Project description:Plant pathogens can cause serious diseases that impact global agriculture1. Understanding how the plant immune system naturally restricts pathogen infection holds a key to sustainable disease control in modern agricultural practices. However, despite extensive studies into the molecular and genetic basis of plant defense against pathogens since the 1950s2,3, one of the most fundamental questions in plant pathology remains unanswered: how resistant plants halt pathogen growth during immune activation. In the case of bacterial infections, a major bottleneck is an inability to determine the global bacterial transcriptome and metabolic responses in planta. Here, we developed an innovative pipeline that allows for in planta high-resolution bacterial transcriptome analysis with RNA-Seq, using the model plant Arabidopsis thaliana and the foliar bacterial pathogen Pseudomonas syringae. We examined a total of 27 combinations of plant immunity and bacterial virulence mutants to gain an unprecedented insight into the bacterial transcriptomic responses during plant immunity. We were able to identify specific bacterial transcriptomic signatures that are linked to bacterial inhibition during two major forms of plant immunity: pattern-triggered immunity and effector-triggered immunity. Among them, regulation of a P. syringae sigma factor gene, involved in iron regulation and an unknown process(es), was found to play a causative role in bacterial restriction during plant immunity. This study unlocked the enigmatic mechanisms of bacterial growth inhibition during plant immunity; results have broad basic and practical implications for future study of plant diseases.
Project description:Plant pathogens can cause serious diseases that impact global agriculture1. Understanding how the plant immune system naturally restricts pathogen infection holds a key to sustainable disease control in modern agricultural practices. However, despite extensive studies into the molecular and genetic basis of plant defense against pathogens since the 1950s2,3, one of the most fundamental questions in plant pathology remains unanswered: how resistant plants halt pathogen growth during immune activation. In the case of bacterial infections, a major bottleneck is an inability to determine the global bacterial transcriptome and metabolic responses in planta. Here, we developed an innovative pipeline that allows for in planta high-resolution bacterial transcriptome analysis with RNA-Seq, using the model plant Arabidopsis thaliana and the foliar bacterial pathogen Pseudomonas syringae. We examined a total of 27 combinations of plant immunity and bacterial virulence mutants to gain an unprecedented insight into the bacterial transcriptomic responses during plant immunity. We were able to identify specific bacterial transcriptomic signatures that are linked to bacterial inhibition during two major forms of plant immunity: pattern-triggered immunity and effector-triggered immunity. Among them, regulation of a P. syringae sigma factor gene, involved in iron regulation and an unknown process(es), was found to play a causative role in bacterial restriction during plant immunity. This study unlocked the enigmatic mechanisms of bacterial growth inhibition during plant immunity; results have broad basic and practical implications for future study of plant diseases.
Project description:Seaweeds may represent immunostimulants that could be used as health-promoting fish feed components thereby offering an alternative for the use of antibiotics. This study was performed to gain insights into the immunomodulatory effects of dietary seaweeds in Atlantic salmon. Specifically tested were 10% inclusion levels of Laminaria digitata (SW1) and a commercial blend of seaweeds (Oceanfeed®) (SW2) against a fishmeal based control diet (FMC). Differences between groups were assessed in growth, feed conversion ratio (FCR) and blood parameters hematocrit (Hct) and hemoglobin (Hb). After a LPS challenge of fish representing each of the three groups, RNAseq was performed on head kidneys to determine transcriptomic differences in response to the immune activation, to our knowledge for the first time in fish in this context. Atlantic salmon fed with dietary seaweeds showed slightly higher FCRs and more homogenous growth but in general no major differences in performance in comparison with fishmeal fed fish. RNAseq resulted in ~154 million reads which were mapped against a NCBI Salmo salar reference and against a de novo assembled Salmo salar reference for analyses of expression of immune genes and ontology of immune processes among the 87,600 cDNA contigs. The dietary seaweeds provoked a more efficient immune response which involved more efficient identification of the infection site, and processing and presentation of antigens. More specifically, chemotaxis and the chemokine-mediated signaling pathway with involvement of genes such as C-C motif chemokine 19 were improved and the defense response to Gram-positive bacterium reduced. The predicted integrin alpha-2-like gene had by far the highest up-regulated expression and may therefore represent a key marker gene of the LPS immune response in salmonids. Specific Laminaria digita effects included reduction of the cytokine-mediated signalling pathway as indicated by the cytokine macrophage migration inhibitory factor, and interferon-gamma-mediated signalling as indicated by STAT1 and the gamma-interferon-inducible lysosomal thiol reductase precursor. Highly upregulated and specific for this diet was the expression of Major histocompatibility complex class I-related gene protein. The commercial blend of seaweeds caused more differential expression than Laminaria digita and improved immune processes such as receptor-mediated endocytosis, inflammatory response, cell adhesion and response to lipopolysaccharide. Particularly expression of many important immune receptors was up-regulated illustrating increased responsiveness. NF-kappa-B inhibitor alpha is an important gene that marked the difference between both seaweed diets as Laminaria digita inhibits the production of this cytokine while the blend of seaweeds stimulates it. It can be concluded that replacing fishmeal partly with seaweeds such as Laminaria digita can have important modulatory effects on the immune capacity of Atlantic salmon resulting in a more efficient immune response.
