Search Results (8,184)

African swine fever (ASF) is a lethal disease of domestic pigs that is currently challenging swine production in large areas of Eurasia. The causative agent, ASF virus (ASFV), is a large, double-stranded and structurally complex virus. The ASFV genome encodes for more than 160 proteins; however, the functions of most of these proteins are still in the process of being characterized. The ASF gene R298L, which has previously been characterized as able to encode a functional serine protein kinase, is expressed late in the virus infection cycle and may be part of the virus particle. There is no description of the importance of the R298L gene in basic virus functions such as replication or virulence in the natural host. Based on its evolution, it is proposed that there are four different phenotypes of R298L of ASFV in nature, which may have potential implications for R298L functionality. We report here that a recombinant virus lacking the R298L gene in the Georgia 2010 isolate, ASFV-G-∆R298L, does not exhibit significant changes in its replication in primary cultures of swine macrophages. In addition, when experimentally inoculated in pigs, ASFV-G-∆R298L induced a fatal form of the disease similar to that caused by the parental virulent ASFV-G. Therefore, deletion of R298L does not significantly affect virus replication and virulence in domestic pigs of the ASFV Georgia 2010 isolate. Full article

For the safe use of microbiome-based solutions in agriculture, the genome sequencing of strains composing the inoculum is mandatory to avoid the spread of virulence and multidrug resistance genes carried by them through horizontal gene transfer to other bacteria in the environment. Moreover, the annotated genomes can enable the design of specific primers to trace the inoculum into the soil and provide insights into the molecular and genetic mechanisms of plant growth promotion and biocontrol activity. In the present work, the genome sequences of some members of beneficial microbial consortia that have previously been tested in greenhouse and field trials as promising biofertilizers for maize, tomato and wheat crops have been determined. Strains belong to well-known plant-growth-promoting bacterial genera such as Bacillus, Burkholderia, Pseudomonas and Rahnella. The genome size of strains ranged from 4.5 to 7.5 Mbp, carrying many genes spanning from 4402 to 6697, and a GC content of 0.04% to 3.3%. The annotation of the genomes revealed the presence of genes that are implicated in functions related to antagonism, pathogenesis and other secondary metabolites possibly involved in plant growth promotion and gene clusters for protection against oxidative damage, confirming the plant-growth-promoting (PGP) activity of selected strains. All the target genomes were found to possess at least 3000 different PGP traits, belonging to the categories of nitrogen acquisition, colonization for plant-derived substrate usage, quorum sensing response for biofilm formation and, to a lesser extent, bacterial fitness and root colonization. No genes putatively involved in pathogenesis were identified. Overall, our study suggests the safe application of selected strains as “plant probiotics” for sustainable agriculture. Full article

Periodontitis disproportionately affects genetic ancestral/ethnic groups. To characterize the oral microbiome from different genetic ancestral/ethnic groups, we collected 161 dental plaque samples from self-identified African Americans (AAs), Caucasian Americans (CAs), and Hispanic Americans (HAs) with clinical gingival health or biofilm-induced gingivitis on an intact periodontium. DNA was extracted from these samples, and then DNA libraries were prepared and sequenced using an Illumina NovaSeq high-throughput sequencer. We found significant differences in the diversity and abundance of microbial taxa among dental plaque samples of the AA, CA, and HA groups. We also identified unique microbial species in a self-reported ancestral/ethnic group. Moreover, we revealed variations in functional potentials of the oral microbiome among the three ancestral/ethnic groups, with greater diversity and abundance of antibiotic-resistant genes in the oral microbiome and significantly more genes involved in the modification of glycoconjugates and oligo- and polysaccharides in AAs than in CAs and HAs. Our observations suggest that the variations in the oral microbiome associated with ancestral/ethnic backgrounds may directly relate to their virulence potential including their abilities to induce host immune responses and to resist antibiotic treatment. These finding can be a steppingstone for developing precision medicine and personalized periodontal prevention/treatment and for reducing oral health disparities. Full article

Klebsiella pneumoniae, a major opportunistic pathogen, causes severe infections in both community and healthcare settings, especially in intensive care units (ICUs), where multidrug-resistant (MDR) strains, such as carbapenem-resistant K. pneumoniae (CRKP), pose significant treatment challenges. The rise in hypervirulent K. pneumoniae (hvKP) with enhanced virulence factors complicates management further. The ST11 clone, prevalent in China, exhibits both resistance and virulence traits, contributing to hospital outbreaks. ICU patients, particularly those with comorbidities or prior antibiotic exposure, are at higher risk. Treatment is complicated by limited antibiotic options and the increasing prevalence of polymicrobial infections, which involve resistant pathogens like Pseudomonas aeruginosa and Acinetobacter baumannii. Combination therapies offer some promise, but mortality rates remain high, and resistance to last-resort antibiotics is growing. Infection control measures and personalized treatment plans are critical, alongside the urgent need for vaccine development to combat the rising threat of K. pneumoniae, particularly in vulnerable populations. Effective management requires improved diagnostic tools, antimicrobial stewardship, and innovative treatment strategies to reduce the burden of this pathogen, especially in resource-limited settings. This review aims to provide a comprehensive analysis of the virulence, resistance, and epidemiological risks of K. pneumoniae in ICUs over the past decade, highlighting the ongoing challenges and the need for continued efforts to combat this growing threat. Full article

