Search Results (75)

Monascus purpureus is a filamentous fungus renowned for producing bioactive secondary metabolites, including lovastatin and azaphilone pigments. Lovastatin is valued for its cholesterol-lowering properties and cardiovascular benefits, while Monascus pigments exhibit anti-cancer, anti-inflammatory, and antimicrobial activities, underscoring their pharmaceutical and biotechnological relevance. This study evaluated the impact of carbohydrate-derived elicitors—mannan oligosaccharides, oligoguluronate, and oligomannuronate—on the enhancement of pigment and lovastatin production in M. purpureus C322 under submerged fermentation. Elicitors were added at 48 h in shake flasks and 24 h in 2.5 L stirred-tank fermenters. All treatments increased the production of yellow, orange, and red pigments and lovastatin compared to the control, with higher titres upon scale-up. OG led to the highest orange pigment yield (1.2 AU/g CDW in flasks; 1.67 AU/g CDW in fermenters), representing 2.3- and 3.0-fold increases. OM yielded the highest yellow and red pigments (1.24 and 1.35 AU/g CDW in flasks; 1.58 and 1.80 AU/g CDW in fermenters) and the highest lovastatin levels (10.46 and 12.6 mg/g CDW), corresponding to 2.03–3.03-fold improvements. These results highlight the potential of carbohydrate elicitors to stimulate metabolite biosynthesis and facilitate scalable optimisation of fungal fermentation. Full article

The effects of a fungal elicitor from Trichothecium roseum on signal pathways of salicylic acid (SA), jasmonic acid (JA), and Ca²⁺ in potato tubers were investigated. The results showed that fungal elicitor treatment effectively inhibited the lesion diameter of Fusarium sulphureum in vivo, which was 17.5% lower than that of the control. In addition, fungal elicitor treatment triggered an increase in O₂⁻ production and H₂O₂ content. The fungal elicitor enhanced the activities and gene expression levels of isochorismate synthase (ICS), phenylalanine ammonia lyase (PAL), allene oxide cyclase (AOC), allene oxide synthase (AOS), lipoxygenase (LOX), and Ca²⁺-ATPase. Furthermore, the fungal elicitor promoted an increase in calmodulin (CaM) content. Protective enzymes (dismutase (SOD), catalase (CAT), polyphenol oxidase (PPO), chitinase (CHI), and β-1,3-glucanase (Glu)) and disease-resistance-related genes (PR1, PR2, and PDF1.2) were induced to be upregulated by elicitor treatment. These results indicated that the fungal elicitor induced disease resistance by accelerating the accumulation of reactive oxygen species (ROS), activating SA, JA, and Ca²⁺ signaling, and upregulating resistance genes. The results of this study revealed the molecular mechanism of fungal elicitor-induced resistance in the potato, which provides a theoretical basis for the mining of new, safe, and efficient elicitor-sourced antifungal agents and is of great importance for the effective control of potato dry rot disease. Full article

Chicory (Cichorium intybus L.) roots are valued in medicine for their potential health benefits. Producing callus from chicory roots through tissue culture technology can streamline bioactive metabolites production and ensure a sustainable supply chain. The current study explored the impact of plant growth regulators (PGRs) and light conditions on the characteristics of callus induced from C. intybus root explants. The effect of fungal elicitors [yeast extract (YE), Fusarium oxysporum, and Aspergillus niger] on bioactive metabolite production from root-derived callus was investigated. Callus color varied notably between a 16/8 h light/dark cycle and complete dark, with differences in texture based on PGR concentrations and light conditions. High weights of callus formed were generally recorded under the 16/8 h light/dark cycle. Low concentrations of YE (1 g/L) and F. oxysporum (0.25 g/L) enhanced callus biomass fresh weight, while high concentrations of A. niger (1 g/L) improved callus dry matter significantly. The content and productivity of total phenolic were maximized at 1 g/L of YE and 1 g/L of F. oxysporum. Callus cultures elicited with a higher level of A. niger recorded the higher values of total flavonoid production. High-performance liquid chromatography (HPLC) analysis revealed significant variations in chlorogenic acid, catechin, and caffeic acid levels among the different elicited cultures. A. niger at 1 g/L notably increased chlorogenic acid content, while catechin levels were enhanced by specific concentrations of YE. Catalase (CAT) activity was significantly affected by different elicitors, while only the higher level of F. oxysporum and A. niger showed a significant increase in peroxidase (POD) activity. DPPH scavenging activity was elevated by all fungal elicitors. Principal Component Analysis delineated distinct variations in callus traits in response to different elicitors, with specific treatments showcasing enhanced biomass production, bioactive compound accumulation, and antioxidant activities. Through meticulous experimentation, this study paves the way for enhancing chicory root-derived products, ensuring sustainable production and potent bioactivity. Full article

