Search Results (449)

Grapevine downy mildew is a major disease in vineyards all around the world, caused by the oomycete Plasmopara viticola (Berk. & M. A. Curtis) Berl. & De Toni. Normally, its control depends almost exclusively on chemical and copper-based fungicides, especially in high-incidence areas with high relative humidity and mild temperatures. However, the European Union is determined to reduce the application of these phytochemicals by at least 50% by 2030, forcing winegrowers to seek alternative low-input strategies for proper sanitary maintenance. Basic substances (BSs), described in European Regulation (EC) 1107/2009, stand out as promising alternatives, but their molecular mechanism of action remains mostly unknown. In this context, this study analyzed the genetic effect in grapevine plants of several commercial products composed of BSs (chitosan, soy lecithin, Equisetum arvense and Salix cortex). All products exhibited promising results, triggering the induction of similar defence mechanisms, which included pathogenesis-related proteins (PRs), involved in direct pathogen repression; stilbenes, capable of producing antimicrobial compounds such as resveratrol and pterostilbene; several hormones, including oxylipins, ethylene, salicylic acid and terpenes, mediating immune signalling; and genes related to structural features of the plant, such as lignin, callose, cellulose and cuticular wax, constituting a first physiological barrier against P. viticola. Disease severity reduction differed among treatments, with Salix cortex showing the highest efficacy (58%), followed by BABA (38%) and LESOY (35%), while LECI and CHIT had minor effects (<9%). Gene expression analyses revealed that Salix cortex modulated the highest percentage of genes (41%), followed by natural infection without treatment (32%), LESOY (27%), BABA (26%), LECI (23%) and CHIT (23%). In terms of defence mechanisms, Salix cortex promoted the most pathways, LESOY induced eight, BABA and LECI seven and CHIT five. Overall, these results indicate that BSs can modulate several defence pathways in grapevine, supporting their potential use as sustainable alternatives for controlling downy mildew. Full article

Cucumber downy mildew, caused by the obligate parasitic oomycete Pseudoperonospora cubensis [(Berkeley & M. A. Curtis) Rostovzev], is a major threat to global cucumber production. Effective disease management relies on rapid and accurate pathogen detection. However, due to the specialized parasitic nature of P. cubensis, conventional methods are often laborious, low-throughput and inadequate, necessitating the development of a new approach for high-throughput sporangia counting. To address this limitation, we developed a rapid, high-throughput flow cytometry (FCM) assay for the direct quantification of P. cubensis sporangia. The optimal staining protocol involved adding 30 µL of 1000× diluted SYBR Green I to 500 µL of sporangial suspension and incubating at room temperature for 20 min. The flow cytometry parameters were set to a high sample loading speed with a 30-s acquisition time. Instrumental settings included an FL1 (green fluorescence) threshold of 8 × 10⁴ and an SSC (side scatter) threshold of 3 × 10⁵, with low gain. Validation against hemocytometer counts revealed a strong positive correlation (r = 0.8352). The assay demonstrated high reproducibility, with relative standard deviations (RSDs) ranging from 1.96–9.84%, and a detection limit of 1–10 sporangia/µL. Operator-dependent variability ranged from 8.85% to 18.79%. These results confirm that the established flow cytometry assay is a reliable and efficient tool for P. cubensis quantification, offering considerable potential for improving cucumber downy mildew monitoring and control strategies. Full article

The RNA interference machinery is crucial for regulating the activity of both native and foreign genes across all eukaryotes. The core protein families involved in this process are Dicer-like, Argonaute, and RNA-dependent RNA polymerase. However, plants exhibit remarkable diversity within each family and extensively use RNA interference mechanisms in their intricate immune responses. This review examines the role of RNA interference in plant interactions with various pathogens, including viruses, viroids, fungi, oomycetes, and bacteria. Plant diseases cause an estimated $220 billion in annual damage, with microorganisms accounting for approximately $150 billion. Hence, the focus is on the most severe plant diseases, specifically those caused by fungi and viruses. Additionally, recent biotechnological advancements are discussed, with an emphasis on the application of RNA interference for the development of novel plant defence strategies. Full article

