Search Results (378)

Ferulic acid (FA) is one of the most abundant hydroxycinnamic acids found in plant cell walls. Its dehydrodimers play an important role in maintaining the structural rigidity of the plant cell wall. Ferulic acid esterases (FAEs) act as debranching enzymes, cleaving the ester bond between FA and the substituted carbohydrate moieties in FA-containing polysaccharides in the plant cell wall. This enzymatic reaction facilitates the degradation of lignocellulosic materials and is crucial for the efficient utilization of biomass resources. This review focuses on the occurrence of ferulic acid in nature and its different forms and outlines the various classification systems of FAEs, their substrate specificity, and the synergistic interactions of these enzymes with other CAZymes. Additionally, it highlights the various methods that have been developed for detecting hydroxycinnamic acids and estimating the enzyme activity, as well as the versatile applications of ferulic acid. Full article

Sclerotinia sclerotiorum (S. sclerotiorum), a necrotrophic phytopathogen, causes sclerotinia stem rot (SSR) in many crops like oilseed rape, resulting in severe economic losses. Developing eco-friendly compound fungicides has become a critical research priority. This study explored the combination of sodium selenite and cuminic acid to screen for the optimal mixing ratio and investigate its inhibitory effects and mechanisms against S. sclerotiorum. The results demonstrated that synergistic effects were observed with a 1:3 combination ratio of sodium selenite to cuminic acid. After treatment with the selenium compound agent, ultrastructural observations revealed that the hyphae of S. sclerotiorum became severely shriveled, deformed, and twisted. The agent significantly reduced oxalic acid production and the activities of polymethylgalacturonide (PMG) and carboxymethylcellulose enzymes (Cx), while increasing the exocytosis of nucleic acids and proteins from the mycelium. Foliar application of the selenium compound agent significantly reduced lesion areas in rapeseed. Combined with the results of transcriptome sequencing, this study suggests that the compound agent effectively inhibits the growth of S. sclerotiorum by disrupting its membrane system, reducing the activity of cell wall-degrading enzymes, and suppressing protein synthesis, etc. This research provides a foundation for developing environmentally friendly and effective fungicides to control S. sclerotiorum. Full article

Aromatic compounds are vital in both natural and synthetic chemistry, and they are traditionally sourced from non-renewable petrochemicals. However, plant biomass, particularly lignin, offers a renewable alternative source of aromatic compounds. Lignin, a complex polymer found in plant cell walls, is the largest renewable source of aromatic compounds, though its degradation remains challenging. Lignin can be chemically degraded through oxidation, acid hydrolysis or solvolysis. As an alternative, microorganisms, including fungi, could offer a sustainable alternative for breaking down lignin. The aromatic compounds released from lignin, by either microbial, chemical or enzymatic degradation, can be used by microorganisms to produce valuable compounds. Fungi possess unique enzymes capable of converting aromatic compounds derived from lignin or other sources into chemical building blocks that can be used in several industries. However, their aromatic metabolic pathways are poorly studied compared to bacterial systems. In the past, only a handful of genes and enzymes involved in the aromatic metabolic pathways had been identified. Recent advances in genomics, proteomics, and metabolic engineering are helping to reveal these metabolic pathways and identify the involved genes. This review highlights recent progress in understanding fungal aromatic metabolism, focusing on how Aspergillus niger converts plant-derived aromatic compounds into potentially useful products and the versatility of aromatic metabolism within the Aspergillus genus. Addressing the current knowledge gaps in terms of fungal pathways could unlock their potential for use in sustainable technologies, promoting eco-friendly production of chemical building blocks from renewable resources or bioremediation. Full article

