Pathogen Interactions Research Articles

Development of a rapid and efficient system for CR genes identification based on hairy root transformation in Brassicaceae

Many economically important crops and vegetables belonging to the cruciferous family are heavily endangered by clubroot disease caused by Plasmodiophora brassicae infection. Breeding of clubroot resistant cultivars based on mapping and cloning of resistant genes is commonly regarded as the most cost-effective and efficient way to fight against this disease. The traditional way of R gene functional validation requires stable transformation that is both time- and labor-consuming. In this study, a rapid and efficient hairy-root transgenic protocol mediated by Agrobacterium rhizogenes was developed. The transformation positive rate was over 80% in Brassica napus showed by GUS reporter gene and this transformation only took 1/6 of the time compared with stable transformation. The system was applicable to different B. napus varieties and other cruciferous crops including Brassica rapa and Brassica oleracea. In particular, two known CR genes, CRA3.7.1 and CRA8.2.4 were used respectively, as example to show that the system works well for CR gene study combined with subsequent P. brassicae infection in B. napus. Most importantly, it works both in over-expression that led to disease resistance, as well as in RNAi which led to disease susceptible phenotype. Therefore, this system can be used in batch-wise identification of CR genes, and also offered the possibility of manipulating key genes within the P. brassicae genome that could improve our knowledge on host–pathogen interaction.

Lessons from COVID‐19: Aspects of prevention, therapeutics, and diagnostics against SARS‐CoV‐2 with special focus on JN.1 and XBB sublineages

AbstractThe end of second decade in the 21st century witnessed a prominent disease outbreak caused by the novel coronavirus SARS‐CoV‐2 (including most diverse omicron subvariants), where the death toll crossed the boundary of 6.9 million across the globe by December 19, 2023. All spheres of central dogma of molecular biology and host‒pathogen interaction was explored to find ways in diagnostics, isolation, curtailment, and therapy. Above all, diagnostics and therapeutics against COVID‐19 took an enormous jump, which needs to be evaluated for accuracy and feasibility and requires serious compilation for current and future generations. With the same objective, this review encompasses the diverse ways including prevention practiced and proposed during the handling of this pandemic across the globe. It involves the role of mutations in viruses and subsequent epitope mapping with potential immune escape mechanisms of SARS‐CoV‐2 variants including the conservancy of T‐cell epitopes has also been highlighted. The efficacy in antigen/antibody‐based diagnostics, RT‒PCR‐ and NGS‐based confirmation of pathogen presence, and imaging (X‐ray/CT‐scan) for symptoms and damage assessment has been thoroughly filtered. The possibility of errors in diagnostics and their cause and consequences have also been presented for the ease of readers and further improvisers.

Flow-through inactivation of pathogenic Escherichia coli by titanium suboxide reactive electrochemical membranes: Unlocking the coupled mechanics of electrochemical and subcellular alterations

Limited mass transfer controlled by diffusion and unexplored disinfection mechanisms at the subcellular alternation respond to different electrochemical reactions always obstacles the electrochemical disinfection decentralized water treatment. Here, a large-scale reactive electrode membrane composed of titanium suboxide (TiSO-REM) was pioneered for pathogen inactivation and mechanism exploration. Complete bacteria inactivation (>7.1 log reduction) was achieved after 20 min of electrolysis at 1440 L m−2 h−1 (LMH) and 15 mA cm−2. Electrostatic adsorption facilitated the interaction of pathogens with oxidants in the electrode boundary layer by enhancing the adhesion of Escherichia coli at anode surface, resulting in 25 % improvement in removal. Subcellular alternation of waterborne pathogens depended on specific electrochemical mechanisms. Direct electron transfer (DET) unbalanced intracellular metabolism by excessive intracellular reactive oxygen species accumulation. While more violent electro-generated •OH annihilated the whole cells with disorderly alternation which also effectively reduced the risk of bacterial regeneration with no bacterial resuscitation. The study also provides a universal model to develop sustainable technologies for pathogen inactivation and precise regulation of inactivation efficiency from a mechanistic perspective for a wide range of engineering applications like water disinfection and bio-safety control.

