Search Results (323)

The growing demand for food and the environmental impact of conventional agriculture have prompted the search for sustainable alternatives. Phycocyanin (PC) and total phenolic compounds (TPC) extracted from Spirulina platensis have shown potential for the biological control of phytopathogens. The extraction method directly influences the yield and stability of these compounds. This study aimed to establish an efficient extraction protocol for PC and TPC and to evaluate their antimicrobial efficacy in vitro against Colletotrichum orchidearum, Fusarium nirenbergiae, and Alternaria sp. isolated from hydroponically grown lettuce. The phytopathogens were identified based on phylogenetic analyses using sequences from the ITS, EF1-α, GAPDH, and RPB2 gene regions. This is the first report of C. orchidearum in hydroponic lettuce culture in Brazil, expanding its known host range. Extracts were obtained using hydroalcoholic solvents and phosphate buffer (PB), combined with ultrasound-assisted extraction (bath and probe). The extracts were tested for in vitro antifungal activity. Data were analyzed by ANOVA (p < 0.05), followed by Tukey’s test. The combination of the PB and ultrasound probe resulted in the highest PC (95.6 mg·g⁻¹ biomass) and TPC (21.9 mg GAE·g⁻¹) yields, using 10% (w/v) biomass. After UV sterilization, the extract retained its PC and TPC content. The extract inhibited C. orchidearum by up to 53.52% after three days and F. nirenbergiae by 54.17% on the first day. However, it promoted the growth of Alternaria sp. These findings indicate that S. platensis extracts are a promising alternative for the biological control of C. orchidearum and F. nirenbergiae in hydroponic systems. Full article

The Alternaria alternata tangerine pathotype causes Alternaria brown spot, a devastating disease of susceptible tangerine varieties and their hybrids. Alternaria citri toxin (ACT) is the primary virulence factor, but the regulatory mechanisms governing ACT synthesis remain unclear. Deubiquitinating enzymes maintain ubiquitination homeostasis and regulate fungal pathogenicity, yet their role in A. alternata remains unexplored. We characterized 13 ubiquitin-specific protease (UBP) family members in A. alternata tangerine pathotype. Six UBP genes (Aaubp2, Aaubp3, Aaubp4, Aaubp6, Aaubp14, and Aaubp15) regulated mycelial growth. Aaubp14 deletion abolished sporulation, while mutations of Aaubp3, Aaubp4, Aaubp6, Aaubp8, and Aaubp15 altered conidial morphology. qRT-PCR demonstrated distinct host-induced expression patterns among Aaubp genes. Pathogenicity tests showed that ΔAaubp6, ΔAaubp14, and ΔAaubp15 mutants failed to produce lesions on Citrus reticulata cv. Hongjv leaves. Moreover, Aaubp14 deletion significantly suppressed ACT biosynthesis gene expression and blocked ACT production. Comparative proteomics showed Aaubp14 regulates ACT biosynthesis by modulating protein ubiquitination in metabolic pathways and controls pathogenicity via a complex network. Our findings elucidate Aaubp gene function in development and pathogenicity, particularly the Aaubp14-mediated regulation mechanism, providing insights into ubiquitination-mediated pathogenicity in phytopathogenic fungi. 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 volatile organic compounds (VOCs) produced by K. cowanii Ch1 play a significant role in the inhibition of the mycelial growth of phytopathogen strains. As a continuation of our previous studies, we aim to elucidate the mechanisms of the responses of K. cowanii Ch1 against S. rolfsii during a colonization competence interaction in the presence and absence of a mixture of bacterial VOCs under in vitro conditions. The results of this study showed that, in the absence of bacterial VOCs, K. cowanii Ch1 cannot compete against S. rolfsii, and the RNA-Seq analysis revealed the differential expression of genes related to the oxidative stress response in K. cowanii Ch1 for survival. However, in the presence of bacterial VOCs, an interesting phenotypical response was observed in K. cowanii Ch1, resulting in the mycelial growth inhibition of S. rolfsii. The upregulated genes were related to the siderophore-mediated iron transport system, zinc ion transport system, antibiotic biosynthesis monooxygenase, carbohydrate metabolism, polyketide synthase modules, and related proteins, and katG was probably related to the phenotype resulting in the formation of gas bubbles by K. cowanii. In addition, the VOC profile analyzed at 36 h for bacterial growth revealed a cocktail with an ability to increase the competence of K. cowanii Ch1 against S. rolfsii in vitro and in vivo. This study provides evidence regarding the key role that VOCs play during the colonization competition involving K. cowanii Ch1, the comprehension of which may enable the development of new biocontrol strategies. Full article