Project description:Porphyra/Pyropia seaweeds are promising sources for functional foods development, offering a rich macro- and micronutrient profiles. In New Zealand (NZ), endemic Porphyra/Pyropia species (karengo), exhibit considerable variability driven by geography, seasonality, and climate, which may influence their nutritional quality. Despite their use as traditional foods, the NZ Porphyra/Pyropia remain underutilized commercially, in part due to the lack of biomolecular characterisation, particularly their bioactive protein components, hindering evidence-based species selection for seaweed farming commercialisation and functional food development. This study presents the first proteomic characterization of three NZ Porphyra/Pyropia species: Pyropia virididentata, Pyropia cinnamomea, and Porphyra GRB complex. Mass spectrometry-based proteomics analysis identified differences in the phycobiliprotein composition among the species, with the Porphyra GRB complex containing higher levels of phycocyanin. Using the protein sequence information, in silico gastrointestinal digestion analysis predicted that phycobiliproteins from NZ Porphyra/Pyropia seaweeds can potentially release bioactive peptides capable of inhibiting angiotensin-converting enzyme (ACE) and dipeptidyl peptidase-IV (DPP-IV) activities. Sequence-based allergenicity prediction indicated possible cross-reactivity between NZ Porphyra/Pyropia β-phycoerythrin and β-phycocyanin against the β-phycocyanin allergen from spirulina, which is associated with a low incidence of allergy. Proximate analysis revealed that NZ Porphyra/Pyropia seaweeds have high protein (26–30.2 %) and carbohydrate (48.3–50.9 %) contents, and low fat and free sugar levels. Amino acid profiling further showed that NZ Porphyra/Pyropia seaweeds are relatively rich in sulphur-containing amino acids and umami-associated amino acids. Overall, these findings highlight the potential of NZ Porphyra/Pyropia seaweeds as a novel plant-based protein source for functional food applications.
Project description:We have recently shown that the coprophilous model mushroom Coprinopsis cinerea transcribes a broad array of genes encoding defense proteins in the vegetative mycelium and fruiting bodies that target bacterial competitors and animal predators challenging the respective tissues of this fungus. In addition, we have demonstrated in previous work that two nematotoxic defense proteins from Coprinopsis, CGL1 and CGL2, were induced in vegetative mycelium challenged with the predatory nematode Aphelenchus avenae; however, the specificity and broadness of this response remained unclear. In order to resolve these issues, we sequenced the poly(A)-positive transcriptome of vegetative mycelium of C. cinerea confronted with nematode predation, hyphal mechanical damage or bacterial co-culture.
Project description:To investigate the effect of soy peptides on gut microial composition during juvenile social isolation, group-house (GH) and social isolation (SI) mice were fed a diet consisting of soy peptides or a control diet for 4 weeks post-weaning. We then performed microbial community analysis using data obtained from bacterial 16S rRNA gene sequencing in the fecal samples of 4 mice groups (control diet-fed GH, soy peptide-diet fed GH, control diet-fed SI, and soy peptide-diet fed SI mice).