Study of fungal cell wall evolution through its monosaccharide composition: An insight into fungal species interacting with plants

Every fungal cell is encapsulated in a cell wall, essential for cell viability, morphogenesis, and pathogenesis. Most knowledge of the cell wall composition in fungi has focused on ascomycetes, especially human pathogens, but considerably less is known about early divergent fungal groups, such as species in the Zoopagomycota and Mucoromycota phyla. To shed light on evolutionary changes in the fungal cell wall, we studied the monosaccharide composition of the cell wall of 18 species including early diverging fungi and species in the Basidiomycota and Ascomycota phyla with a focus on those with pathogenic lifestyles and interactions with plants. Our data revealed that chitin is the most characteristic component of the fungal cell wall, and was found to be in a higher proportion in the early divergent groups. The Mucoromycota species possess few glucans, but instead have other monosaccharides such as fucose and glucuronic acid that are almost exclusively found in their cell walls. Additionally, we observed that hexoses (glucose, mannose and galactose) accumulate in much higher proportions in species belonging to Dikarya. Our data demonstrate a clear relationship between phylogenetic position and fungal cell wall carbohydrate composition and lay the foundation for a better understanding of their evolution and their role in plant interactions.

Integration of targeted metabolome and transcript profiling of Pseudomonas syringae-triggered changes in defence-related phytochemicals in oat plants

Main conclusionA gene-to-metabolite approach afforded new insights regarding defence mechanisms in oat plants that can be incorporated into plant breeding programmes for the selection of markers and genes related to disease resistance.Monitoring metabolite levels and changes therein can complement and corroborate transcriptome (mRNA) data on plant–pathogen interactions, thus revealing mechanisms involved in pathogen attack and host defence. A multi-omics approach thus adds new layers of information such as identifying metabolites with antimicrobial properties, elucidating metabolomic profiles of infected and non-infected plants, and reveals pathogenic requirements for infection and colonisation. In this study, two oat cultivars (Dunnart and SWK001) were inoculated with Pseudomonas syringae pathovars, pathogenic and non-pathogenic on oat. Following inoculation, metabolites were extracted with methanol from leaf tissues at 2, 4 and 6 days post-infection and analysed by multiple reaction monitoring (MRM) on a triple quadrupole mass spectrometer system. Relatedly, mRNA was isolated at the same time points, and the cDNA analysed by quantitative PCR (RT-qPCR) for expression levels of selected gene transcripts associated with avenanthramide (Avn) biosynthesis. The targeted amino acids, hydroxycinnamic acids and Avns were successfully quantified. Distinct cultivar-specific differences in the metabolite responses were observed in response to pathogenic and non-pathogenic strains. Trends in aromatic amino acids and hydroxycinnamic acids seem to indicate stronger activation and flux through these pathways in Dunnart as compared to SWK001. A positive correlation between hydroxycinnamoyl-CoA:hydroxyanthranilate N-hydroxycinnamoyl transferase (HHT) gene expression and the abundance of Avn A in both cultivars was documented. However, transcript profiling of selected genes involved in Avn synthesis did not reveal a clear pattern to distinguish between the tolerant and susceptible cultivars.Graphical abstract

Comparison of the Effect of Pruning on Plant Growth and Transcriptome Profiles in Different Tea Varieties

Although pruning contributes to the growth and development of new shoots, it is important to note that the growth potential and yield of tea varieties may differ after pruning due to genetic and environmental factors. In this experiment, 20 different varieties of tea plants were used to observe their potential for growth, shoot development, and other phenotypic indexes after pruning. The study aimed to determine the suitability of each variety for heavy pruning. It was concluded that there were obvious differences in tree strength and new growth after pruning of the different varieties, with ‘Zhongcha 302’ exhibiting the strongest growth and ‘Emei Wenchun’ showing the weakest growth. In order to understand the molecular mechanisms involved, a transcriptomic analysis was carried out on the two tea varieties. The results of the data indicate that the expression of CYP450 family was high in ‘Zhongcha 302’. In ‘Emei Wenchun’, the expression of NCED was higher than that in ‘Zhongcha 302’. The KEGG results indicate that pruning stimulates the expression of genes involved in phytohormone signalling and plant–pathogen interaction pathways in tea plants. The study offered scientific guidance for tea plant pruning suitability and preliminarily revealed the regulatory mechanism of new shoot growth in different tea plant varieties at the transcriptome level.