Gray mold disease, caused by the fungus Botrytis cinerea, affects a wide variety of plants. In this study, we conducted several in vitro tests and genomic analyses on three strains of this fungus (BcPgIs-1, BcPgIs-3, MIC) previously isolated from diseased pomegranate fruits, collected at two geographic locations in Mexico. Our goal was to identify possible differences among these strains. The development of the three strains in distinct culture media, the production of extracellular enzymes, and their effect on the progression of infection in pomegranate fruits were evaluated. The genomes were sequenced using the Illumina platform and analyzed with various bioinformatics tools. All strains possess genetic determinants for virulence and cell wall polymer degradation, but MIC exhibited the highest pectinolytic activity in vitro. This strain also produced sclerotia in a shorter time (7 days) in PDA medium. BcPgls-3 demonstrated the highest conidia production across all the culture media used. Both BcPgls-3 and MIC damaged all the pomegranate fruits 8 days after inoculation, while the BcPgls-1 required up to 9 days. Sequencing of the three strains yielded high-quality sequences, resulting in a total of 17 scaffolds and genomes that exceed 41 million bp, with a GC content of approximately 42%. Phylogenomic analysis indicated that the MIC strain is situated in a group separate from BcPgIs-1 and BcPgIs-3. BcPgIs-3 possesses more coding sequences, but MIC has more genes for CAZymes and peptidases. The three strains share 10,174 genes, while BcPgIs-3 and MIC share 851. These findings highlight the differences among the strains studied, which may reflect their adaptive capacities to their environment. Results contribute to our understanding of the biology of gray mold in pomegranates and could assist in developing more effective control strategies. Full article

This review presents information obtained over the past 10 years on the methods to control the widespread worldwide phytopathogen Pectobacterium carotovorum subsp. carotovorum (Pcc). This bacterium is among the ten most dangerous phytopathogens; it affects a wide range of cultivated plants: vegetables, ornamental and medicinal crops, both during vegetation and during the storage of fruits. Symptoms of Pcc damage include the wilting of plants, blackening of vessels on leaves, stems and petioles. At the flowering stage, the stem core gradually wilts and, starting from the root, the stem breaks and the plant dies. Pcc is a rod-shaped, non-capsule and endospore-forming facultative anaerobic Gram-negative bacterium with peritrichous flagellation. Pcc synthesizes bacteriocins—carocins. The main virulence factors of Pcc are the synthesis of N-acyl-homoserine lactone (AHL) and plant cell wall-degrading enzymes (PCWDEs) (pectinases, polygalacturonases, cellulases, and proteases). Diagnostic methods for this phytopathogen include polymerase chain reaction (PCR), loop-mediated isothermal amplification (LAMP), multilocus genotyping of strain-specific genes and detection of unique volatile organic compounds (VOCs). The main methods to control this microorganism include the use of various chemicals (acids, phenols, esters, salts, gases), plant extracts (from grasses, shrubs, trees, and algae), antagonistic bacteria (Bacillus, Pseudomonas, Streptomyces, and lactic acid bacteria), viruses (including a mixture of bacteriophages), and nanomaterials based on metals and chitosan. Full article

The genus Xanthomonas (family Xanthomonadaceae) comprises 39 validly published species and is associated with a broad host range, infecting hundreds of monocot and dicot plants worldwide. While many Xanthomonas species are notorious for causing leaf spot and blight diseases in major agricultural crops, less attention has been given to their impact on ornamental plants. In Hawaii and other key production regions, xanthomonads have posed persistent threats to popular ornamentals in the Araceae and Araliaceae families. This review synthesizes the evolving phylogenetic and taxonomic framework of Xanthomonas strains isolated from Araceae and Araliaceae, highlighting recent advances enabled by multilocus sequence analysis and whole genome sequencing. We discuss the reclassification of key pathovars, unresolved phylogenetic placements, and the challenges of pathovar delineation within these plant families. Additionally, we examine current knowledge of molecular determinants of pathogenicity, including gene clusters involved in exopolysaccharide and lipopolysaccharide biosynthesis, flagellar assembly, cell-wall-degrading enzymes, and secretion systems (types II, III, and VI). Comparative genomics and functional studies reveal that significant gaps remain in our understanding of the genetic basis of host adaptation and virulence in these xanthomonads. Addressing these knowledge gaps will be crucial for developing effective diagnostics and management strategies for bacterial diseases in ornamental crops. Full article

