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1.
BMC Genomics ; 25(1): 153, 2024 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-38326788

RESUMO

BACKGROUND: Russian wheat aphid (Diuraphis noxia Kurd.) is a severe pest to wheat, and even though resistance varieties are available to curb this pest, they are becoming obsolete with the development of new virulent aphid populations. Unlike many other aphids, D noxia only harbours a single endosymbiont, Buchnera aphidicola. Considering the importance of Buchnera, this study aimed to elucidate commonalities and dissimilarities between various hosts, to better understand its distinctiveness within its symbiotic relationship with D. noxia. To do so, the genome of the D. noxia's Buchnera was assembled and compared to those of other aphid species that feed on diverse host species. RESULTS: The overall importance of several features such as gene length and percentage GC content was found to be critical for the maintenance of Buchnera genes when compared to their closest free-living relative, Escherichia coli. Buchnera protein coding genes were found to have percentage GC contents that tended towards a mean of ~ 26% which had strong correlation to their identity to their E. coli homologs. Several SNPs were identified between different aphid populations and multiple isolates of Buchnera were confirmed in single aphids. CONCLUSIONS: Establishing the strong correlation of percentage GC content of protein coding genes and gene identity will allow for identifying which genes will be lost in the continually shrinking Buchnera genome. This is also the first report of a parthenogenically reproducing aphid that hosts multiple Buchnera strains in a single aphid, raising questions regarding the benefits of maintaining multiple strains. We also found preliminary evidence for post-transcriptional regulation of Buchnera genes in the form of polyadenylation.


Assuntos
Afídeos , Buchnera , Animais , Buchnera/genética , Buchnera/metabolismo , Escherichia coli , Afídeos/genética , Afídeos/metabolismo , Regulação da Expressão Gênica , Dieta , Simbiose/genética
2.
J Math Biol ; 88(2): 24, 2024 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-38308102

RESUMO

The evolution of mutualism between host and symbiont communities plays an essential role in maintaining ecosystem function and should therefore have a profound effect on their range expansion dynamics. In particular, the presence of mutualistic symbionts at the leading edge of a host-symbiont community should enhance its propagation in space. We develop a theoretical framework that captures the eco-evolutionary dynamics of host-symbiont communities, to investigate how the evolution of resource exchange may shape community structure during range expansion. We consider a community with symbionts that are mutualistic or parasitic to various degrees, where parasitic symbionts receive the same amount of resource from the host as mutualistic symbionts, but at a lower cost. The selective advantage of parasitic symbionts over mutualistic ones is increased with resource availability (i.e. with host density), promoting mutualism at the range edges, where host density is low, and parasitism at the population core, where host density is higher. This spatial selection also influences the speed of spread. We find that the host growth rate (which depends on the average benefit provided by the symbionts) is maximal at the range edges, where symbionts are more mutualistic, and that host-symbiont communities with high symbiont density at their core (e.g. resulting from more mutualistic hosts) spread faster into new territories. These results indicate that the expansion of host-symbiont communities is pulled by the hosts but pushed by the symbionts, in a unique push-pull dynamic where both the host and symbionts are active and tightly-linked players.


Assuntos
Ecossistema , Parasitos , Animais , Simbiose , Reprodução
3.
Nature ; 626(7998): 271-279, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38326590

RESUMO

Mitochondria retain bacterial traits due to their endosymbiotic origin, but host cells do not recognize them as foreign because the organelles are sequestered. However, the regulated release of mitochondrial factors into the cytosol can trigger cell death, innate immunity and inflammation. This selective breakdown in the 2-billion-year-old endosymbiotic relationship enables mitochondria to act as intracellular signalling hubs. Mitochondrial signals include proteins, nucleic acids, phospholipids, metabolites and reactive oxygen species, which have many modes of release from mitochondria, and of decoding in the cytosol and nucleus. Because these mitochondrial signals probably contribute to the homeostatic role of inflammation, dysregulation of these processes may lead to autoimmune and inflammatory diseases. A potential reason for the increased incidence of these diseases may be changes in mitochondrial function and signalling in response to such recent phenomena as obesity, dietary changes and other environmental factors. Focusing on the mixed heritage of mitochondria therefore leads to predictions for future insights, research paths and therapeutic opportunities. Thus, whereas mitochondria can be considered 'the enemy within' the cell, evolution has used this strained relationship in intriguing ways, with increasing evidence pointing to the recent failure of endosymbiosis being critical for the pathogenesis of inflammatory diseases.