Pathogen-epithelium interactions and inflammatory responses in Salmonella Dublin infections using ileal monolayer models derived from adult bovine organoids

Salmonella enterica serovar Dublin (S. Dublin) is an important enteric pathogen affecting cattle and poses increasing public health risks. Understanding the pathophysiology and host–pathogen interactions of S. Dublin infection are critical for developing effective control strategies, yet studies are hindered by the lack of physiologically relevant in vitro models. This study aimed to generate a robust ileal monolayer derived from adult bovine organoids, validate its feasibility as an in vitro infection model with S. Dublin, and evaluate the epithelial response to infection. A stable, confluent monolayer with a functional epithelial barrier was established under optimized culture conditions. The model’s applicability for studying S. Dublin infection was confirmed by documenting intracellular bacterial invasion and replication, impacts on epithelial integrity, and a specific inflammatory response, providing insights into the pathogen-epithelium interactions. The study underscores the utility of organoid-derived monolayers in advancing our understanding of enteric infections in livestock and highlights implications for therapeutic strategy development and preventive measures, with potential applications extending to both veterinary and human medicine. The established bovine ileal monolayer offers a novel and physiologically relevant in vitro platform for investigating enteric pathogen-host interactions, particularly for pathogens like S. Dublin.

Experimental Infection Models and Their Usefulness for White Spot Syndrome Virus (WSSV) Research in Shrimp

White spot syndrome virus (WSSV) is marked as one of the most economically devastating pathogens in shrimp aquaculture worldwide. Infection of cultured shrimp can lead to mass mortality (up to 100%). Although progress has been made, our understanding of WSSV’s infection process and the virus–host–environment interaction is far from complete. This in turn hinders the development of effective mitigation strategies against WSSV. Infection models occupy a crucial first step in the research flow that tries to elucidate the infectious disease process to develop new antiviral treatments. Moreover, since the establishment of continuous shrimp cell lines is a work in progress, the development and use of standardized in vivo infection models that reflect the host–pathogen interaction in shrimp is a necessity. This review critically examines key aspects of in vivo WSSV infection model development that are often overlooked, such as standardization, (post)larval quality, inoculum type and choice of inoculation procedure, housing conditions, and shrimp welfare considerations. Furthermore, the usefulness of experimental infection models for different lines of WSSV research will be discussed with the aim to aid researchers when choosing a suitable model for their research needs.

A screen for Plasmodium falciparum sporozoite surface protein binding to human hepatocyte surface receptors identifies novel host–pathogen interactions

BackgroundSporozoite invasion of hepatocytes is an essential step in the Plasmodium life-cycle and has similarities, at the cellular level, to merozoite invasion of erythrocytes. In the case of the Plasmodium blood-stage, efforts to identify host–pathogen protein–protein interactions have yielded important insights including vaccine candidates. In the case of sporozoite-hepatocyte invasion, the host–pathogen protein–protein interactions involved are poorly understood.MethodsTo gain a better understanding of the protein–protein interaction between the sporozoite ligands and host receptors, a systematic screen was performed. The previous Plasmodium falciparum and human surface protein ectodomain libraries were substantially extended, resulting in the creation of new libraries comprising 88 P. falciparum sporozoite protein coding sequences and 182 sequences encoding human hepatocyte surface proteins. Having expressed recombinant proteins from these sequences, a plate-based assay was used, capable of detecting low affinity interactions between recombinant proteins, modified for enhanced throughput, to screen the proteins for interactions. The novel interactions identified in the screen were characterized biochemically, and their essential role in parasite invasion was further elucidated using antibodies and genetically manipulated Plasmodium parasites.ResultsA total of 7540 sporozoite-hepatocyte protein pairs were tested under conditions capable of detecting interactions of at least 1.2 µM KD. An interaction between the human fibroblast growth factor receptor 4 (FGFR4) and the P. falciparum protein Pf34 is identified and reported here, characterizing its affinity and demonstrating the blockade of the interaction by reagents, including a monoclonal antibody. Furthermore, further interactions between Pf34 and a second P. falciparum rhoptry neck protein, PfRON6, and between human low-density lipoprotein receptor (LDLR) and the P. falciparum protein PIESP15 are identified.Conditional genetic deletion confirmed the essentiality of PfRON6 in the blood-stage, consistent with the important role of this protein in parasite lifecycle. Pf34 was refractory to attempted genetic modification. Antibodies to Pf34 abrogated the interaction and had a modest effect upon sporozoite invasion into primary human hepatocytes.ConclusionPf34 and PfRON6 may be members of a functionally important invasion complex which could be a target for future interventions. The modified interaction screening assay, protein expression libraries and P. falciparum mutant parasites reported here may be a useful tool for protein interaction discovery and antigen candidate screening which could be of wider value to the scientific community.

