Project description:Microbial consortia consist of a multitude of prokaryotic and eukaryotic microorganisms. Their interaction is critical for the functioning of ecosystems. Until now, there is limited knowledge about the communication signals determining the interaction between bacteria and fungi and how they influence microbial consortia. Here, we discovered that bacterial low molecular weight arginine-derived polyketides trigger the production of distinct natural products in fungi. These compounds are produced by actinomycetes found on all continents except Antarctica and are characterized by an arginine-derived positively charged group linked to a linear or cyclic polyene moiety. Producer bacteria can be readily isolated from soil as well as fungi that decode the signal and respond with the biosynthesis of natural products. Both arginine-derived polyketides and the compounds produced by fungi in response shape microbial interactions.
2023-06-16 | PXD033242 | Pride
Project description:Rhizosphere carbon turnover facilitated by cross-kingdom microbial interactions
Project description:Disrupted interactions between host and intestinal bacteria are implicated in the development of colorectal cancer (CRC). However, the functional impacts of these inter-kingdom interactions remain poorly defined. To examine this interplay, we performed small RNA sequencing on the stool of from germ-free (GF) and gnotobiotic ApcMin/+;Il10-/- mice associated with microbes from biofilm-positive human CRC tumor (BT) and biofilm-negative healthy (BX) tissues. revealed a group of significant differentially expressed miRNAs specific to BT compared to BX associated ApcMin/+;Il10-/- mice and several miRNAs that correlated with bacterial genera abundances. Our findings suggest complex interactions within bacterial communities affecting host-derived miRNA and CRC development.
Project description:Environmental microbial triggers shape the development and functionality of the immune system. Alveolar macrophages (AMs), tissue-resident macrophages of the lungs, are in constant and direct contact with inhaled particles and microbes. Such exposures likely impact AM reactivity to subsequent challenges by immunological imprinting mechanisms referred to as trained immunity. Here, we investigated whether a ubiquitous microbial compound has the potential to induce AM training in vivo. We showed that intranasal exposure to ambient amounts of lipopolysaccharide (LPS) protected mice from bacterial pneumonia six days later and discovered a pronounced AM memory response, characterized by enhanced reactivity upon pneumococcal challenge. Exploring the mechanistic basis of AM training, we identified a critical role of type 1 interferon signaling and found that trained AMs displayed a substantially modulated metabolite and lipid composition. Inhibition of fatty acid oxidation and glutaminolysis significantly attenuated the training effect, suggesting a key function of metabolic rewiring in LPS-induced AM memory. Collectively, our findings demonstrate the profound impact of ambient microbial exposure on pulmonary immune memory and highlight tissue-specific features of trained immunity.
Project description:Disrupted interactions between host and intestinal bacteria are implicated in the development of colorectal cancer (CRC). However, the functional impacts of these inter-kingdom interactions remain poorly defined. To examine this interplay, we performed mouse and microbiota RNA-sequencing on colon tissue from germ-free (GF) and gnotobiotic ApcMin/+;Il10-/- mice associated with microbes from biofilm-positive human CRC tumor (BT) and biofilm-negative healthy (BX) tissues. The bacteria in BT mice differentially expressed >2,900 genes related to bacterial secretion, virulence and biofilms, but only affected 62 host genes. Importantly, the bacterial communities from BT mice were transmissible and carcinogenic when administered to a new GF ApcMin/+;Il10-/- cohort, maintaining a set of 13 bacterial genera. Our findings suggest complex interactions within bacterial communities affecting bacterial composition and CRC development.
Project description:The identification of processes activated by specific microbes during microbiota colonization of plant roots has been hampered by technical constraints in metatranscriptomics. These include lack of reference genomes, high representation of host or microbial rRNA sequences in datasets, or difficulty to experimentally validate gene functions. Here, we recolonized germ-free Arabidopsis thaliana with a synthetic, yet representative root microbiota comprising 106 genome-sequenced bacterial and fungal isolates. We used multi-kingdom rRNA depletion, deep RNA-sequencing and read mapping against reference microbial genomes to analyse the in-planta metatranscriptome of abundant colonizers. We identified over 3,000 microbial genes that were differentially regulated at the soil-root interface. Translation and energy production processes were consistently activated in planta, and their induction correlated with bacterial strains’ abundance in roots. Finally, we used targeted mutagenesis to show that several genes consistently induced by multiple bacteria are required for root colonization in one of the abundant bacterial strains (a genetically tractable Rhodanobacter). Our results indicate that microbiota members activate strain-specific processes but also common gene sets to colonize plant roots.
