resistance. Full article

Fruit cracking in jujube is a major constraint on the sustainable development of the jujube industry. In this study, 60 mg L⁻¹ of 6-Benzylaminopurine (6-BA) was foliar-sprayed at the early fruit stage. Fruit cracking incidence was recorded during the green and white fruit periods, and these observations were integrated with transcriptomic and metabolomic analyses to explore the potential mechanisms by which 6-BA influences fruit cracking. The results showed that the fruit cracking in the treatment groups was 53% and 18% of that in the control group during the green period and the white period, respectively. In jujube peel, catalase (CAT) activity was significantly increased in the treated peel during both periods. In the peel metabolites, compounds belonging to the cytokinin (CTK) category exhibited significant accumulation in both periods. Transcriptomic analysis showed that differentially expressed genes (DEGs) were enriched in pathways related to starch and sucrose metabolism, plant hormone signal transduction, and cellular polysaccharide metabolism. These findings suggest that 6-BA treatment may alleviate jujube fruit cracking by enhancing antioxidant capacity, modulating hormone homeostasis, and upregulating genes associated with carbohydrate and cell wall metabolism. Full article

Watercore disease, a physiological disorder in pineapple (Ananas comosus), manifests during late fruit development. Affected fruits develop water-soaked flesh and reduced storability. (1) Background: To explore underlying molecular mechanisms, comparative proteomic profiling was conducted in this study. (2) Methods: Data-independent acquisition (DIA) strategy was employed for comparative analysis between the resistant germplasm “35-1” and the susceptible germplasm “29-3”, as well as between the healthy and diseased “Paris”. (3) Results: Resistant (“35-1”) versus susceptible (“29-3”) germplasm analysis revealed differentially expressed proteins (DEPs) and unique proteins (SEPs) enriched in cell walls, secretory vesicles, and apoplast, functioning in cell wall loosening, hormone response, isoflavonoid biosynthesis, and farnesyl diphosphate biosynthesis. Healthy versus diseased “Paris” pulp analysis showed DEPs/SEPs enrichment in ribosomal small subunit biogenesis. These proteins form a central regulatory network potentially orchestrating tRNA synthesis, tubulin biosynthesis, and other carbohydrate metabolism. Partial protein overlap occurred in germplasm- and disease-derived differences. Resistant germplasm (“35-1”) and healthy “Paris” accumulated stress-responsive/resistant proteins and cell wall-modifying enzymes (e.g., phenylalanine ammonia-lyase, raffinose synthase, expansins, and mannan hydrolase). Susceptible germplasm (“29-3”) and diseased “Paris” exhibited prominent stress-responsive protein accumulation, such as alcohol dehydrogenase, 1-aminocyclopropane-1-carboxylate oxidase, and hypoxia-induced protein. (4) Conclusions: This comparative proteomics study identifies pineapple watercore resistance/susceptibility-associated proteins, providing a molecular basis for resistant germplasm development and disorder control. Full article

Brassica napus is a key oilseed crop with potential for cultivation in contaminated soils. However, the molecular mechanisms underlying chromium (Cr) toxicity and tolerance are not well-defined. This study aimed to elucidate these mechanisms by analyzing two contrasting cultivars, ZS758 and ZD622, under 50 μM Cr stress using a hydroponic experiment for physiological assessments, transcriptomics, and metabolomics. Cr exposure significantly increased tissue Cr content and severely inhibited plant growth, photosynthesis, and mineral nutrient uptake. Multi-omics analysis revealed extensive transcriptional and metabolic reprogramming. Specifically, we identified 15,882 and 13,371 differentially expressed genes (DEGs) and 256 and 136 differentially expressed metabolites (DEMs) identified in ZS758 and ZD622, respectively. These changes were primarily enriched in carbohydrate and amino acid metabolism pathways. The tolerant cultivar ZS758 exhibited more robust activation of defense-related pathways, including cell wall biosynthesis, hormone signaling, and transporter activity. Our integrative analysis reveals that Cr tolerance in rapeseed associated with cultivar-specific physiological and molecular adaptations. These insights provide potential targets and pathways for developing Cr-resistant varieties for sustainable agriculture in contaminated environments. Full article