Quantifying innate immune response of an insect host challenged by non‐replicative immune inducers

AbstractNon‐linear immune response is one of the causes of multi‐stability of infection outcomes. In order to avoid the uncertainty caused by multi‐stability in experiments, one needs to quantitatively measure immune response and other traits as well. Here, we took a quantitative approach, which combines mathematical model and time‐series data, to measure the immune response of the Tenebrio moliter challenged by non‐replicative immune inducers. The results showed that the host immunity that characterized by in‐vitro bacterial killing rapidly mounted after immune challenging, then slowly declined to an undetectable level within 100 h. We then quantified the immunity at 15 h after challenging. The results showed that immune response was non‐linearly correlated with the titter of inducer, which fits well to a Hill‐like function. Our results have verified the non‐linear immune response with respect to amount of invading pathogens and may also help to rigorously test the concepts and theories in host–pathogen interaction, such as resistance and tolerance.

Association between periodontitis and dental caries: a systematic review and meta-analysis

ObjectivesRecent evidence suggested a link between periodontitis (PD) and dental caries, but the trends and nature of this association remained unclear. The overall aim of this study was to critically assess the correlation of two disorders.MethodsA comprehensive search was conducted within the PUBMED and EMBASE databases including grey literatures up to July 5th, 2023. The Newcastle–Ottawa scale was used to qualitatively evaluate the risk of bias.ResultsOverall, 18 studies were included. In terms of caries risk in PD patients, the prevalence of caries was increased by PD (OR = 1.57, 95%CI:1.20–2.07), both in crown (OR = 1.03, 95%CI:1.01–1.05) and root caries (OR = 2.10, 95%CI:1.03–4.29). Odds of caries were also raised by PD severity (OR moderate = 1.38, 95%CI:1.15–1.66; OR severe = 2.14, 95%CI:1.74–2.64). Besides, patients with PD exhibited a higher mean number of decayed, missing and filled teeth (DMFT) and decayed and filled root teeth (DFR) [weighted mean difference (WMD)DMFT = 0.87, 95%CI: -0.03–1.76; WMDDFR = 1.13, 95%CI: 0.48–1.78]. Likewise, patients with caries had an elevated risk of PD (OR = 1.79, 95%CI:1.36–2.35). However, Streptococcus mutans, one of the main pathogens of caries, was negatively correlated with several main pathogens of periodontitis.ConclusionsThis study indicated a positive correlation between dental caries and periodontitis clinically, while the two disease-associated pathogens were antagonistic.Clinical relevanceFurther research, including clinical cohort studies and mechanisms of pathogens interaction is needed on this link for better prevention and treatment of PD and caries. In addition, innovative prevention strategies need to be developed and incorporated in dental practices to prevent these two highly prevalent oral diseases.

Multi‐omics approaches reveal inflammatory response and intestinal damage mediated by sRNA SaaS during Salmonella invasion in mice

AbstractSalmonella Enteritidis is a foodborne enteric pathogen that infects humans and animals, and bacterial small RNAs (sRNAs) have been found to play critical roles in the virulence of Salmonella. However, the specific mechanism by which sRNAs contribute to the host–pathogen interaction in the intestine remains unclear. In this study, a combination of transcriptomic and proteomic analysis was used to investigate the effect of a particular sRNA known as Salmonella adhesive‐associated sRNA (SaaS) on the intestinal damage induced by Salmonella. The results revealed that SaaS sRNA could suppress the host's inflammatory response through various gene sets, mainly including tumor necrosis factor (TNF)‐α signaling via NF‐κB, IL‐6 JAK‐STAT3 signaling, and interferon gamma responses. This suppressive effect was further confirmed by ELISA analysis, which showed the lowest levels of TNF‐α, IL‐6, and interferon gamma (IFN‐γ). Meanwhile, the work has identified several crucial factors, peptidoglycan recognition protein short, transferrin receptor protein 1, and corticosteroid 11‐beta‐dehydrogenase isozyme 2, that are specifically targeted by SaaS to regulate inflammatory response, neutrophils activity, and diseases. Furthermore, combining hematologic analysis and correlation analysis, this study demonstrated that SaaS led to a decrease in the percentage of neutrophils and revealed a strong correlation between the three crucial factors and various markers of inflammation and intestinal barrier function. These findings provide a comprehensive understanding of how SaaS sRNA modulates Salmonella invasion in the animal intestine and further present a strategy on controlling foodborne Salmonella based on the new targets, sRNAs.