Rice blast disease is a major threat to rice yields. Sustainable control relies on resistant varieties, where plant immunity is triggered by pattern recognition receptors like receptor-like proteins (RLPs). The rice RLP chitin-elicitor binding protin (CEBiP) recognizes fungal chitin and confers blast resistance to pathogen Magnaporthe oryzae. However, understanding of the broader signaling and metabolomic pathways associated with CEBiP activation remains limited. Here, we performed an integrated transcriptomic and metabolomic analysis of the rice Zhonghua 11 genotype and CEBiP knockout plants. Both plants were infected with M. oryzae, and infected leaves were harvested at 24, 48, and 72 hpi for RNA sequencing and Liquid Chromatography-Tandem Mass Spectrometry analysis. Transcriptomics identified a total of 655 genes that were differentially regulated upon knockout of CEBiP; they were mainly related to diterpenoid/phenylpropanoid biosynthesis, nitrogen metabolism, the mitogen-activated protein kinasesignaling pathway, plant–pathogen interaction, and plant hormone signal transduction. The presence of a large number of pathogenesis-related protein 1 family genes indicates the key role of salicylic acid (SA) in CEBiP immunity. Metabolomics detected a total of 962 differentially accumulated metabolites and highlights the roles of caffeine and glutathione metabolism in CEBiP-mediated immunity. Since caffeine and glutathione metabolism can regulate SA signaling, we propose that SA signaling plays a central role in the CEBiP immune function. Full article

Tomato is among the most widely traded and consumed vegetables throughout the world; however, it is highly vulnerable to infection by the fungus Alternaria alternata. Fungal elicitors such as chitin oligomers have been shown to trigger the plant’s immune response, protecting the plant against pathogen attacks. Signaling molecules such as ethylene (Et), jasmonic acid (JA), and salicylic acid (SA) are key players in this immune response; however, it is unknown whether fungal chitin oligomers induce the production of these molecules. This study aimed to assess the effect of chitin oligomers isolated from the biomass of the A. alternata on the production of Et, JA, and SA in tomato fruits, as well as the expression of genes encoding transcription factors related with the signaling of Et (SlERF1), JA (SlMYC2), and SA (SlWRKY31). Low-molecular weight chitin oligomers were obtained from A. alternata. The results showed that SlMYC2 involved in JA signaling and production was the first gene induced by chitin oligomers 0.5 h post treatment. Furthermore, after 6 h, a second increase in gene expression was observed. However, SlERF1 involved in Et signaling increased 1 h post treatment and was highly correlated with high expression levels of the SlMYC2 gene, suggesting a strong relationship between Et and JA signaling. The most significant increase in gene expression was observed in SlWRKY31 involved in SA signaling 6 h post treatment with chitin oligomers, which showed a high correlation with Et production. It is concluded that the chitin oligomers of A. alternata elicit an early response in the production of Et, JA, and SA in tomato fruit, which play an important role as signaling molecules in the activation of plant defense mechanisms. Full article