Magnaporthe oryzae (M. oryzae) is a phytopathogenic fungus that inflicts damage on vital crops, particularly rice. Its asexual reproduction leads to the generation of numerous conidia, which is a critical factor contributing to the prevalence of rice blast disease. However, the molecules regulating the asexual reproduction of M. oryzae are unknown. In our study, to identify the molecules capable of regulating the asexual reproduction of M. oryzae, compositions of the complete medium (CM) were screened. Results showed that acid-hydrolyzed casein (AHC) could remarkably promote conidial production. One M. oryzae conidiation inducer was isolated from AHC using high-performance liquid chromatography (HPLC) under the guidance of bioassay. Its structure was further elucidated as a decapeptide compound (pyroGlu-EQNQEQPIR) by LC-MS/MS, chemical synthesis, and conidium-inducing assays, named M. oryzae conidiation inducer decapeptide (MCIDP). MCIDP could significantly promote the conidiation of M. oryzae and two other filamentous ascomycetes (Botrytis cinerea and Fusarium graminearum). The Mps1 MAPK cascade signaling pathway is crucial for conidiation, and the effect of MCIDP on this pathway was investigated to elucidate the mechanism underlying conidiation enhancement. qRT-PCR analysis demonstrated that MCIDP could remarkably upregulate the gene expression within the Mps1 MAPK cascade signaling pathway, especially the WSC2, WSC3, PKC1, MKK1, MPS1, and MIG1. Furthermore, the ΔMowsc1, ΔMowsc2, ΔMowsc3, and ΔMomid2 mutant strains were constructed. Bioassay results showed that MCIDP failed to promote conidial formation and hyphal growth in these mutant strains. These findings indicate that MCIDP promotes conidiation of M. oryzae by modulating the Mps1 MAPK signaling pathway. Full article

Fusarium verticillioides is a globally prevalent phytopathogenic fungus responsible for multiple diseases in maize and a major producer of the mycotoxin fumonisin B1 (FB1), a highly toxic fungal secondary metabolite (FSM). The histone code, which includes reversible modifications such as acetylation and methylation, plays a critical role in regulating chromatin structure and gene expression. In fungi, di- and tri-methylation of histone H3 at lysine 9 (H3K9me2/3) serves as a key epigenetic mark associated with heterochromatin formation and transcriptional repression. In this study, we identified and characterized a putative heterochromatin protein 1 (HP1) family member in F. verticillioides, designated FvHP1, based on conserved domain architecture and phylogenetic analyses. FvHP1 retains essential residues required for H3K9me2/3 recognition, supporting its functional conservation within the HP1 protein family. Phenotypic analysis of the ΔFvHP1 mutant revealed impaired vegetative growth, reduced conidiation and virulence, and altered FB1 mycotoxin production. Additionally, the accumulation of red pigment in the mutant was linked to the deregulation of secondary metabolism, specifically the overproduction of fusarubin-type naphthoquinones, such as 8-O-methylnectriafurone. These results support the role of FvHP1 in facultative heterochromatin-mediated repression of sub-telomeric biosynthetic gene clusters, including the pigment-associated PGL1 cluster. Our findings provide new insights into the epigenetic regulation of fungal pathogenicity and metabolite production, as well as the first evidence of a functional HP1 homolog in F. verticillioides. Full article