Bacterial community of ticks (Acari: Ixodidae) and mammals from Arauca, Colombian Orinoquia

Ticks are obligate hematophagous ectoparasites of vertebrates and are relevant worldwide due to the number of bacterial and other pathogens they can transmit. To date, the knowledge about the microorganisms that ticks harbor and transmit to their hosts is incipient. In this study, 24 samples of mammals belonging to four taxonomic orders and ticks of the genera Amblyomma and Rhipicephalus from the Orinoco region of Colombia were analyzed to described and compare the bacterial microbiome. Genetic extraction was performed, and the V3–V4 region of the 16S rRNA gene was amplified by PCR. Libraries were created, and those samples with adequate quality indices were sequenced using Illumina MiSeq technology. Bacterial taxonomic assignment analyses were conducted through Amplicon Sequence Variants (ASVs) and Operational Taxonomic Units (OTUs). The results correspond to 16 samples that passed the quality filters, with 3218 OTUs (415 families). Although a considerable number of unknown bacteria was found, Enterobacteriaceae, Beijerinckiaceae, Moraxellaceae, and Burkholderiaceae are the most prevalent families, and the presence of the genera Coxiella, Escherichia-Shigella, Enterobacter, which can harbor pathogenic species was confirmed. In individuals of Amblyomma mixtum found actively feeding on Hydrochoerus hydrochaeris, bacteria of the genera Escherichia-Shigella and Enterobacter were documented. Similarly, Rhipicephalus microplus found actively feeding on Odocoileus virginianus cariacou shared Escherichia-Shigella. Ralstonia was shared among the blood samples of H. hydrochaeris, while Anaplasma and Eubacterium were shared in blood and liver samples of O. v. cariacou. Shared bacteria between A. mixtum and R. microplus included Bacillus, Coxiella, and Escherichia-Shigella. The results highlight the need of additional studies in other natural regions of Colombia and other American countries where tick-borne diseases have been detected. Likewise, the recorded data are the first at the level of bacterial communities in ticks of the family Ixodidae and provide valuable knowledge for the understanding host-tick and pathogen interactions.

The novel fish miRNA, Soc-miR-118, functions as a negative regulator in NF-κB–mediated inflammation by targeting IL-6 in teleost fish

Inflammation is initiated as a protective response of the organism to remove invading bacterial and initiate the healing process. Prolonged inflammation and excessive production of inflammatory cytokines lead to inflammatory disorders or autoimmune diseases. Thus, different layers of negative regulators are needed to achieve balances between protective immunity and inflammatory pathology. Accumulating evidences show that miRNAs act as significant and multifunctional regulators involved in regulating networks of host-pathogen interactions. However, the functions and mechanisms of miRNAs in directly targeting and regulating inflammatory cytokines remains largely unknown in lower vertebrates. In this study, we report a novel miRNA, Soc-miR-118, identified from Sciaenops ocellatus, which plays a negative role in antibacterial immunity by regulating Interleukin-6 (IL-6). Specifically, we found that Soc-miR-118 directly targets IL-6 and suppresses the production of inflammatory cytokines through the NF-κB signaling pathway, thereby avoiding excessive inflammatory response. Particularly, the mechanism by which Soc-miR-118 regulates IL-6 expression also exist in other fish, suggesting that the miRNA in fish has evolutionarily conserved regulatory systems. The collective results that Soc-miR-118 acts as a negative regulator involved in host antibacterial immunity through directly regulating inflammatory cytokines, will greatly enrich the intricate networks of host–pathogen interaction in lower vertebrates.