The best known Microdochium spp. are important pathogens of small-grain cereals and/or endophytes of diverse monocot hosts. This study is the first report of M. majus isolated from asymptomatic grapevine tissues. It was hypothesised that this M. majus strain, CBS 152328, was an endophyte and an antagonist of some fungal pathogens of grapevine. Microscopic examinations revealed that this strain was a necrotrophic mycoparasite of Botrytis cinerea. This was demonstrated in the confrontation zones of dual cultures of M. majus and B. cinerea, and also on the surface of co-inoculated grape leaf discs and germinated wheat grains. Pathogenicity tests indicated that M. majus can colonise both grape leaf discs and germinated wheat, but it only damaged wheat. When co-inoculated with B. cinerea onto grape leaf discs, the M. majus strain CBS 152328 suppressed its mycohost on grape tissues and prevented leaf necrosis caused by B. cinerea. In addition to the parasitism, M. majus also showed mild antibiosis against B. cinerea, as well as a defence elicitor effect on grape leaf discs. This work is the first report of the mycoparasitic behaviour of M. majus, in addition to its first isolation from a dicot host. Full article

Pine wilt disease, caused by the pine wood nematode (Bursaphelenchus xylophilus), poses a serious threat to forests in Korea. In this study, we investigated the resistance of Pinus densiflora to B. xylophilus following treatment with a fungal elicitor derived from Penicillium chrysogenum through trunk injection and soil drenching. Soil drenching with the fungal elicitor led to increased accumulation of two key defensive compounds: pinosylvin monomethyl ether (PME) and dihydropinosylvin monomethyl ether (DPME) in the needles. In untreated control plants inoculated with B. xylophilus, 67.9% died within five months, whereas only 33.3% of plants pretreated with the elicitor succumbed. Trunk injection of the fungal elicitor also significantly enhanced PME production. The PME concentration in the needles peaked at 155.4 µg/g dry weight (DW) four weeks post-elicitor injection. To assess the impact of elicitor treatment on nematode resistance, we monitored the downward movement of B. xylophilus in plants two months post-injection of fungal elicitor. Nematodes were introduced at the upper internodal segments of branches, and their mobility to the lower segments was measured. In elicitor-treated trees, the movement and population of B. xylophilus were significantly reduced, highlighting the effectiveness of the treatment. These results demonstrate that fungal elicitor treatments, through soil drenching or trunk injection, can enhance the resistance of P. densiflora to B. xylophilus. This eco-friendly approach offers a promising strategy for managing pine wilt disease in susceptible pine species. Full article

Finding safe and reliable alternatives to fungicides is currently one of the biggest challenges in agriculture. In this regard, this experiment investigated the effectiveness of different elicitors, botanical extracts and essential oils to control grey mold (Botrytis cinerea) and powdery mildew (Podosphaera aphanis) on strawberry plants. This trial was conducted in field conditions under a plastic tunnel with strawberry plants ‘Elsanta’. A first group of strawberry plants was treated before flowering with elicitors [acibenzolar-S-Methyl–(BTH), chitosan], botanical extracts (seaweed extract, alfalfa hydrolysate) and essential oils (thyme and juniper), and grey mold incidence on flowers was evaluated (Experiment 1). Furthermore, a second group of plants was treated before (Experiment 2) and after (Experiment 3) controlled inoculation with P. aphanis. The results indicated that the incidence of flower infected by B. cinerea was reduced by approximately 50% with thyme and juniper essential oils’ applications compared to the untreated control, with no significant difference observed compared to the commercial fungicide penconazole (positive control). As a consequence, the final yield of essential-oil-treated plants was +27% higher than that of non-treated plants. No significant differences emerged for other tested products against grey mold. However, gene expression analysis showed an up-regulation (>2 ÷ 5 folds as compared to control 4 days after application) of FaEDS1, FaLOX and PR gene expression (FaPR1, FaPR5, FaPR10) in leaves treated with BTH. The other natural substances tested also induced defense-related genes, albeit at a lower level than BTH. In Experiment 2, all treatments applied prior to inoculation significantly reduced the incidence and severity of powdery mildew as compared to control. At 28 days after inoculation, chitosan and thyme essential oil applications performed similarly to their positive controls (BTH and penconazole, respectively), showing a significant reduction in disease incidence (by −84 and −92%) as compared to control. Post-inoculum application of essential oils (Experiment 3) showed an efficacy similar to that of penconazole against powdery mildew. These results indicated that the tested substances could be used as alternatives to fungicides for the control of grey mold and powdery mildew in strawberry, therefore representing a valuable tool for the control of these fungal diseases under the framework of sustainable agriculture. Full article