The nonsense-mediated mRNA decay (NMD) is extensively involved in physiological, pathological, and stress response processes in humans and plants. However, the NMD in phytopathogenic fungi has not yet been thoroughly investigated. In this study, we identified and performed domain analysis on the core components of the NMD in ten globally widespread phytopathogenic fungi that cause significant economic losses. The core components of NMD in these fungi exhibit high similarity to their homologous genes in humans, while also possessing certain specificities. The core factors of the NMD, including the Up-frameshift factors (UPFs) and the exon junction complex (EJC), are generally conserved among phytopathogenic fungi. Notably, suppressors with morphological effects on genitalia (SMG) genes are absent in these fungi, which bears some similarity to the EJC-independent NMD degradation mechanism observed in Saccharomyces cerevisiae. Interestingly, plant pathogenic fungi contain highly homologous genes of the EJC complex, suggesting the presence of an EJC-dependent NMD degradation mechanism. In summary, our findings demonstrate that NMD are prevalent in plant pathogenic fungi, providing a research foundation for subsequent studies on NMD in their growth, development, and involvement in pathogenic processes. Full article

Fungal phytopathogens employ effector proteins and secondary metabolites to subvert host immunity. Effector proteins have attracted widespread interest in infection, especially for unknown, unreported genes. However, the type of protein remains much less explored. Here, we combined transcriptome analysis and functional validation to identify virulence-associated genes in Fusarium graminearum during fungi infection. A unique secreted protein, FGSE02, was significantly upregulated in the early infection stage. Proteomic characterization revealed that the protein contains a functional signal peptide but lacks known domains. The transient expression of FGSE02 in Nicotiana benthamiana induced rapid cell death, while gene knockout stains reduced fungal virulence without affecting growth. Our findings highlight FGSE02 as a key virulence factor, offering potential targets for disease control. Taken together, the results of this study identify a pathogenic factor and provide new insights into the development of green pesticides. Full article

Soft rot caused by Dickeya fangzhongdai is a destructive disease in Phalaenopsis production that seriously impacts the quality and yield of Phalaenopsis. To explore the molecular mechanisms underlying disease resistance, transcriptome analysis was conducted on resistant and susceptible Phalaenopsis varieties. By comparing the transcriptomes of the resistant variety ‘ES L20’ and the susceptible variety ‘Zishuijing’ after D. fangzhongdai infection, Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses were performed. The results revealed that the differentially expressed genes were mainly enriched in pathways related to plant–pathogen interaction, plant hormone signal transduction, and the phenylpropanoid biosynthetic pathway. In the resistant variety ‘ES L20’, some genes in the Ca²⁺ pathway, PAMP-triggered immunity pathway, and Effector-triggered immunity pathway were significantly up-regulated. Analysis of the transcriptome levels of genes in the phytohormone-related pathways showed that genes associated with IAA (indole-3-acetic acid), salicylic acid, and jasmonic acid signal transduction pathways were all up-regulated in the resistant variety after inoculation. Furthermore, the analysis of genes in the phenylpropanoid biosynthesis pathway demonstrated significant up-regulation in the resistant variety. The determination of lignin content validated this result, confirming the crucial role of lignin synthesis in Phalaenopsis defense against soft rot. These findings suggest that the differentially expressed genes in phytopathogenic interaction pathways, along with those involved in hormone-related and lignin synthesis pathways, play important roles in Phalaenopsis resistance to soft rot. This study provides valuable insights into the molecular basis of Phalaenopsis resistance to soft rot and may contribute to the development of effective disease control strategies. Full article