Assuntos
Inflamação , Mitocôndrias , Modelos Biológicos , Simbiose , Humanos , Doenças Autoimunes/etiologia , Doenças Autoimunes/metabolismo , Doenças Autoimunes/patologia , Dieta/efeitos adversos , Homeostase , Inflamação/etiologia , Inflamação/metabolismo , Inflamação/patologia , Mitocôndrias/metabolismo , Mitocôndrias/patologia , Mitocôndrias/fisiologia , Proteínas Mitocondriais/metabolismo , Ácidos Nucleicos/metabolismo , Obesidade/complicações , Obesidade/metabolismo , Obesidade/patologia , Fosfolipídeos/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Simbiose/fisiologia , Animais
4.
Int J Mol Sci ; 25(3)2024 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-38339080

RESUMO

Nitrogen fixation, occurring through the symbiotic relationship between legumes and rhizobia in root nodules, is crucial in sustainable agriculture. Nodulation and soybean production are influenced by low levels of phosphorus stress. In this study, we discovered a MADS transcription factor, GmAGL82, which is preferentially expressed in nodules and displays significantly increased expression under conditions of phosphate (Pi) deficiency. The overexpression of GmAGL82 in composite transgenic plants resulted in an increased number of nodules, higher fresh weight, and enhanced soluble Pi concentration, which subsequently increased the nitrogen content, phosphorus content, and overall growth of soybean plants. Additionally, transcriptome analysis revealed that the overexpression of GmAGL82 significantly upregulated the expression of genes associated with nodule growth, such as GmENOD100, GmHSP17.1, GmHSP17.9, GmSPX5, and GmPIN9d. Based on these findings, we concluded that GmAGL82 likely participates in the phosphorus signaling pathway and positively regulates nodulation in soybeans. The findings of this research may lay the theoretical groundwork for further studies and candidate gene resources for the genetic improvement of nutrient-efficient soybean varieties in acidic soils.


Assuntos
Fósforo , Nodulação , Fósforo/metabolismo , Nodulação/genética , Nódulos Radiculares de Plantas/metabolismo , Fixação de Nitrogênio/genética , Simbiose , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo
5.
BMC Plant Biol ; 24(1): 103, 2024 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-38331718

RESUMO

BACKGROUND: The establishment of mycorrhizal relationships between a fungus and a plant typically enhances nutrient and water uptake for the latter while securing a carbon source for the fungus. However, under a particular set of environmental conditions, such as low availability of light and abundant nutrients in the soil, the resources invested in the maintenance of the fungi surpass the benefits obtained by the host. In those cases, facultative mycorrhizal plants are capable of surviving without symbiosis. Facultative mycorrhization in ferns has been overlooked until now. The present study measured the response of Struthiopteris spicant L. Weiss, and its root-associated fungi to different levels of light and nutrient availability in terms of growth, mycorrhizal presence, and leaf nutrient content. This fern species exhibits a great tolerance to variable light, nutrient, and pH conditions, and it has been found with and without mycorrhizae. We conducted a greenhouse experiment with 80 specimens of S. spicant and three factors (Light, Phosphorus, and Nitrogen) resulting in eight treatments. RESULTS: We found a significant influence of the factor light on fungal community composition, plant biomass, and nutrient accumulation. Departing from a lack of colonization at the initial stage, plants showed a remarkable increment of more than 80% in the arbuscular mycorrhizal fungi (AMF) richness and abundance in their roots when grown under high light conditions, compared with the ones in low light. We also observed an upward trend of C:P and C:N ratios and the above- and belowground biomass production when AMF abundance increased. Furthermore, the compositional analysis of the whole fungal communities associated with S. spicant roots revealed clear differences among low-light and high-light treatments. CONCLUSIONS: This study is the first to investigate the importance of light and nutrient availability in determining fern-AMF relationships. We confirmed that Struthiopteris spicant is a facultative mycorrhizal plant. The composition and diversity of AMF found in the roots of this fern are strongly influenced by light and less by nutrient conditions. Our study shows that ferns respond very sensitively to changes in environmental factors, leading to shifts in the associated mycorrhizal communities.