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. Full article

Alternaria leaf spot seriously threatens the sustainable development of the global apple industry, causing significant losses and reducing fruit quality and yield. The causal agent Alternaria alternata f. sp. mali (Alternaria mali, ALT) produces various molecules to modulate infection, such as cell wall-degrading enzymes, toxins, and elicitor-like molecules. ALT produces the host-specific AM-toxin, an important pathogenicity factor. ALT also releases effectors into apple cells that modify host defense, but these proteins have not yet been described. Here, we identified the pathogenic fungal types responsible for early defoliation from diseased leaves of Fuji (Malus domestica cv. ‘Fuji’) apple collected from five districts in Shandong Province, China. The ALT isolates ALT2 to ALT7 were pathogenic to four apple cultivars, with ALT7 being the most aggressive. We extracted mycotoxins (AM-toxin-2 to AM-toxin-7) from each isolate and used them to treat different apple varieties, which led to leaf-spot symptoms and damaged chloroplasts and nuclear membranes, followed by cell death. AM-toxin-7 produced the most severe symptoms, but chloroplasts remained intact when the mycotoxin was inactivated. Mass spectrometry identified 134 secretory proteins in ALT7 exosomes, and three secreted proteins (AltABC, AltAO, and AltPDE) were confirmed to be involved in apple pathogenesis. Therefore, ALT secretes AM-toxin and secretory proteins as an infection strategy to promote fungal invasion and overcome the host defense system. Full article

The peach (Prunus persica L.) is one of the most important stone-fruit crops worldwide. Nevertheless, successful peach fruit production is seriously reduced by losses due to Monilinia fructicola the causal agent of brown rot. Chitosan has a broad spectrum of antimicrobial properties and may also act as an elicitor that activate defense responses in plants. As little is known about the elicitation potential of chitosan in peach fruits and its impact at their transcriptional-level profiles, the aim of this study was to uncover using RNA-seq the induced responses regulated by the action of chitosan in fruit–chitosan–M. fructicola interaction. Samples were obtained from fruits treated with chitosan or inoculated with M. fructicola, as well from fruits pre-treated with chitosan and thereafter inoculated with the fungus. Chitosan was found to delay the postharvest decay of fruits, and expression profiles showed that its defense-priming effects were mainly evident after the pathogen challenge, driven particularly by modulations of differentially expressed genes (DEGs) related to cell-wall modifications, pathogen perception, and signal transduction, preventing the spread of fungus. In contrast, as the compatible interaction of fruits with M. fructicola was challenged, a shift towards defense responses was triggered with a delay, which was insufficient to limit fungal expansion, whereas DEGs involved in particular processes have facilitated early pathogen colonization. Physiological indicators of peach fruits were also measured. Additionally, expression profiles of particular M. fructicola genes highlight the direct antimicrobial activity of chitosan against the fungus. Overall, the results clarify the possible mechanisms of chitosan-mediated tolerance to M. fructicola and set new foundations for the potential employment of chitosan in the control of brown rot in peaches. Full article

Fungal pathogens pose a major threat to food production worldwide. Traditionally, chemical fungicides have been the primary means of controlling these pathogens, but many of these fungicides have recently come under increased scrutiny due to their negative effects on the health of humans, animals, and the environment. Furthermore, the use of chemical fungicides can result in the development of resistance in populations of phytopathogenic fungi. Therefore, new environmentally friendly alternatives that provide adequate levels of disease control are needed to replace chemical fungicides—if not completely, then at least partially. A number of alternatives to conventional chemical fungicides have been developed, including plant defence elicitors (PDEs); biological control agents (fungi, bacteria, and mycoviruses), either alone or as consortia; biochemical fungicides; natural products; RNA interference (RNAi) methods; and resistance breeding. This article reviews the conventional and alternative methods available to manage fungal pathogens, discusses their strengths and weaknesses, and identifies potential areas for future research. Full article