Tomato is a widely cultivated vegetable crop worldwide. It is susceptible to various phytopathogens, including fungi, bacteria, viruses, and nematodes. In 2024, an unknown leaf spot disease outbreak, characterized by distinct brown necrotic lesions on leaves, was observed in tomato plants in Yunnan Province, China. Through rigorous pathogen isolation and the fulfillment of Koch’s postulates, it was proved that the fungal isolate could infect tomato leaves and cause typical symptoms. The pathogen isolated from tomato leaves was identified as Nigrospora oryzae based on its morphology and using a multilocus sequence analysis method with the internal transcribed spacer gene (ITS1), beta-tubulin gene (TUB2), and translation elongation factor 1-alpha gene (TEF1-α). This represents the first documented case of N. oryzae infecting tomatoes in the world. Given the damage caused by N. oryzae to tomato plants, we explored biocontrol methods. Through a dual-culture assay on PDA plates, Bacillus velezensis B31 demonstrated significant biocontrol potential, exhibiting strong antagonistic activity toward N. oryzae. In addition, we developed a polyethylene glycol (PEG)-mediated transformation system that successfully introduced pYF11-GFP into the protoplasts of N. oryzae. This achievement provides a foundation for future genetic manipulation studies of N. oryzae. Full article

Background/Objectives: The agriculture sector faces significant challenges due to global climate change, environmental stressors, and rapid population growth, compounded by unsustainable farming practices. This study investigates the potential of the endophytic bacterial strain B.B.Sf.2, isolated from the bark of Salvia fruticosa and identified as Bacillus velezensis through phylogenomic analyses. Methods: To address these issues, eco-friendly techniques, such as the application of plant-associated microbes, are gaining attention. Genome mining revealed numerous secondary metabolite biosynthetic gene clusters associated with plant growth promotion, biocontrol, colonization, and defense elicitation. Results: The strain exhibited strong antagonistic activity against phytopathogens, mediated by diffusible and volatile compound production, along with plant-growth-promoting traits and environmental adaptability. Genome mining revealed numerous secondary metabolite biosynthetic gene clusters associated with plant growth promotion, biocontrol, colonization, and defense elicitation. B.B.Sf.2 effectively inhibited Colletotrichum species causing olive anthracnose and suppressed Botrytis cinerea, the gray mold pathogen, in post-harvest studies on infected fruits. Bioautography of ethyl acetate extracts demonstrated bioactivity against B. cinerea, attributed to iturin-like metabolites. The extracts maintained bioactive properties regardless of fungal interaction. Furthermore, the strain significantly promoted the growth of Arabidopsis thaliana via diffusible and volatile compounds. Conclusions: Our results highlight the multifunctional potential of B.B.Sf.2 as a biocontrol and growth-promoting agent, warranting further evaluation in field applications to enhance sustainable agriculture. Full article

The overuse of pesticides has led to resistance in phytopathogens, posing significant threats to global food security and environmental health. Antimicrobial peptides (AMPs), small molecules produced by various organisms as part of their innate immune defense, exhibit broad-spectrum antimicrobial activity with a lower risk of resistance development. These properties make AMPs promising candidates for sustainable agricultural practices. However, challenges such as high production costs, instability, and potential toxicity to plant cells have hindered their widespread application. This review provides a comprehensive overview of the discovery, classification, and antimicrobial mechanisms of AMPs, focusing on their roles in plant protection. It also explores strategies for identifying and optimizing AMPs, including structural modifications, targeted delivery systems, and production methods using plant- and microbe-based expression systems. Additionally, the review highlights the potential of transgenic approaches to enhance crop resistance by expressing AMP genes in plants. Despite the challenges, AMPs offer a transformative opportunity for modern agriculture, providing innovative solutions to combat plant diseases while reducing reliance on conventional pesticides. Continued research and technological advancements are essential to fully realize the potential of AMPs in sustainable plant protection. Full article