Assuntos
Gleiquênias , Micorrizas , Raízes de Plantas , Micorrizas/fisiologia , Simbiose , Solo/química , Microbiologia do Solo
6.
Sci Rep ; 14(1): 3231, 2024 02 08.
Artigo em Inglês | MEDLINE | ID: mdl-38332146

RESUMO

Advances in our understanding of symbiotic stability have demonstrated that microorganisms are key to understanding the homeostasis of obligate symbioses. Fungus-gardening ants are excellent model systems for exploring how microorganisms may be involved in symbiotic homeostasis as the host and symbionts are macroscopic and can be easily experimentally manipulated. Their coevolutionary history has been well-studied; examinations of which have depicted broad clade-to-clade specificity between the ants and fungus. Few studies hitherto have addressed the roles of microbiomes in stabilizing these associations. Here, we quantified changes in microbiome structure as a result of experimentally induced horizontal exchange of symbionts. This was done by performing cross-fostering experiments forcing ants to grow novel fungi and comparing known temporally unstable (undergoing dysbiosis) and stable combinations. We found that fungus-gardening ants alter their unstable, novel garden microbiomes into configurations like those found in native gardens. Patterns of dysbiosis/symbiosis appear to be predictable in that two related species with similar specificity patterns also show similar patterns of microbial change, whereas a species with more relaxed specificity does not show such microbiome change or restructuring when growing different fungi. It appears that clade-to-clade specificity patterns are the outcomes of community-level interactions that promote stability or cause symbiotic collapse.


Assuntos
Formigas , Microbiota , Animais , Jardinagem , Formigas/microbiologia , Simbiose , Disbiose , Fungos , Filogenia
7.
Commun Biol ; 7(1): 171, 2024 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-38347162

RESUMO

Microbial communities at the airway mucosal barrier are conserved and highly ordered, in likelihood reflecting co-evolution with human host factors. Freed of selection to digest nutrients, the airway microbiome underpins cognate management of mucosal immunity and pathogen resistance. We show here the initial results of systematic culture and whole-genome sequencing of the thoracic airway bacteria, identifying 52 novel species amongst 126 organisms that constitute 75% of commensals typically present in heathy individuals. Clinically relevant genes encode antimicrobial synthesis, adhesion and biofilm formation, immune modulation, iron utilisation, nitrous oxide (NO) metabolism and sphingolipid signalling. Using whole-genome content we identify dysbiotic features that may influence asthma and chronic obstructive pulmonary disease. We match isolate gene content to transcripts and metabolites expressed late in airway epithelial differentiation, identifying pathways to sustain host interactions with microbiota. Our results provide a systematic basis for decrypting interactions between commensals, pathogens, and mucosa in lung diseases of global significance.


Assuntos
Bactérias , Mucosa , Humanos , Mucosa/microbiologia , Bactérias/genética , Simbiose , Imunidade nas Mucosas , Genômica
8.
Sci Rep ; 14(1): 3646, 2024 02 13.
Artigo em Inglês | MEDLINE | ID: mdl-38351312

RESUMO

The distribution of symbiotic scleractinian corals is driven, in part, by light availability, as host energy demands are partially met through translocation of photosynthate. Physiological plasticity in response to environmental conditions, such as light, enables the expansion of resilient phenotypes in the face of changing environmental conditions. Here we compared the physiology, morphology, and taxonomy of the host and endosymbionts of individual Madracis pharensis corals exposed to dramatically different light conditions based on colony orientation on the surface of a shipwreck at 30 m depth in the Bay of Haifa, Israel. We found significant differences in symbiont species consortia, photophysiology, and stable isotopes, suggesting that these corals can adjust multiple aspects of host and symbiont physiology in response to light availability. These results highlight the potential of corals to switch to a predominantly heterotrophic diet when light availability and/or symbiont densities are too low to sustain sufficient photosynthesis, which may provide resilience for corals in the face of climate change.


Assuntos
Antozoários , Animais , Antozoários/fisiologia , Fotossíntese , Processos Heterotróficos , Simbiose/fisiologia , Israel , Recifes de Corais
9.
FEMS Microbiol Ecol ; 100(3)2024 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-38364305

RESUMO

The holobiont Holobiont theory is more than 80 years old, while the importance of microbial communities for plant holobionts was already identified by Lorenz Hiltner more than a century ago. Both concepts are strongly supported by results from the new field of microbiome research. Here, we present ecological and genetic features of the plant holobiont that underpin principles of a shared governance between hosts and microbes and summarize the relevance of plant holobionts in the context of global change. Moreover, we uncover knowledge gaps that arise when integrating plant holobionts in the broader perspective of the holobiome as well as one and planetary health concepts. Action is needed to consider interacting holobionts at the holobiome scale, for prediction and control of microbiome function to improve human and environmental health outcomes.