Anaerobic fungi (phylum Neocallimastigomycota) play a crucial role in degrading forages and fibrous foods in the gastrointestinal tract of mammalian herbivores, particularly ruminants. Currently, they are classified into twenty-two genera; however, recent research suggests the occurrence of several novel taxa that require further characterization. Anaerobic rumen fungi play a pivotal role in lignocellulose degradation due to their unique enzymatic capabilities. This review explores the enzymatic systems of rumen anaerobic fungi, highlighting their ability to produce a diverse array of carbohydrate-active enzymes (CAZymes), such as cellulases, hemicellulases, and pectinases. These enzymes facilitate the breakdown of complex plant polymers, making anaerobic fungi essential contributors to fiber degradation in the rumen ecosystem and valuable resources for biotechnological applications. This review summarizes the structural and functional diversity of fungal CAZymes, and the mechanical disruption of plant cell walls by fungal rhizoidal networks is discussed, showcasing the ability of fungi to enhance substrate accessibility and facilitate microbial colonization. Recent studies using genomic, transcriptomic, and biochemical approaches have uncovered several novel CAZymes in anaerobic fungi, including multifunctional xylanases, β-glucosidases, and esterases. These findings highlight the continued expansion of fungal enzyme repertoires and their potential for biotechnology and feed applications. Continued research in this field will enhance our understanding of microbial ecology and enzyme function, paving the way for applications that address global challenges in energy, food security, and environmental sustainability. Full article

Background/Objectives Plant lectins have emerged as potential antifungal molecules, where the carbohydrate recognition domain (CRD) is possibly the main mode of action of these proteins. Previously, we saw that the lectin extracted from the seeds of Dioclea violacea (DVL) has anti-candida activity against Candida krusei cells by acting to inhibit ergosterol biosynthesis, cell wall deformation, and deregulation of the redox system. Methods We have now confirmed this anti-candida activity by proteomic analysis, with the expression of proteins that show us how C. krusei cells respond to this treatment. Results A total of 395 proteins were identified: 142 proteins exclusively found in untreated C. krusei cells and 245 proteins exclusive to DVL-treated cells. Eight proteins were detected in both conditions. Six displayed positive accumulation (fold change > 1.5), one exhibited negative accumulation (fold change < 0.5). We observed the expression of proteins related to cell wall remodeling; alteration of energy metabolism, suggesting a metabolic adaptation to stress; oxidative stress was responded to through the expression of proteins with antioxidant action, in addition to identifying multidrug transport proteins that are often involved in the process of antifungal resistance and sterol transport to the membrane. Conclusions Our results show the complexity of adaptive responses of C. krusei cells to treatment with DVL, elucidating new mechanisms of resistance and paving the way for the development of more effective and innovative antifungal therapies. Full article

Light intensity strongly influences the morphological development and photoprotective responses of in vitro plantlets, yet the optimal conditions for hydrangea remain undefined. This study investigated the effects of five light intensity gradients (TrA: 80–120 lux, TrB: 380–480 lux, TrC: 1500–1800 lux, TrD: 3800–4000 lux, TrE: 6000–6400 lux) on Hydrangea macrophylla ‘Qingtian’ plantlets. Plantlets exhibited optimal growth at TrB, showing maximal biomass, leaf expansion, chlorophyll content, and root activity, accompanied by low antioxidant enzyme activities and soluble sugar levels. Nutrient accumulation was greater under low light than under high light conditions. Transcriptome analysis of treatments (TrB and TrE) with marked phenotypic differences revealed 7119 differentially expressed genes (DEGs). Of these, 4582 genes were up-regulated and 2537 were down-regulated. The up-regulated genes were significantly enriched in pathways related to cell walls, the microtubule cytoskeleton, and developmental processes, which are involved in the plant growth and development process, such as photosynthesis, nutrient ion transport and regulation, as well as plant hormone responses and transport; whereas the down-regulated genes were significantly enriched in pathways related to carbohydrate metabolism, oxidoreductase activity, and glutathione metabolism, suggesting that high light stress impairs growth by disrupting carbon and antioxidant processes. These results demonstrated that 380–480 lux is the optimal light intensity for ‘Qingtian’ Hydrangea macrophylla in vitro plantlets. This study provides a foundation for optimizing culture conditions and offers new insights into the molecular regulation of light-responsive genes. Full article

Fungal two-component signaling systems comprise histidine kinases (HKs), phosphotransfer intermediates, and response regulators. HKs are classified into eleven groups based on domain architecture; however, Group XI members in Botrytis cinerea remain uncharacterized. In this study, we investigated the functions of two Group XI histidine kinase genes, BcHK71 and BcHK67, in B. cinerea via gene replacement. Phenotypic analysis revealed that BcHK71 and BcHK67 regulate conidiation, infection structures formation, and glycerol synthesis. Notably, BcHK71 maintained cell wall integrity. Both genes also modulated expression of high osmolarity glycerol mitogen-activated protein kinase (HOG-MARK) signaling pathway components (BcYpd1, BcSkn7, BcBos4), while BcHK67 uniquely upregulated BcBrrg1 and enhanced BcHog1 phosphorylation. Transcriptomics analysis further indicated that BcHK71 and BcHK67 participated in pathways related to carbohydrate and lipid transport, metabolism and secondary metabolite biosynthesis. Disruption of these processes reduced pathogenicity and altered fungicide sensitivity in B. cinerea, with the ΔBcHK71 mutant exhibiting more severe pronounced defects. Collectively, our findings underscore the critical roles of BcHK71 and BcHK67 in fungal development and pathogenicity, highlighting their potential as novel targets for controlling fungal diseases and managing fungicide resistance. Full article