The Clonostachys genus is a saprophytic soil microfungus (Ascomycota). It exhibits significant ecological adaptability and plays a crucial role in maintaining the balance of soil microorganisms. Species within this genus are natural antagonists of insects and nematodes, and they also combat phytopathogenic fungi through mycoparasitism. This process involves producing lytic enzymes and competing for space and nutrients. Clonostachys species are effective biocontrol agents in agriculture and have been utilized to manage pests affecting many high-value commercial crops, acting as a natural biopesticide. They inhabit plant tissues, boosting plant defenses and activating genes for water and nutrient uptake, enhancing plant performance. Additionally, they produce enzymes and bioactive metabolites with antimicrobial, antifungal, nematocidal, anticancer, and antioxidant properties. Clonostachys species can degrade plastic waste and remove hydrocarbons from crude oil-contaminated sites when functioning as endophytes, positioning Clonostachys as a promising candidate for reducing environmental pollution. There are still challenges and limitations, such as the continuous surveillance of the safety of Clonostachys species on plants, the establishment of commercial applications, formulation viability, and variability due to field conditions. These issues will have to be addressed. This review provides an overview of Clonostachys ecology, morphology, classification, and biotechnological applications, emphasizing its significance in various fields. Full article

Cross-kingdom infections, where pathogens from one kingdom infect organisms of another, were historically regarded as rare anomalies with minimal concern. However, emerging evidence reveals their increasing prevalence and potential to disrupt the delicate balance between plant, animal, and human health systems. Traditionally recognized as plant-specific, a subset of phytopathogens, including certain fungi, bacteria, viruses, and nematodes, have demonstrated the capacity to infect non-plant hosts, particularly immunocompromised individuals. These pathogens exploit conserved molecular mechanisms, such as immune evasion strategies, stress responses, and effector proteins, to breach host-specific barriers and establish infections. Specifically, fungal pathogens like Fusarium spp. and Colletotrichum spp. employ toxin-mediated cytotoxicity and cell-wall-degrading enzymes, while bacterial pathogens, such as Pseudomonas syringae, utilize type III secretion systems to manipulate host immune responses. Viral and nematode phytopathogens also exhibit molecular mimicry and host-derived RNA silencing suppressors to facilitate infections beyond plant hosts. This review features emerging cases of phytopathogen-driven animal and human infections and dissects the key molecular and ecological determinants that facilitate such cross-kingdom transmission. It also highlights critical drivers, including pathogen plasticity, horizontal gene transfer, and the convergence of environmental and anthropogenic stressors that breach traditional host boundaries. Furthermore, this review focuses on the underlying molecular mechanisms that enable host adaptation and the evolutionary pressures shaping these transitions. To address the complex threats posed by cross-kingdom phytopathogens, a comprehensive One Health approach that bridges plant, animal, and human health strategies is advocated. Integrating molecular surveillance, pathogen genomics, AI-powered predictive modeling, and global biosecurity initiatives is essential to detect, monitor, and mitigate cross-kingdom infections. This interdisciplinary approach not only enhances our preparedness for emerging zoonoses and phytopathogen spillovers but also strengthens ecological resilience and public health security in an era of increasing biological convergence. Full article

Powdery mildew, a debilitating phytopathogen caused by biotrophic fungi within the order Erysiphales, endangers crop yields and global food security. Although traditional approaches have largely emphasized resistant cultivar development and chemical control, novel strategies are necessary to counter the advent of challenges, such as pathogen adaptation and climate change. This review fully discusses three principal areas of pathogen effector functions, e.g., the reactive oxygen species (ROS)-suppressive activity of CSEP087, and host susceptibility factors, like vesicle trafficking regulated by Mildew Locus O (MLO). It also briefly mentions the transcriptional regulation of resistance genes mediated by factors, like WRKY75 and NAC transcription factors, and post-transcriptional regulation via alternative splicing (As). In addition, this discussion discusses the intricate interactions among powdery mildew, host plants, and symbiotic microbiomes thereof, highlighting the mechanism through which powdery mildew infections disrupt the foliar microbiota balance. Lastly, we present a new biocontrol approach that entails synergistic microbial consortia, such as combinations of Bacillus and Trichoderma, to induce plant immunity while minimizing fungicide dependency. Through the study of combining knowledge of molecular pathogenesis with ecological resilience, this research offers useful insights towards climate-smart crop development and sustainable disease-management strategies in the context of microbiome engineering. Full article