The genus Streptomyces is the largest group within the phylum Actinobacteria, recognized for producing antibiotics and enzymes, with wide applications in medicine and biological control for crop protection against phytopathogens. In this study, the Streptomyces sp. Caat 5-35 strain, isolated from soil of the Caatinga biome in Brazil, and identified by analysis of the 16S rRNA gene, demonstrated its antagonistic effect in vitro in dual cultures against Phytophthora palmivora, Colletotrichum acutatum, Fusarium oxysporum, Rhizoctonia solani, Sclerotinia sclerotiorum, and Fusarium graminearum. Caat 5-35 inhibited mycelial growth ranging from 19% to 73.3%. Compounds purified by prep-HPLC from extracts were identified by spectral data analysis using UHPLC-triple-TOF-MS/MS, or nuclear magnetic resonance (NMR). This work demonstrated for the first time the anti-oomycete activity of albofungin, its derivatives, and albonoursin against P. palmivora. Moreover, the growth inhibition of Colletotrichum gloeosporioides by albonoursin and the antibacterial effect of 2-chloroadenosine and 5′-O-sulfamoyl-2-chloroadenosine against Pectobacterium carotovorum were demonstrated as novel findings. Caat 5-35 exhibited the ability to solubilize phosphates and produce cellulases on CMC agar. The findings of this study, in combination with in vitro bioassays on cacao pods (Theobroma cacao L.) inoculated with the antagonist strain and P. palmivora APB-35, demonstrate that Streptomyces sp. Caat 5-35 is a source of natural products with applications in agriculture and could serve as an alternative for crop protection. Full article

Liquid chromatography–mass spectrometry analysis of Pseudomonas chlororaphis subsp. phenazini S1Bt23 extracts detected phenazine-1-carboxylic acid (PCA) and 2-hydroxyphenazine (2-OH-PHZ) as the main phenazine derivatives. We investigated their relative contributions to the antagonistic activity of strain S1Bt23 against Pythium arrhenomanes, a root rot pathogen of corn. CRISPR-Cas9 knockouts were carried out on the phzF gene, required for PCA synthesis, and the phzO gene, which is involved in converting PCA to 2-OH-PHZ. Deletion of the phzF gene abrogated the production of PCA and 2-OH-PHZ, and the ΔphzF mutant lost the antagonism against Pythium arrhenomanes. In contrast, deletion of the phzO gene created a 2-OH-PHZ-negative mutant with intact antagonistic ability. Concordantly, S1Bt23 wild type and the ΔphzO mutant, but not the ΔphzF mutant, significantly bioprotected corn seeds of a susceptible inbred variety, CO441, from P. arrhenomanes. At equimolar amounts of 75 nM, synthetic PCA inhibited Pythium growth, whereas 2-OH-PHZ did not. This highlights the critical contribution of PCA to the biocontrol activity of strain S1Bt23 against P. arrhenomanes. Unexpectedly, deletion of phzO did not result in additional PCA accumulation. This suggests that the conversion of PCA to 2-OH-PHZ by S1Bt23 is a potential protective mechanism against the overproduction of lethal cellular doses. This study paves the way for bioengineering strain S1Bt23 into a more effective biopesticide. Full article

Plant peptides represent a novel molecular tool in crop science due to their essential regulatory roles in plant growth, development, and responses to biotic and abiotic stresses. Although numerous bioactive plant peptides have been identified, a major gap remains in translating these discoveries into practical strategies for crop protection. Synthetic peptides are increasingly recognized as promising biological agents for enhancing crop productivity and protection in an environmentally sustainable manner. In this study, we demonstrate that the potato elicitor peptide StPep1, applied as a foliar spray at nanomolar concentrations (10–100 nM), strongly enhances resistance to the oomycete pathogen Phytophthora infestans in Solanum tuberosum cv. Gala under controlled climate chamber conditions. Preventive treatment 24 h prior to inoculation markedly reduced disease symptoms, with treated plants exhibiting a phenotype comparable to uninoculated controls. These findings highlight the potential of low-dose StPep1 as an environmentally friendly and cost-effective bioprotective agent, providing a foundation for future translational research and small-scale agricultural applications. Full article

The European catfish (Silurus glanis, Linnaeus 1758), commonly known as the wels catfish, is one of the largest freshwater fish in Europe and an ecologically and economically important species in both natural ecosystems and aquaculture. Its broad native distribution, together with the rapid growth of farming practices, increases concerns about pathogen dissemination and their potential impact on biodiversity, animal health, and potential risks to human healthcare. This review is based on a structured literature search following PRISMA recommendations for narrative reviews and summarizes current knowledge on the main pathogen groups affecting S. glanis—viruses (ranaviruses, alloherpesviruses), bacteria (Aeromonas spp., Edwardsiella spp.), protozoan and metazoan parasites (Ichthyophthirius multifiliis, Thaparocleidus spp., Eustrongylides spp., Contracaecum larvae), and oomycetes (Saprolegnia spp., Branchiomyces spp.). Within the One Health approach, particular attention is given to zoonotic pathogens such as Aeromonas spp., Edwardsiella tarda, and helminths like Eustrongylides and Contracaecum, which may cause risks to human health through contaminated water or consumption of raw or undercooked fish. The review integrates findings from field surveys, regional case studies such as those from the Danube basin, and data from the authors’ doctoral research. Because the wels catfish is increasingly cultivated and serves as an apex predator in natural habitats, its effective disease management is critical for both aquaculture and wild populations, and also for the food chains at all. Strengthened surveillance, health monitoring, and biosecurity measures are essential preventing the introduction and spread of pathogens into new hosts and habitats. Through the underlining of major catfish pathogen groups, this review highlights key challenges within the One Health approach and underscores the need for integrated health monitoring, biosecurity, and environmental management strategies. Full article