Piriformospora indica, a broad-spectrum plant growth-promoting fungus, has been successfully applied in blueberry (Vaccinium corymbosum L.). In this study, through an integrated transcriptomic and biochemical analyses, we investigated the effects of P. indica colonization on blueberry root growth under long-term tap water (EC ≈ 1500 μs/cm) irrigation. Comparative transcriptomic analysis revealed that P. indica colonization greatly influenced the expression of genes involved in RNA biosynthesis, solute transport, response to external stimuli, phytohormone action, carbohydrate metabolism, cell wall organization, and secondary metabolism pathways. Consistently, the fungal colonization significantly improved the nutrient absorption ability, and increased the contents of sucrose, starch, trehalose, total phenolic, total flavonoids, and indole-3-acetic acid (IAA), while suppressing the accumulations of jasmonic acid (JA), abscisic acid (ABA), 1-aminocyclopropane-1-carboxylic acid (ACC), and strigolactone (SL) in blueberry roots. Quantitative real-time PCR verification also confirmed the fungal influences on genes associated with these pathways/parameters, such as auxin homoeostasis-associated WAT1, cell wall metabolism-related EXP, phenylpropanoid biosynthesis-related PAL and CHS, carotenoid degradation-related CCD8, transportation-related CNGC, trehalose metabolism-related TPP, and so on. Our study demonstrated that P. indica improved blueberry adaptability to mild salt stress by synergistically regulating cell wall metabolism, secondary metabolism, stress responses, hormone homeostasis, sugar and mineral element transportation, and so on. Full article

Sulfiting agents are common preservatives in the food and beverage industry to inhibit spoilage microorganisms. Sulfite produced by the dissolution of sulfur dioxide (SO₂) in water is used as a microbial inhibitor and antioxidant during winemaking. Thus, sulfite resistance is a desirable trait for wine yeasts. However, consumer health concerns regarding SO₂ exposure require a better understanding of the molecular basis of sulfite resistance/response. In this study, we have developed a highly SO₂-stress-resistant Saccharomyces cerevisiae strain (F3) using evolutionary engineering by repeated batch selection at gradually increased potassium metabisulfite (K₂S₂O₅) levels. F3 was resistant to 1.1 mM K₂S₂O₅ stress, which was strongly inhibitory to the reference strain, and cross-resistant to oxidative, heat, and freeze–thaw stresses. F3 also had enhanced cell wall integrity and altered carbon metabolism, indicating its potential for industrial applications, including winemaking. Comparative whole genome sequencing revealed point mutations in SSU1 and FZF1 that are related to SO₂ transport; ATG14, related to autophagy; and other genes involved in vacuolar protein sorting. Comparative transcriptomic analysis showed significant upregulation of SSU1 and differential expression of genes related to transport and carbohydrate metabolism. These findings may shed light on the molecular mechanisms contributing to SO₂ resistance and industrial robustness in S. cerevisiae. Full article

Methane (CH₄) produced by methanogenic archaea during the rumen fermentation of feed carbohydrates leads to global warming and total energy loss. This study aims to compare the accuracy of multiple linear regression (MLR) models and backpropagation neural network (BPNN) in predicting ruminal CH₄ production of the carbohydrate (Carbs) components of the Cornell Net Carbohydrate and Protein System (CNCPS) in mixed rations of beef cattle with different concentrate-to-forage (C/F) ratios. Two datasets were established using the in vitro fermentation method of Menke and Steingass. One of the datasets contained 60 mixed rations with C/F ratios of 30:70, 40:60, 50:50, 60:40, 70:30, 80:20, and 90:10, respectively, which were used to develop CH₄ prediction models. Another dataset included 10 mixed rations with the same C/F ratios, which were used to validate and compare the accuracy of the prediction models. Results indicated that there was a significant multiple regression relationship between CH₄ production and the Carbs-components (CA (sugars), CB₁ (starch and pectin), CB₂ (available cell wall), CC (unavailable cell wall)) of CNCPS (r² = 0.91, p < 0.0001). An optimal BPNN model with 2 hidden-layer neuron nodes was established with the same variables (r² = 0.93, p < 0.0001). The findings demonstrated that both MLR and BPNN models (p < 0.0001) were suitable for predicting CH₄ production using the Carbs components (CA, CB₁, CB₂, CC) of CNCPS. However, compared with the MLR model, the BPNN model has a greater coefficient of determination (r²) value and concordance correlation coefficient (CCC), and a lower root mean square prediction error (RMSPE), demonstrating better prediction performance. Full article