Carbohydrate-binding modules (CBMs) are essential virulence factors in phytopathogens, particularly the extensively studied members from the CBM50 gene family, which are known as lysin motif (LysM) effectors and which play crucial roles in plant–pathogen interactions. However, the function of CBM50 in Tilletia horrida has yet to be fully studied. In this study, we identified seven CBM50 genes from the T. horrida genome through complete sequence analysis and functional annotation. Their phylogenetic relationships, conserved motifs, promoter elements, and expression profile were further analyzed. The phylogenetic analysis indicated that these seven ThCBM50 genes were divided into three groups, and close associations were observed among proteins with similar protein motifs. The promoter cis-acting elements analysis revealed that these ThCBM50 proteins may be involved in the regulation of the phytohormones, stress response, and meristem expression of the host plant during T. horrida infection. The transcriptome data indicated that four ThCBM50 genes were upregulated during T. horrida infection. We further found that ThCBM50_1 caused cell death in the leaves of Nicotiana benthamiana, and its signal peptide (SP) had a secreting function. These results offer important clues that highlight the features of T. horrida CBM50 family proteins and set the stage for further investigation into their roles in the interactions between T. horrida and rice. Full article

Buchnera aphidicola, an obligate endosymbiont of most aphid species, can influence aphids’ host adaptability through amino acid metabolism, potentially mediating biotype differentiation. However, its role in the biotype differentiation of Sitobion avenae remains unclear. To address this issue, six S. avenae biotypes were tested in this study. Buchnera abundance varied among biotypes fed on different wheat/barley varieties (i.e., Zhong 4 wumang, 186-TM12-34; Dulihuang, Zaoshu No.3, Xiyin No.2). The reduction in Buchnera abundance through antibiotic (rifampicin) treatment altered the virulence of five S. avenae biotypes. Based on transcriptome analysis, the differential expression of three genes (i.e., LeuB, TrpE, and IlvD) related to leucine, tryptophan, isoleucine, and valine metabolism was detected between different biotypes. Principal component analysis showed that leucine and tryptophan deficiencies most significantly impacted nymph development duration and aphid fecundity. Additionally, a neighbor-joining phylogenetic tree indicated the genetic differentiation of Buchnera among different biotypes. These results suggest Buchnera-mediated amino acid metabolism is correlated with biotype differentiation in S. avenae, although the precise mechanisms by which Buchnera influences this differentiation require further investigation. This study can offer a theoretical basis for the development of resistant crops, leading to the sustainable control of this aphid and reduced reliance on chemical insecticides. Full article

This study investigates the prevalence of Vibrio spp. in seafood from supermarkets and fish markets in Berlin, Germany. A total of 306 seafood samples, including shrimp and mussels, were bought from supermarkets between March 2023 and January 2024. Samples were analysed using the ISO standard method and multiplex PCR to identify V. parahaemolyticus, V. alginolyticus, V. cholerae and V. vulnificus. The results indicated an overall Vibrio spp. prevalence of 56%. Among the positive samples, the most prevalent species found was V. parahaemolyticus (58%), followed by V. alginolyticus (42%), V. cholerae non-O1/non-O139 (25%), and V. vulnificus (4%). Samples obtained from supermarkets exhibited a lower prevalence (50%) than those received from fish markets (91%). Virulence genes such as ctxA, tdh, or trh were not detected in the respective Vibrio species. Nevertheless, the high prevalence underscores the need and urgency of continuous seafood surveillance. Full article

Porcine reproductive and respiratory syndrome (PRRS), characterized by reproductive failures in breeding pigs and respiratory diseases in growing pigs, is a widespread and challenging disease. The agent, PRRSV, is a single-strand RNA virus that is undergoing continuous mutation and evolution, resulting in the global spread of multiple strains with different genetic characteristics and variable antigens. There are currently no effective measures to eradicate PRRS, and vaccination is crucial for controlling the disease. At present, various types of vaccine are available or being studied, including inactivated vaccines, modified live virus (MLV) vaccines, vector vaccines, subunit vaccines, DNA vaccines, RNA vaccines, etc. MLV vaccines have been widely used to control PRRSV infection for more than 30 years since they were first introduced in North America in 1994, and have shown a certain efficacy. However, there are safety and efficacy issues such as virulence reversion, recombination with field strains, and a lack of protection against heterologous strains, while other types of vaccine have their own advantages and disadvantages, making the eradication of PRRS a challenge. This article reviews the latest progress of these vaccines in the prevention and control of PRRS and provides scientific inspiration for developing new strategies for the next generation of PRRS vaccines. Full article