Assuntos
Microbiota , Saúde Única , Humanos , Idoso de 80 Anos ou mais , Simbiose , Plantas
10.
J Environ Manage ; 353: 120167, 2024 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-38308995

RESUMO

The quality of soil containing heavy metals (HMs) around nonferrous metal mining areas is often not favorable for plant growth. Three types of plant growth promoting rhizobacteria (PGPR)-assisted ryegrass were examined here to treat Cd, Pb, and Zn contaminated soil collected from a nonferrous metal smelting facility. The effects of PGPR-assisted plants on soil quality, plant growth, and the migration and transformation of HMs were evaluated. Results showed that inter-root inoculation of PGPR to ryegrass increased soil redox potential, urease, sucrase and acid phosphatase activities, microbial calorimetry, and bioavailable P, Si, and K content. Inoculation with PGPR also increased aboveground parts and root length, P, Si, and K contents, and antioxidant enzyme activities. The most significant effect was that the simultaneous inoculation of all three PGPRs increased the ryegrass extraction (%) of Cd (59.04-79.02), Pb (105.56-157.13), and Zn (27.71-40.79), compared to CK control (without fungi). Correspondingly, the inter-root soil contents (%) of total Cd (39.94-57.52), Pb (37.59-42.17), and Zn (34.05-37.28) were decreased compared to the CK1 control (without fungi and plants), whereas their bioavailability was increased. Results suggest that PGPR can improve soil quality in mining areas, promote plant growth, transform the fraction of HMs in soil, and increase the extraction of Cd, Pb, and Zn by ryegrass. PGPR is a promising microbe-assisted phytoremediation strategy that can promote the re-greening of vegetation in the mining area while remediating HMs pollution.


Assuntos
Lolium , Metais Pesados , Poluentes do Solo , Cádmio , Chumbo , Simbiose , Solo/química , Metais Pesados/análise , Bactérias , Biodegradação Ambiental , Zinco , Poluentes do Solo/análise
11.
Ecol Lett ; 27(2): e14379, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38361469

RESUMO

Mutualisms have driven the evolution of extraordinary structures and behavioural traits, but their impact on traits beyond those directly involved in the interaction remains unclear. We addressed this gap using a highly evolutionarily replicated system - epiphytes in the Rubiaceae forming symbioses with ants. We employed models that allow us to test the influence of discrete mutualistic traits on continuous non-mutualistic traits. Our findings are consistent with mutualism shaping the pace of morphological evolution, strength of selection and long-term mean of non-mutualistic traits in function of mutualistic dependency. While specialised and obligate mutualisms are associated with slower trait change, less intimate, facultative and generalist mutualistic interactions - which are the most common - have a greater impact on non-mutualistic trait evolution. These results challenge the prevailing notion that mutualisms solely affect the evolution of interaction-related traits via stabilizing selection and instead demonstrate a broader role for mutualisms in shaping trait evolution.


Assuntos
Formigas , Evolução Biológica , Animais , Simbiose , Plantas/genética
12.
Ecol Lett ; 27(2): e14374, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38361467

RESUMO

Generalists are thought to adapt to broader ecological conditions compared to less flexible specialists. However, few studies have systematically tested what ecological or life-history traits are associated with organisms' ecological flexibility. Here, we used stony corals to test the relative effects of host traits and ecological factors on corals' flexibility to form photosymbioses with algae. We analysed data from 211 stony coral species to test if coral's geographic distribution, depth range, symbiont transmission mode or colony morphology predict coral-algal flexibility. We report a novel positive correlation between coral-algal flexibility and coral species' geographic range. Symbiont transmission mode was also a predictor of flexibility, albeit the result is less robust against sampling bias. Coral depth range and morphology did not show significant effects. We highlight that host-symbiont dispersal abilities, interactions and evolutionary histories likely contribute to the observed patterns. We urge conservation efforts to consider the ecological implications of coral-algal flexibility.


Assuntos
Antozoários , Dinoflagelados , Animais , Simbiose , Evolução Biológica , Adaptação Fisiológica , Recifes de Corais
13.
ISME J ; 18(1)2024 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-38365239