Microbial decomposition of persistent natural compounds such as phenolic lignin and polysaccharides in plant cell walls plays a crucial role in the global carbon cycle and underpins diverse biotechnological applications. Among microbial decomposers, fungi from the Ascomycota and Basidiomycota phyla have evolved specialized mechanisms for efficient lignocellulosic biomass degradation, employing extracellular enzymes and synergistic fungal consortia. Fungal coculture, defined as the controlled, axenic cultivation of multiple fungal species or strains in a single culture medium, is a promising strategy for industrial processes. This approach to biomass conversion offers potential for enhancing production of enzymes, biofuels, and other high-value bioproducts, while enabling investigation of ecological dynamics and metabolic pathways relevant to biorefinery operations. Lignocellulosic biomass conversion into fuels, energy, and biochemicals is central to the bioeconomy, integrating advanced biotechnology with sustainable resource use. Recent advancements in -omics technologies, including genomics, transcriptomics, and proteomics, have facilitated detailed analysis of fungal metabolism, uncovering novel secondary metabolites and enzymatic pathways activated under specific growth conditions. This review highlights the potential of fungal coculture systems to advance sustainable biomass conversion in alignment with circular bioeconomy goals. Full article

The fungus Alternaria alternata, which causes tobacco brown spot disease, poses a serious threat to the tobacco industry. Beneficial microorganisms and their secondary metabolites have emerged as a promising green strategy for disease management. This study recovered 16 endophytic bacterial strains from Mentha haplocalyx Briq., a therapeutic herb. The study revealed that strain B5, with an inhibition rate of 82.76%, exhibited the highest antifungal activity against A. alternata. This strain exhibited broad-spectrum antifungal activity, with inhibition rates ranging from 66.34% to 87.23%. Phylogenetic analysis of 16S rDNA and gyrA gene sequences identified it as Bacillus velezensis (GenBank: PV168970 and PV173738). Further characterization revealed that strain B5 can secrete cell wall-degrading enzymes, produce IAA, and synthesize siderophores. The growth of mycelium in A. alternata was greatly reduced by both the ethyl acetate extract and the filtered liquid from the sterile fermentation, resulting in marked morphological abnormalities. Multiple antifungal active substances were identified through liquid LC-MS analysis. Greenhouse experiments demonstrated that the B5 fermentation broth effectively suppressed the occurrence of tobacco brown spot disease, achieving a relative control efficacy of 60.66%, comparable to that of 10% difenoconazole water dispersible granule (WDG). Additionally, strain B5 enhances plant disease resistance by activating the activities of key defense enzymes. B. velezensis B5 serves as a safe alternative to chemical fungicides and is highly effective at controlling tobacco brown spot disease. Full article

The valorization of plant biomass is one of the main strategies for sustainable development. However, its use as energy, biofuels, fertilizers, value-added products, or even food is severely affected by the complexity of the plant cell wall. Therefore, the evaluation of fungi with high production of lignocellulolytic enzymes capable of efficiently degrading these substrates constitutes a viable, clean, and eco-friendly solution, allowing, for example, an increase in the digestibility and nutritional quality of alternative animal feed sources. For these reasons, the present study evaluated the ability of the mutant strain Trichodema viride M5-2 to improve the nutritional composition of the forage legumes Lablab purpureus and Mucuna pruriens through solid-state fermentation. Endo- and exoglucanase cellulolytic activity was assessed, as well as the effect of fermentation on the fiber’s physical properties and chemical composition. Molecular changes in the structure of plant fiber were analyzed using infrared spectroscopy. Increased production of the cellulolytic complex of the enzymes endoglucanase (3.29 IU/mL) and exoglucanase (0.64 IU/mL) was achieved in M. pruriens. The chemical composition showed an increase in true protein and a decrease in neutral fiber, hemicellulose, and cellulose, with a consequent improvement in nutritional quality. Fiber degradation was evident in the infrared spectrum with a significant decrease in the signals associated with cellulose and, to a lesser extent, with lignin. It can be concluded that the mutant strain T. viride M5-2 produced chemical, physical, and molecular changes in the fibrous and protein fractions of L. purpureus and M. pruriens through SSF, which improved their nutritional value as an alternative feed for animal nutrition. By promoting the use of this fungus, the nutritional quality of this source is increased through an effective and eco-friendly process, which contributes to mitigating the environmental impact of food production, in accordance with sustainability objectives and the need for more responsible agricultural practices. Full article