Xanthomonas oryzae pv. oryzae (Xoo) is the causative agent of rice bacterial blight (RBB), resulting in substantial harvest losses and posing a challenge to maintaining a stable global supply. In this study, Xoo strains isolated from Shaoxing, Quzhou, and Taizhou, where RBB occurred most frequently in Zhejiang Province in 2019, were selected as the subjects of research. Three isolated pathogenic bacteria of ZXooS (from Shaoxing), ZXooQ (from Quzhou), and ZXooT (from Taizhou) were all identified as novel Xoo strains. These novel strains demonstrate greater virulence compared to Zhe173, the previous epidemic Xoo strain from Zhejiang Province. Subsequent genomic sequencing and analysis revealed that there existed significant differences in the genome sequence, especially in effector genes corresponding to some known rice resistance (R) genes between the novel strains and Zhe173. The sequence alignment of avirulent genes (effector genes) indicated that nucleic and amino acid sequences of AvrXa5, AvrXa7, AvrXa10, and AvrXa23 in the novel strains varied prominently from those in Zhe173. Interestingly, it seemed that only the genome of ZXooQ might contain the AvrXa3 gene. In addition, the phylogenetic analysis of 61 Xoo strains revealed that the novel strains were situated in a distinct evolutionary clade separate from Zhe173. These results here suggest that the emergence of novel Xoo strains may lead to resistance loss of some R genes used in commercial rice varieties, potentially serving as one of the factors leading to RBB resurgence in Zhejiang Province, China. Full article

Pathogenic fungi represent a diverse group of eukaryotic microorganisms that significantly impact human health and agriculture. In recent years, the role of epigenetic modifications, particularly histone modifications, in fungal pathobiology has emerged as a prominent area of interest. Among these modifications, methylation of histone H3 at lysine-4 (H3K4) has garnered considerable attention for its implications in regulating gene expression associated with diverse cellular processes. A body of literature has uncovered the pivotal roles of H3K4 methylation in multiple biological processes crucial for pathogenic adaptation in a wide range of fungal pathogens of humans and food crops. This review delves into the recent advancements in understanding the impact of H3K4 methylation/demethylation on fungal pathogenesis. We explore the roles of H3K4 methylation in various cellular processes, including fungal morphogenesis and development, genome stability and DNA repair, metabolic adaptation, cell wall maintenance, biofilm formation, antifungal drug resistance, and virulence. We also discuss the conservation of H3K4 methylation regulators and their potential as therapeutic targets to prevent fungal diseases. Collectively, this review underscores the intricate links between H3K4 methylation, fungal pathogenesis, and potential avenues for novel antifungal strategies. Full article

Due to the vulnerability of pepper (Capsicum spp.) and the virulence of tomato spotted wilt virus (TSWV), seasonal shortages and surges of prices are a challenge and thus threaten household income. Traditional bioassays for detecting TSWV, such as observation for symptoms and reverse transcription-PCR, are time-consuming, labor-intensive, and sometimes lack precision, highlighting the need for a faster and more reliable approach to plant disease assessment. Here, two imaging techniques—Red–Green–Blue (RGB) and hyperspectral imaging (using NDVI and wavelength intensities)—were compared with a bioassay method to study the incidence and severity of TSWV in different pepper accessions. The bioassay results gave TSWV an incidence from 0 to 100% among the accessions, while severity ranged from 0 to 5.68% based on RGB analysis. The normalized difference vegetative index (NDVI) scored from 0.21 to 0.23 for healthy spots on the leaf but from 0.14 to 0.19 for disease spots, depending on the severity of the damage. The peak reflectance of the disease spots on the leaves was identified in the visible light spectrum (430–470 nm) when spectral bands were studied in the broad spectrum (400.93–1004.5 nm). For the selected wavelength in the visible light spectrum, a high reflectance intensity of 340 to 430 was identified for disease areas, but between 270 and 290 for healthy leaves. RGB and hyperspectral imaging techniques can be recommended for precise and accurate detection and quantification of TSWV infection. Full article