Host–pathogen interaction between the African fig fly, Zaprionus indianus, and its external mycobiome under laboratory conditions

AbstractThe African fig fly, Zaprionus indianus Gupta (Diptera: Drosophilidae), is an ecologically diverse pest species that interacts with and feeds on various microbial pathogens including bacteria and yeast found in decomposing fruits. However, the interaction of Z. indianus with its microbial community and microbial pathogens is obscure. To determine the presence of fungal pathogens, we collected wild Z. indianus from the northwestern part of the Indian subcontinent. Based on molecular identification and phylogenetic analysis, Debaryomyces hansenii (Zopf) Lodder & Kreger‐van Rij (isolate ziha1) was the most commonly observed fungus associated with Z. indianus. Furthermore, we identified two more opportunistic fungal pathogens: Aspergillus flavus Link (isolate zias2), and Pichia kudriavzevii Boidin, Pignal & Besson (isolate zibd3). The interaction of isolated fungi with Z. indianus was evaluated in terms of larval mortality, adult emergence, and fecundity. Debaryomyces hansenii ziha1 resulted in 90% emergence rate for adults, and did not cause significant mortality in the larval stage. In contrast, A. flavus zias2 and P. kudriavzevii zibd3 showed a significant reduction in fecundity and caused 99% and 74% larval mortality of Z. indianus, respectively. In the laboratory oviposition preference assay, mated females of Z. indianus preferred D. hansenii ziha1 supplemented food with a positive oviposition index compared to the uninfected control and compared to food infected with P. kudriavzevii zibd3 or A. flavus zias2. These findings underscore Z. indianus' potential to act as a reservoir for both symbiotic and pathogenic fungal species, some of which may be further harnessed for effective fruit fly pest control strategies.

Transcriptome Analysis and Validation of Anthracnose Resistance Genes in Walnut Varieties

Anthracnose is extremely detrimental to walnut production, because it seriously affects its yield. Therefore, this study aimed to identify anthracnose resistance genes in walnuts, to lay the foundation for cultivating novel anthracnose-resistant walnut varieties. In this study, the fruits of walnut varieties “Qinyou 1” and “Qinyou 2”, exhibiting relatively weak resistance to anthracnose, were used for transcriptome sequencing and identifying differentially expressed genes (DEGs). Thereafter, we used a quantitative real-time polymerase chain reaction to verify the reliability of the transcriptome data using the walnut varieties Qinyou 1, Qinyou 2, Qinyou 3, Liaohe 1, and Diamond 1. We identified 6326 DEGs post-infection in Qinyou 1, of which 3065 were upregulated and 3261 were downregulated. We also found 2055 DEGs (969 upregulated and 1086 downregulated genes) in the two varieties, after 6 days of anthracnose infection. Based on GO and KEGG enrichment analyses of the transcriptome data, we noted that the DEGs were primarily involved in metabolic processes, cell composition, cell structure, catalytic activity, and binding activity. Furthermore, KEGG functional enrichment analysis showed that the amino acid biosynthesis pathway and plant–pathogen interaction may be activated under anthracnose infection. We also noted that the expression levels of anthracnose resistance genes in different walnut varieties were significantly different. Thus, the findings of this study provide important genetic resources and molecular markers for the cultivation of novel anthracnose-resistant walnut varieties.

Recognition of the inducible, secretory small protein OsSSP1 by the membrane receptor OsSSR1 and the co-receptor OsBAK1 confers rice resistance to the blast fungus

The plant apoplast, which serves as the frontline battleground for long-term host–pathogen interactions, harbors a wealth of disease resistance resources. However, the identification of the disease resistance proteins in the apoplast is relatively lacking. In this study, we identified the rice secretory protein OsSSP1 (Oryza sativa secretory small protein 1). OsSSP1 can be secreted into the plant apoplast, and both in vitro treatment of recombinant OsSSP1 and overexpression of OsSSP1 in rice can trigger plant immune response. The expression of OsSSP1 is suppressed significantly during Magnaporthe oryzae infection in susceptible rice Taibei 309, and OsSSP1-overexpressing lines all show strong resistance to M. oryzae. Combining the knockout and overexpression results, we found that OsSSP1 positively regulates plant immunity in response to fungal infection. Moreover, the recognition and immune response triggered by OsSSP1 depend on an uncharacterized transmembrane OsSSR1 (secretory small protein receptor 1) and the key co-receptor OsBAK1, since most of the induced immune response and resistance are lost in the absence of OsSSR1 or OsBAK1. Intriguingly, the OsSSP1 protein is relatively stable and can still induce plant resistance after 1 week of storage in the open environment, and exogenous OsSSP1 treatment for a 2-week period did not affect rice yield. Collectively, our study reveals that OsSSP1 can be secreted into the apoplast and percepted by the plasma membrane receptors OsSSR1 and OsBAK1 during fungal infection, thereby triggering the immune response to enhance plant resistance to M. oryzae. These findings providing novel resources and potential strategies for crop breeding and disease control.