Actinidia arguta (A. arguta) is valued for its nutritional richness, but physiological fruit abscission severely limits production efficiency in elite cultivars. To unravel the molecular basis of this process, we compared two cultivars: abscission-prone ‘KL’ and abscission-resistant ‘JL’. During fruit development, ‘KL’ exhibited an earlier decline in auxin (AUX) levels within the fruit abscission zone (FAZ), coupled with persistently higher ethylene (ETH) concentrations and polygalacturonase (PG) activity compared to ‘JL’. Comparative transcriptomics identified abscission-related genes enriched in plant hormone signaling (AUX, ETH, ABA, JA, BR), starch/sucrose metabolism, and photosynthesis pathways. AUX signaling diverged predominantly during early development, while ETH, BR, and JA pathways varied across multiple stages. Exogenous applications of plant growth regulators (ethephon, 2,4-D, methyl jasmonate, and 2,4-epibrassinolide) and transient overexpression of key genes (AaETR1, AaERF035, AaPME68, AaPP2C27, AaMYC1, and AaPMEI10) validated their roles in modulating hormone crosstalk and cell wall remodeling. Overexpression of AaERF035 and AaPME68 likely accelerated abscission by enhancing ETH biosynthesis and pectin degradation, while AaPMEI10 and AaMYC1 potentially delayed abscission via suppression of cell wall-modifying enzymes. This study elucidates the hormonal and transcriptional networks governing fruit abscission in A. arguta, providing insights for targeted breeding and cultivation strategies to mitigate yield loss. Full article

Sustainable agricultural practices are essential for eradicating global hunger, especially in light of the growing world population. Utilizing natural antagonists, such as fungi and bacteria, to combat plant diseases, rather than relying solely on synthetic chemical pesticides, which pose significant risks to the environment and human health, is known as biocontrol. Microbial biological control agents (MBCAs) have proven effective against phytopathogens and are increasingly embraced in agricultural practices. MBCAs possess several beneficial traits, including antagonistic potential, rhizosphere competence, and the ability to produce lytic enzymes, antibiotics, and toxins. These biocontrol mechanisms directly target soil-borne pathogens or indirectly stimulate a plant-mediated resistance response. The effectiveness of MBCAs in managing plant diseases depends on various mechanisms, such as hyperparasitism, antibiosis, competition for nutrients or space, disruption of quorum-sensing signals, production of siderophores, generation of cell wall-degrading enzymes, and the induction and priming of plant resistance. Formulating effective biopesticides requires optimal conditions, including selecting effective strains, considering biosafety, appropriate storage methods, and ensuring a prolonged shelf life. Therefore, formulation is crucial in developing pesticide products, particularly concerning efficacy and production costs. However, several challenges must be addressed to ensure the successful application of biological control, including the shelf life of biopesticides, slower efficacy in pest management, inadequate awareness and understanding of biocontrol methods, regulatory registration for commercialization, and suitable agricultural applications. This review clarifies the principles of plant disease biocontrol, highlighting the mechanisms of action and functionality of MBCAs in biocontrol activities, the formulation of biopesticides derived from microorganisms, and the challenges and barriers associated with the development, registration, commercialization, and application of biopesticides. Full article

Pectin is a dynamic and complex polysaccharide that forms a substantial proportion of the primary plant cell wall and middle lamella of forage ingested by grazing ruminants. Pectin methylesterases (PMEs) are enzymes that belongs to the carbohydrate esterase family 8 (CE8) and catalyze the demethylesterification of pectin, a key polysaccharide in cell walls. Here we present the crystal structure of the catalytic domain of PmeC5 that is associated with a gene from Butyrivibrio fibrisolvens D1^T that encodes a large secreted pectinesterase family protein (2089 aa) determined to a resolution of 1.33 Å. Protein in silico modelling of the secreted pectinesterase confirmed the presence of an additional pectate lyase (PL9) and adhesin-like domains. The structure of PmeC5 was the characteristic right-handed parallel β-helical topology and active site residues of Asp231, Asp253, and Arg326 typical of the enzyme class. PmeC5 is a large modular enzyme that is characteristic of rumen B. fibrisolvens megaplasmids and plays a central role in degrading plant cell wall components and releasing methanol in the rumen environment. Such secreted PMEs are significant contributors to plant fiber digestion and methane production, making them attractive targets for both methane mitigation strategies and livestock productivity enhancement. Full article