Polysaccharides and protein–polysaccharide complexes produced from the fungal strain Trametes versicolor have demonstrated bioactive properties that depend on the substrate, the fermentation conditions and also the fungal strain. Likewise, the submerged and controlled fermentation of medicinal mushrooms elicits numerous advantages over traditional processes to produce mycelia and added-value products, along with the exploitation of biodiversity. This study evaluated the growth profile of an indigenous T. versicolor isolate using commercial nutrients that were subsequently replaced with renewable resources, specifically, grape pomace extract (GPE), under static and shaking conditions. The effect of elicitor addition was also assessed using GPE. The process productivity was significantly improved, yielding 21 g/L of biomass. Agitation proved beneficial for all examined cases regarding biomass productivity and substrate consumption rates. The chemical and antioxidant profile of crude intracellular and extracellular polysaccharides was determined, whereby intracellular extracts indicated >50% antioxidant activity. FTIR analysis validated the preliminary chemical characterization of the extracts, whereas the amino acid profile of IPS extracts was also included. Evidently, our study elaborates on the development of a bioconversion concept to valorize wine-making side-streams to formulate added-value products with potential bioactive attributes. Full article

In this work, we present the results of the inoculation of canola seeds (Brassica napus L.) with Trichoderma viride strains that promote the growth of plants. Seven morphologically different strains of T. viride (TvI-VII) were shown to be capable of synthesizing auxins and exhibited cellulolytic and pectinolytic activities. To gain a deeper insight into the molecular mechanisms underlying canola–T. viride interactions, we analyzed the canola stress genes metallothioneins (BnMT1-3) and stringent response genes (BnRSH1-3 and BnCRSH). We demonstrated the presence of cis-regulatory elements responsive to fungal elicitors in the promoter regions of B. napus MT and RSH genes and observed changes in the levels of the transcripts of the above-mentioned genes in response to root colonization by the tested fungal strains. Of the seven tested strains, under laboratory conditions, T. viride VII stimulated the formation of roots and the growth of canola seedlings to the greatest extent. An experiment conducted under field conditions during drought showed that the inoculation of canola seeds with a suspension of T. viride VII spores increased yield by 16.7%. There was also a positive effect of the fungus on the height and branching of the plants, the number of siliques, and the mass of a thousand seeds. We suggest that the T. viride strain TvVII can be used in modern sustainable agriculture as a bioinoculant and seed coating to protect B. napus from drought. Full article

There is a growing demand for molecules of natural origin for biocontrol and biostimulation, given the current trend away from synthetic chemical products. Leachates extracted from plantain stems were obtained after biodegradation of the plant material. To characterize the leachate, quantitative determinations of nitrogen, carbon, phosphorus, and cations (K⁺, Ca²⁺, Mg²⁺, Na⁺), Q2/4, Q2/6, and Q4/6 absorbance ratios, and metabolomic analysis were carried out. The potential role of plantain leachates as fungicide, elicitor of plant defense, and/or plant biostimulant was evaluated by agar well diffusion method, phenotypic, molecular, and imaging approaches. The plant extracts induced a slight inhibition of fungal growth of an aggressive strain of Colletotrichum gloeosporioides, which causes anthracnose. Organic compounds such as cinnamic, ellagic, quinic, and fulvic acids and indole alkaloid such as ellipticine, along with some minerals such as potassium, calcium, and phosphorus, may be responsible for the inhibition of fungal growth. In addition, jasmonic, benzoic, and salicylic acids, which are known to play a role in plant defense and as biostimulants in tomato, were detected in leachate extract. Indeed, foliar application of banana leachate induced overexpression of LOXD, PPOD, and Worky70-80 genes, which are involved in phenylpropanoid metabolism, jasmonic acid biosynthesis, and salicylic acid metabolism, respectively. Leachate also activated root growth in tomato seedlings. However, the main impact of the leachate was observed on mature plants, where it caused a reduction in leaf area and fresh weight, the remodeling of stem cell wall glycopolymers, and an increase in the expression of proline dehydrogenase. Full article