Insights into the cumulative effect of Colletotrichum gloeosporioides and Fusarium acutatum causing anthracnose-twister disease complex of onion

Colletotrichum is an important plant pathogenic fungi that causes anthracnose/-twister disease in onion. This disease was prevalent in the monsoon season from August to November months and the symptoms were observed in most of the fields. This study aimed to investigate the pathogenicity and cumulative effect, if any of Colletotrichum gloeosporioides and Fusarium acutatum. The pot experiment was laid out to identify the cause responsible for inciting anthracnose-twister disease, whether the Colletotrichum or Fusarium or both, or the interaction of pathogens and GA3. The results of the pathogenicity test confirmed that C. gloeosporioides and F. acutatum are both pathogenic. C. gloeosporioides caused twisting symptoms independently, while F.acutatum independently caused only neck elongation. The independent application of GA3 did not produce any symptoms, however, increased the plant height. The combined treatment of C. gloeosporioides and F. acutatum caused twisting, which enhanced upon interaction with GA3 application giving synergistic effect. The acervuli were found in lesions infected with C. gloeosporioides after 8 days of inoculation on the neck and leaf blades. Symptoms were not observed in untreated control plants. Koch's postulates were confirmed by reisolating the same pathogens from the infected plants.

Bacterial diversity dominates variable macrophage responses of tuberculosis patients in Tanzania

The Mycobacterium tuberculosis complex (MTBC) comprises nine human-adapted lineages that differ in their geographical distribution. Local adaptation of specific MTBC genotypes to the respective human host population has been invoked in this context. We aimed to assess if bacterial genetics governs MTBC pathogenesis or if local co-adaptation translates into differential susceptibility of human macrophages to infection by different MTBC genotypes. We generated macrophages from cryopreserved blood mononuclear cells of Tanzanian tuberculosis patients, from which the infecting MTBC strains had previously been phylogenetically characterized. We infected these macrophages ex vivo with a phylogenetically similar MTBC strain (“matched infection”) or with strains representative of other MTBC lineages (“mismatched infection”). We found that L1 infections resulted in a significantly lower bacterial burden and that the intra-cellular replication rate of L2 strains was significantly higher compared the other MTBC lineages, irrespective of the MTBC lineage originally infecting the patients. Moreover, L4-infected macrophages released significantly greater amounts of TNF-α, IL-6, IL-10, MIP-1β, and IL-1β compared to macrophages infected by all other strains. While our results revealed no measurable effect of local adaptation, they further highlight the strong impact of MTBC phylogenetic diversity on the variable outcome of the host–pathogen interaction in human tuberculosis.

Fungal Necrotrophic Interaction: A Case Study of Seed Immune Response to a Seed-Borne Pathogen

Seeds play a vital role in the perpetuation of plant species, both in natural environments and agriculture. However, they often face challenges from biotic stresses, such as seed-borne pathogenic fungi. The transgenerational transmission of these seed-borne fungi, along with their dissemination during seed commercialization, can contribute to the emergence of global epidemic diseases, resulting in substantial economic losses. Despite the recognized impact of seed-borne pathogens on agriculture, our understanding of seed–pathogen interactions remains limited. This review establishes parallels between the current state of knowledge regarding seed responses to pathogen interactions and well-established plant defense models, primarily derived from typical physiological conditions observed during leaf infections. Examining fragmented results from various pathosystems, this review seeks to offer a comprehensive overview of our current understanding of interactions during seed development and germination. The necrotrophic interactions in Brassicaceae are described using recent transcriptomic and genetic studies focused on the Arabidopsis/Alternaria pathosystem, which illustrates original response pathways in germinating seeds that markedly differ from the general concept of plant–pathogen interactions. The co-existence of regulatory mechanisms affecting both seed resistance and susceptibility, potentially promoting fungal colonization, is examined. The vulnerable response during germination emerges as a crucial consideration in the context of sustainable plant health management in agriculture.