Phytophthora root rot (PRR), which is caused by the oomycete pathogen Phytophthora sojae (P. sojae), is one of the most devastating diseases affecting global soybean production. The deployment of resistance (Rps) genes through molecular breeding is a sustainable strategy to control this disease. In this study, we finely mapped a novel resistance gene using two recombinant inbred line (RIL) populations: one comprising 248 F_8:11 lines from a cross between the resistant cultivar ‘Guizao 1’ and the susceptible ‘B13’, and another consisting of 196 F_7:8 lines from a cross between ‘Wayao’ (resistant) and ‘Huachun 2’ (susceptible). The gene in ‘Guizao 1’, designated as Rps15, was delimited to a 78 kb genomic interval on chromosome 3 (bin31), spanning the physical positions from 4,292,416 to 4,370,772 bp. This region contains eight predicted genes. Similarly, the resistance locus in ‘Wayao’ was mapped to a broader region on chromosome 3 (approximately 324 kb; 3,968,039–4,292,863 bp), which encompasses 16 genes. Expression analysis via quantitative real-time PCR of the candidate genes suggested that Glyma.03g036000 is likely involved in the resistance response to PRR. The fine mapping of this novel Rps locus provides a foundation for the future cloning of Rps15 and can be expected to accelerate the development of P. sojae-resistant soybean cultivars through marker-assisted selection. Full article

Plant–pathogen interactions are complex biological processes characterized by dynamic changes in genes expression. In molecular plant pathology research, RT-qPCR has proven to be a valuable tool for investigating plant–pathogen interactions by examining gene expression changes in both plants and pathogens during infection. The choice of reliable reference genes is crucial, as this directly affects the robustness of normalization and the accuracy of analyzing the expression of genes of interest. A systematic literature search was conducted across relevant academic databases, resulting in the selection of 47 articles (38 on fungi and oomycetes, 7 on bacteria and 2 covering both bacteria, fungi and oomycetes) that evaluated the stability of 190 candidate reference genes. The most used reference genes in plant—fungal and oomycete pathosystems were GAPDH, ACT, TUB and EF, whereas UBQ, TUB, EF and ACT were most used in plant—bacterial pathosystems. Reference genes revealed considerable variability in their stability across different crops, pathogens and experimental conditions. Notably, several classical reference genes, traditionally assumed to maintain stable expression, exhibited considerable variability, supporting concerns regarding their reliability as universal references. Therefore, this review provides important insights for researchers seeking to identify suitable reference genes for their validation studies in plant–pathogen interaction. Full article

Studies that correlate the structure of a molecule with its biological function or activity are useful in identifying the structural components that determine how the molecule interacts with binding proteins. This enables the synthesis of structural analogs with desirable properties, such as agrochemicals that improve plant developmental traits or adaptations to environmental stress. This review highlights a group of plant defense-inducing small signaling molecules characterized by a fatty acid-derived molecular skeleton with different functional groups. These include medium chain 3-hydroxy fatty acids (mc-3-OH-FAs) derived from the bacterial cell wall; green leaf volatiles (GLVs), which comprise primary aldehydes, alcohols, and esters derived from plant membranes; insect-derived fatty acid-amino acid conjugates (FACs), caeliferins, and bruchins; and sphingoid bases from oomycete pathogens. These molecules are typically lipophilic, and their mechanism of action is likely determined by both specific structural hallmarks and physicochemical properties. They activate defense responses via signaling pathways and are therefore presumed to interact with extra- or intracellular receptor proteins. However, classical receptors have only been characterized for mc-OH-FAs, sphingoid bases, and FACs. Structure–function studies may reveal structural features of these molecules that are critical for binding to receptors and relevant to the specificity of these interactions. This is particularly significant for GLVs, which have been extensively investigated for their roles in plant stress signaling and interplant communication, yet no specific receptor has been identified to date. This comparative review aims to shed light on perception of GLVs and other small molecules. Full article