Project description:Extracellular vesicles (EVs) have been extensively studied in animal cells, and play an important role in cell-to-cell communications. Emerging evidence shows that EVs also act as important agents in plant-microbe interactions. However, the mechanisms by which EVs mediate cross-kingdom interactions between plants and microbial pathogens remain largely elusive. Here, proteomic analyses of soybean root rot pathogen Phytophthora sojae EVs identified tetraspanin family proteins, PsTET1 and PsTET3, that can be recognized by Nicotiana benthamiana to trigger plant immune responses. PsTET1 and PsTET3 were redundantly required for the full virulence of P. sojae. Further analyses revealed that the large extracellular loop (EC2) of PsTET3 is the key region recognized by N. benthamiana and also by Glycine max, and that recognition depends on the plant receptor-like kinase BAK1. TET proteins from oomycete and fungal plant pathogens could be recognized by N. benthamiana and induce immune responses. However, plant-derived TET proteins failed to do so, due to the divergent sequences of the final 16 amino acids of EC2, which ultimately makes plants distinguish self and non-self EVs, triggering active defenses against pathogenic eukaryotes.
Project description:MicroRNAs (miRNAs) are small non-coding RNAs between 18-23nts in size which regulate the translation and stability of target mRNAs. miRNAs are present in dietary plants and are conventionally thought to be degraded during the gastrointestinal digestion process. Recent reports suggest that a few dietary microRNAs may exhibit resistance to this process, enter systemic circulation and exert biological effects on animal physiology, currently known as cross-kingdom regulation. However, such horizontal transfer of miRNAs via different kingdoms is highly likely for miRNAs that are present intrinsic extracellular vesicles which increases their bioavailability. These vesicular structures from plants are known as Exosome-like nanovesicles (ENV). ENVs have been isolated from several edible plants. ENV-derived miRNAs are probably more bioavailable and are spontaneously absorbed in intestinal epithelium to suppress target transcripts in human/microbial/viral kingdoms. Such cross-kingdom regulation exhibited by ENV-miRNAs, if properly investigated and validated, may aid in the development of non-toxic and cost-effective therapeutics to treat human diseases. In this line, we purified ENVs from four edible plants (Soy bean, ginger, amla and turmeric). Small RNA population from these ENVs were isolated and profiled through small RNA sequencing to identify ENV-associated miRNAs enriched in each species.
Project description:Genome scale metabolic model of Drosophila gut microbe Acetobacter fabarum
Abstract -
An important goal for many nutrition-based microbiome studies is to identify the metabolic function of microbes in complex microbial communities and their impact on host physiology. This research can be confounded by poorly understood effects of community composition and host diet on the metabolic traits of individual taxa. Here, we investigated these multiway interactions by constructing and analyzing metabolic models comprising every combination of five bacterial members of the Drosophila gut microbiome (from single taxa to the five-member community of Acetobacter and Lactobacillus species) under three nutrient regimes. We show that the metabolic function of Drosophila gut bacteria is dynamic, influenced by community composition, and responsive to dietary modulation. Furthermore, we show that ecological interactions such as competition and mutualism identified from the growth patterns of gut bacteria are underlain by a diversity of metabolic interactions, and show that the bacteria tend to compete for amino acids and B vitamins more frequently than for carbon sources. Our results reveal that, in addition to fermentation products such as acetate, intermediates of the tricarboxylic acid (TCA) cycle, including 2-oxoglutarate and succinate, are produced at high flux and cross-fed between bacterial taxa, suggesting important roles for TCA cycle intermediates in modulating Drosophila gut microbe interactions and the potential to influence host traits. These metabolic models provide specific predictions of the patterns of ecological and metabolic interactions among gut bacteria under different nutrient regimes, with potentially important consequences for overall community metabolic function and nutritional interactions with the host.IMPORTANCE Drosophila is an important model for microbiome research partly because of the low complexity of its mostly culturable gut microbiota. Our current understanding of how Drosophila interacts with its gut microbes and how these interactions influence host traits derives almost entirely from empirical studies that focus on individual microbial taxa or classes of metabolites. These studies have failed to capture fully the complexity of metabolic interactions that occur between host and microbe. To overcome this limitation, we reconstructed and analyzed 31 metabolic models for every combination of the five principal bacterial taxa in the gut microbiome of Drosophila This revealed that metabolic interactions between Drosophila gut bacterial taxa are highly dynamic and influenced by cooccurring bacteria and nutrient availability. Our results generate testable hypotheses about among-microbe ecological interactions in the Drosophila gut and the diversity of metabolites available to influence host traits.