Hydroxyproline O-arabinosyltransferase (HPAT), a critical enzyme in plant glycosylation pathways, catalyzes the transfer of arabinose to the hydroxyl group of hydroxyproline residues. This enzyme contains a canonical GT95 glycosyltransferase, a structural hallmark of this carbohydrate-active enzyme family. HPAT mediates arabinosylation of diverse cellular targets, including cell wall extension and small signaling peptides. Emerging evidence has shown that HPAT orthologs regulate plant development and symbiotic interactions through post-translational modification of CLV1/LRR Extracellular (CLE) peptides. Although the molecular functions of HPAT genes have been characterized in model plants such as Arabidopsis thaliana and Lotus japonicus, their roles remain unexplored in Zea mays L. In this study, we used ZmHPAT2 homozygous mutants to explore the function of the maize HPAT gene. Sequence analysis identified a N-terminal signal peptide targeting the Golgi apparatus and promoter elements responsive to AM fungal colonization. Phenotypic analysis revealed its negative regulatory role: zmhpat2 promotes vegetative growth (increased plant height and accelerated flowering) and enhances AM symbiosis (increased colonization rate). Mechanistic studies demonstrated that ZmHPAT2 possesses dual regulatory functions—the activation of auxin signaling and repression of ZmMYB1-mediated arbuscular degradation pathways. In addition, overexpression of ZmHPAT2 in Lotus japonicus inhibits growth (reduced plant height) and impairs symbiotic interactions. Our findings establish ZmHPAT2 as a critical node to regulate auxin and symbiotic signaling, providing novel insights into plant glycosylation-mediated development. This work not only advances our understanding of maize growth regulation but also identifies potential targets for crop improvement through arabinosylation pathway manipulation. Full article

Peelability, a crucial commercial trait for fresh-eating citrus, has received limited research attention regarding its underlying mechanisms. This study investigated three late-maturing citrus cultivars, namely ‘Qingjian’ (QJ), ‘Mingrijian’ (MRJ), and ‘Chunjian’ (CJ), analyzing their peelability development using texture analysis and exploring the physiological and biochemical factors influencing peeling difficulty. The results showed that peelability improved with fruit maturation, reaching its peak at full ripeness, with the following order of peeling difficulty: QJ (hardest) > MRJ (intermediate) > CJ (easiest). At full maturity, QJ (the most difficult to peel) exhibited more regularly shaped peel cells with fewer intercellular spaces, lower intracellular organic matter accumulation, and higher levels of cell wall polysaccharides, calcium (Ca), and abscisic acid (ABA). These characteristics may be linked to the lower relative expression of soluble sugar (TS)-related genes (CCR4A, SPP1) and the titratable acid (TA)-related gene (CsCit1), as well as the higher relative expression of ABA biosynthesis genes (NCED1, NCED2). Correlation analyses demonstrated that citrus peel firmness and adhesion strength are significantly associated with multiple growth and developmental characteristics, including fruit morphometric parameters, peel cellular architecture, intracellular organic compound content, cell wall polysaccharide levels and related degradative enzyme activities, calcium concentrations, and endogenous phytohormone profiles. These findings provide valuable insights for studying peelability mechanisms and improving fruit quality in citrus breeding. Full article

Grapevine trunk diseases (GTDs) are widespread worldwide, causing serious economic losses to the vitiviniculture industry. The etiology of the complex pathogenic mycobiome associated with this group of diseases is critical to implementing appropriate management strategies. Diseased grapevines exhibiting typical GTD symptoms were collected from vineyards in different provinces of Cyprus, resulting in 19 pycnidial isolates. A subsequent multilocus sequence analysis of six genetic loci (ITS, LSU, SSU, b-tub, tef1-a, and rpb2) identified them as Kalmusia variispora, and twelve representative isolates are included in the phylogenetic analyses. According to pathogenicity trials on two-year-old potted vines (cv. Mavro), all tested isolates were pathogenic, exhibiting light to dark brown discoloration and lesions of varying levels, ranging from 4 to 12.3 cm long. The capacity of K. variispora isolates to produce cell-wall-degrading exoenzymes was qualitatively estimated on solid media. Cellulase, pectinase, and laccase production were evident for all the tested isolates, except isolate CBS 151329, where the latter enzyme was undetected. The severity of the symptoms was consistent with the laccase-producing capacity. The present study confirmed the association of K. variispora with grapevines as a pathogen and represents the first description of this ascomycete as a GTD causal agent in Cyprus. This highly virulent species may play a significant role in the GTD complex, and its biological cycle and epidemiology should be further investigated. Full article