Urban green spaces are essential components of city ecosystems, providing environmental and social benefits while simultaneously serving as potential entry points for invasive plant pathogens. In recent years, increasing attention has been directed toward the role of urban environments as reservoirs and transmission corridors for oomycetes, a group of highly destructive microorganisms affecting trees and shrubs. This study aimed to investigate the diversity and potential introduction pathways of oomycetes in three Warsaw parks representing distinct ecological settings: a historical city park, a large landscape park with aquatic features, and a newly constructed linear park. Samples of soil, and surface water were collected and analysed using standard isolation and molecular identification methods. Four species were identified: Phytophthora cactorum, P. cambivora, Phytopythium vexans, and Ph. montanum—the latter two representing first records for urban parks in Poland. The results indicate that nursery plant material, surface water systems, and wildlife activity, particularly birds, are likely contributors to the introduction and spread of these pathogens in city landscapes. The findings underscore the growing phytosanitary risk associated with urban greenery, where the interplay of anthropogenic disturbance, high plant turnover, and complex hydrological networks facilitates pathogen establishment. This research highlights the urgent need to integrate urban biosecurity strategies with routine molecular monitoring, nursery inspections, and wildlife surveillance to limit further dissemination of invasive oomycetes and enhance the resilience of urban tree populations. Full article

Chitin is an essential polysaccharide of the fungal cell wall, critical for structural integrity, cell division and, in pathogenic fungi, virulence. As chitin is absent in both plant and mammalian systems, chitin synthases are considered attractive targets for the specific control of fungal pathogens. Yet despite decades of research, structural information on chitin synthases was lacking and inhibitors have failed to gain approval in the clinic. Current inhibitors are also ineffective against major agricultural pathogens such as Aspergillus and Fusarium species, largely due to the presence of multiple chitin synthase isoforms in filamentous fungi and the cell wall compensatory response induced under stress. However, recent cryo-electron microscopy structures of Class I chitin synthases from yeasts Saccharomyces cerevisiae and Candida albicans and an oomycete chitin synthase have provided unprecedented insights into the structural and mechanistic properties of these large, transmembrane proteins. These studies revealed conserved, domain-swapped homodimer architectures, distinct substrate binding and catalytic pockets, and sophisticated intrinsic regulatory mechanisms. With these breakthroughs, this review summarises our current understanding of fungal chitin biosynthesis, the challenges that remain to fully biochemically characterise these enzymes, and considers how the new structural insights may guide the development of broad-spectrum antifungals. Full article

Lysobacter enzymogenes is well known for producing extracellular enzymes and bioactive molecules that suppress a wide range of plant pathogens, including fungi such as Rhizoctonia and Fusarium spp. and oomycetes such as Phytophthora infestans. It also exhibits antagonistic effects against Gram-negative bacteria through the type IV secretion system. Interestingly, L. enzymogenes JCK1421, isolated from the rhizosphere of pine forests, showed neither antifungal nor antibacterial activity, in contrast to other L. enzymogenes strains. However, foliar application of JCK1421 significantly reduced disease symptoms in tomato seedlings challenged with Ralstonia solanacearum. To elucidate the underlying defense mechanisms, comparative transcriptome analysis integrated with network and pathway enrichment approaches was performed. Comparative transcriptome and network analyses identified signaling modules activated by JCK1421 in pathogen-free plants and further enhanced upon R. solanacearum challenge. In challenged plants, JCK1421 treatment strongly induced resistance-related genes, including those encoding Ca²⁺-dependent proteins and ion channels, hormone biosynthesis components, and mitogen-activated protein kinase cascades—hallmarks of plant immune responses. These findings demonstrate that JCK1421 provides an effective model for investigating microbe-associated defense activation in plants, highlighting its potential as an eco-friendly agent for sustainable crop protection. Full article

Soil-borne plant pathogens pose a serious threat to global food security by causing extensive yield losses and compromising crop quality. Conventional chemical-based control methods often prove inadequate, environmentally harmful, and disruptive to beneficial soil microbiota, highlighting the urgent need for sustainable alternatives. Plant growth-promoting fungi (PGPF) have emerged as effective biocontrol agents capable of suppressing diverse soil-borne pathogens while simultaneously enhancing plant growth and resilience. This review synthesizes current knowledge on the tripartite interactions among plants, pathogens, and PGPF within the rhizosphere, with emphasis on their roles in disease suppression, rhizosphere competence, and plant health promotion. The findings highlight that PGPF such as Trichoderma, Penicillium, Aspergillus, non-pathogenic Fusarium, hypovirulent binucleate Rhizoctonia and sterile fungi can significantly reduce diseases caused by fungi, oomycetes, bacteria, nematodes, and protists through mechanisms including antibiosis, hyperparasitism, competition, and induction of systemic resistance. Evidence also indicates that consortium approaches and bioformulations enhance field efficacy compared to single-strain applications. Despite this progress, challenges such as variability in field performance, limited shelf life of inoculants, and gaps in understanding ecological interactions constrain large-scale use. Overall, the review underscores that PGPF-based strategies represent a promising and sustainable alternative to chemical pesticides, with strong potential for integration into holistic crop disease management under changing climatic conditions. Full article