RESUMO

Coral microhabitats are colonized by a myriad of microorganisms, including diverse bacteria which are essential for host functioning and survival. However, the location, transmission, and functions of individual bacterial species living inside the coral tissues remain poorly studied. Here, we show that a previously undescribed bacterial symbiont of the coral Pocillopora acuta forms cell-associated microbial aggregates (CAMAs) within the mesenterial filaments. CAMAs were found in both adults and larval offspring, suggesting vertical transmission. In situ laser capture microdissection of CAMAs followed by 16S rRNA gene amplicon sequencing and shotgun metagenomics produced a near complete metagenome-assembled genome. We subsequently cultured the CAMA bacteria from Pocillopora acuta colonies, and sequenced and assembled their genomes. Phylogenetic analyses showed that the CAMA bacteria belong to an undescribed Endozoicomonadaceae genus and species, which we propose to name Candidatus Sororendozoicomonas aggregata gen. nov sp. nov. Metabolic pathway reconstruction from its genome sequence suggests this species can synthesize most amino acids, several B vitamins, and antioxidants, and participate in carbon cycling and prey digestion, which may be beneficial to its coral hosts. This study provides detailed insights into a new member of the widespread Endozoicomonadaceae family, thereby improving our understanding of coral holobiont functioning. Vertically transmitted, tissue-associated bacteria, such as Sororendozoicomonas aggregata may be key candidates for the development of microbiome manipulation approaches with long-term positive effects on the coral host.


Assuntos
Antozoários , Gammaproteobacteria , Animais , Antozoários/microbiologia , Filogenia , RNA Ribossômico 16S/genética , Bactérias/genética , Metagenoma , Gammaproteobacteria/genética , Recifes de Corais , Simbiose
14.
ISME J ; 18(1)2024 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-38365249

RESUMO

In Burkholderia-Riptortus symbiosis, the host bean bug Riptortus pedestris harbors Burkholderia symbionts in its symbiotic organ, M4 midgut, for use as a nutrient source. After occupying M4, excess Burkholderia symbionts are moved to the M4B region, wherein they are effectively digested and absorbed. Previous studies have shown that M4B has strong symbiont-specific antibacterial activity, which is not because of the expression of antimicrobial peptides but rather because of the expression of digestive enzymes, mainly cathepsin L protease. However, in this study, inhibition of cathepsin L activity did not reduce the bactericidal activity of M4B, indicating that there is an unknown digestive mechanism that renders specifically potent bactericidal activity against Burkholderia symbionts. Transmission electron microscopy revealed that the lumen of symbiotic M4B was filled with a fibrillar matter in contrast to the empty lumen of aposymbiotic M4B. Using chromatographic and electrophoretic analyses, we found that the bactericidal substances in M4B existed as high-molecular-weight (HMW) complexes that were resistant to protease degradation. The bactericidal HMW complexes were visualized on non-denaturing gels using protein- and polysaccharide-staining reagents, thereby indicating that the HMW complexes are composed of proteins and polysaccharides. Strongly stained M4B lumen with Periodic acid-Schiff (PAS) reagent in M4B paraffin sections confirmed HMW complexes with polysaccharide components. Furthermore, M4B smears stained with Periodic acid-Schiff revealed the presence of polysaccharide fibers. Therefore, we propose a key digestive mechanism of M4B: bacteriolytic fibers, polysaccharide fibers associated with digestive enzymes such as cathepsin L, specialized for Burkholderia symbionts in Riptortus gut symbiosis.


Assuntos
Burkholderia , Heterópteros , Animais , Catepsina L/metabolismo , Catepsina L/farmacologia , Simbiose/fisiologia , Ácido Periódico/metabolismo , Ácido Periódico/farmacologia , Insetos , Heterópteros/microbiologia , Bactérias , Polissacarídeos/metabolismo , Burkholderia/fisiologia
15.
World J Microbiol Biotechnol ; 40(3): 101, 2024 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-38366186

RESUMO

Xenorhabdus, known for its symbiotic relationship with Entomopathogenic nematodes (EPNs), belongs to the Enterobacteriaceae family. This dual-host symbiotic nematode exhibits pathogenic traits, rendering it a promising biocontrol agent against insects. Our prior investigations revealed that Xenorhabdus stockiae HN_xs01, isolated in our laboratory, demonstrates exceptional potential in halting bacterial growth and displaying anti-tumor activity. Subsequently, we separated and purified the supernatant of the HN_xs01 strain and obtained a new compound with significant inhibitory activity on tumor cells, which we named XNAE. Through LC-MS analysis, the mass-to-nucleus ratio of XNAE was determined to be 254.24. Our findings indicated that XNAE exerts a time- and dose-dependent inhibition on B16 and HeLa cells. After 24 h, its IC50 for B16 and HeLa cells was 30.178 µg/mL and 33.015 µg/mL, respectively. Electron microscopy revealed conspicuous damage to subcellular structures, notably mitochondria and the cytoskeleton, resulting in a notable reduction in cell numbers among treated tumor cells. Interestingly, while XNAE exerted a more pronounced inhibitory effect on B16 cells compared to HeLa cells, it showed no discernible impact on HUVEC cells. Treatment of B16 cells with XNAE induced early apoptosis and led to cell cycle arrest in the G2 phase, as evidenced by flow cytometry analysis. The impressive capability of X. stockiae HN_xs01 in synthesizing bioactive secondary metabolites promises to significantly expand the reservoir of natural products. Further exploration to identify the bioactivity of these compounds holds the potential to shed light on their roles in bacteria-host interaction. Overall, these outcomes underscore the promising potential of XNAE as a bioactive compound for tumor treatment.