Infectious bursal disease (IBD) is among the most impactful immunosuppressive diseases of poultry. Its agent, infectious bursal disease virus (IBDV), is prone to both mutation and reassortment, resulting in a remarkable variability. Traditionally, IBDV characterization relies on antigenicity and pathogenicity assessment, but multiple phylogenetic classifications have been recently proposed, whose implementation in molecular surveys helps generating informative and standardized epidemiological data. In the present study, the Algerian IBDV scenario was assessed based on the novel classification guidelines by sequencing portions of both genome segments. Seventy pools of bursal samples were collected in 2022–2023 in 11 districts of Northern Algeria, mostly from broiler flocks. Out of 55 (78.6%) positive flocks, 40 (57.1%) were infected by field strains, which were characterized as very virulent strains (genotype A3B2) and phylogenetically related to previously reported Algerian strains. Significant differences in the percentage of field infections were observed between vaccinated (25/52, 46.2%) and unvaccinated (14/17, 82.3%) groups, and also between birds immunized with live intermediate (13/20, 65.0%) and intermediate plus (10/28, 35.7%) vaccines. Nonetheless, the number of field strain detections suggests a high infectious pressure and the inadequacy of current vaccination efforts, demanding a reevaluation of control measures coupled with attentive monitoring activities. Full article

Proteolytic enzymes play key roles in living organisms. Because of their potentially destructive action of degrading other proteins, their activity must be very tightly controlled. The evolutionarily conserved proteins of the HtrA family are an excellent example illustrating strategies for regulating enzymatic activity, enabling protease activation in response to an appropriate signal, and protecting against uncontrolled proteolysis. Because HtrA homologs play key roles in the virulence of many Gram-negative bacterial pathogens, they are subject to intense investigation as potential therapeutic targets. Model HtrA proteins from bacterium Escherichia coli are allosteric proteins with reasonably well-studied properties. Binding of appropriate ligands induces very large structural changes in these enzymes, including changes in the organization of the oligomer, which leads to the acquisition of the active conformation. Properly coordinated events occurring during the process of HtrA activation ensure proper functioning of HtrA and, consequently, ensure fitness of bacteria. The aim of this review is to present the current state of knowledge on the structure and function of the exemplary HtrA family proteins from Gram-negative bacteria, including human pathogens. Special emphasis is paid to strategies for regulating the activity of these enzymes. Full article

Anthracocystis panici-leucophaei, causal agent of smut on Digitaria insularis (sourgrass), was evaluated as a biological control agent for this weed. Two types of inocula (teliospore and sporidia) were tested to assess its infectivity. The effects of teliospore and sporidia inoculations at different phenological stages of sourgrass were compared, as well as the potential of sporidia and teliospores in post-emergence sourgrass management. Virulence tests were conducted with the isolates obtained from D. insularis and evaluation of specificity of A. panici-leucophaei. Both teliospores and sporidia of A. panici-leucophaei are infective to D. insularis in three different phenological stages. Newly emerged plants with one pair of leaves are more sensitive to A. panici-leucophaei. Infection by A. panici-leucophaei inhibits the growth of sourgrass, decreasing several physiological parameters of D. insularis plants. The fungus produces systematic infection of sourgrass plants and may induce the formation of sori in a significant proportion of the plant panicles, partly castrating those plants. Among sixteen A. panici-peucophaei isolates tested, isolate 46 was the most virulent and inhibited the growth of sourgrass plants, and thus appears to have good potential as a biological control agent to be deployed against sourgrass. A. panici-leucophaei was demonstrated to be specific to D. insularis. Full article

Fusarium wilt disease severely constrains the global banana industry. The highly destructive disease is caused by Fusarium oxysporum f. sp. cubense, especially its virulent tropical race 4 (Foc TR4). Selenium (Se), a non-essential mineral nutrient in higher plants, is known to enhance plant resistance against several fungal pathogens. The experiments we conducted showed that selenium (≥10 mg/L) dramatically inhibited the growth of Foc TR4 mycelia and promoted plant growth. The further study we performed recorded a substantial reduction in the disease index (DI) of banana plants suffering from Foc TR4 when treated with selenium. The selenium treatments (20~160 mg/L) demonstrated significant control levels, with recorded symptom reductions ranging from 42.4% to 65.7% in both greenhouse and field trials. The DI was significantly negatively correlated with the total selenium content (TSe) in roots. Furthermore, selenium treatments enhanced the antioxidant enzyme activities of peroxidase (POD), polyphenol oxidase (PPO), and glutathione peroxidase (GSH-Px) in banana. After two applications of selenium (100 and 200 mg/plant) in the field, the TSe in banana pulps increased 23.7 to 25.9-fold and achieved the Se enrichment standard for food. The results demonstrate that selenium applications can safely augment root TSe levels, both reducing Fusarium wilt disease incidence and producing Se-enriched banana fruits. For the first time, this study has revealed that selenium can significantly reduce the damage caused by soil-borne pathogens in banana by increasing the activities of antioxidant enzymes and inhibiting fungal growth. Full article