Assuntos
Nematoides , Xenorhabdus , Animais , Humanos , Xenorhabdus/metabolismo , Células HeLa , Nematoides/microbiologia , Enterobacteriaceae , Simbiose
16.
J Evol Biol ; 37(2): 162-170, 2024 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-38366251

RESUMO

Host-parasite coevolution is mediated by genetic interactions between the antagonists and may lead to reciprocal adaptation. In the black bean aphid, Aphis fabae fabae, resistance to parasitoids can be conferred by the heritable bacterial endosymbiont Hamiltonella defensa. H. defensa has been shown to be variably protective against different parasitoid species, and different genotypes of the black bean aphid's main parasitoid Lysiphlebus fabarum. However, these results were obtained using haphazard combinations of laboratory-reared insect lines with different origins, making it unclear how representative they are of natural, locally (co)adapted communities. We therefore comprehensively sampled the parasitoids of a natural A. f. fabae population and measured the ability of the five most abundant species to parasitize aphids carrying the locally prevalent H. defensa haplotypes. H. defensa provided resistance only against the dominant parasitoid L. fabarum (70% of all parasitoids), but not against less abundant parasitoids, and resistance to L. fabarum acted in a genotype-specific manner (G × G interactions between H. defensa and L. fabarum). These results confirm that strong species- and genotype-specificity of symbiont-conferred resistance is indeed a hallmark of wild A. f. fabae populations, and they are consistent with symbiont-mediated adaptation of aphids to the parasitoids posing the highest risk.


Assuntos
Afídeos , Vespas , Animais , Afídeos/genética , Afídeos/microbiologia , Vespas/genética , Interações Hospedeiro-Parasita/genética , Simbiose , Enterobacteriaceae
17.
PLoS Comput Biol ; 20(2): e1011860, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38335232

RESUMO

The complex eukaryotic cell resulted from a merger between simpler prokaryotic cells, yet the role of the mitochondrial endosymbiosis with respect to other eukaryotic innovations has remained under dispute. To investigate how the regulatory challenges associated with the endosymbiotic state impacted genome and network evolution during eukaryogenesis, we study a constructive computational model where two simple cells are forced into an obligate endosymbiosis. Across multiple in silico evolutionary replicates, we observe the emergence of different mechanisms for the coordination of host and symbiont cell cycles, stabilizing the endosymbiotic relationship. In most cases, coordination is implicit, without signaling between host and symbiont. Signaling only evolves when there is leakage of regulatory products between host and symbiont. In the fittest evolutionary replicate, the host has taken full control of the symbiont cell cycle through signaling, mimicking the regulatory dominance of the nucleus over the mitochondrion that evolved during eukaryogenesis.


Assuntos
Evolução Biológica , Simbiose , Simbiose/genética , Células Eucarióticas/metabolismo , Células Procarióticas/metabolismo , Eucariotos/genética , Filogenia
18.
ISME J ; 18(1)2024 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-38366166

RESUMO

Soil biocrusts are characterized by the spatial self-organization of resident microbial populations at small scales. The cyanobacterium Microcoleus vaginatus, a prominent primary producer and pioneer biocrust former, relies on a mutualistic carbon (C) for nitrogen (N) exchange with its heterotrophic cyanosphere microbiome, a mutualism that may be optimized through the ability of the cyanobacterium to aggregate into bundles of trichomes. Testing both environmental populations and representative isolates, we show that the proximity of mutualistic diazotroph populations results in M. vaginatus bundle formation orchestrated through chemophobic and chemokinetic responses to gamma-aminobutyric acid (GABA) /glutamate (Glu) signals. The signaling system is characterized by: a high GABA sensitivity (nM range) and low Glu sensitivity (µM to mM), the fact that GABA and Glu are produced by the cyanobacterium as an autoinduction response to N deficiency, and by the presence of interspecific signaling by heterotrophs in response to C limitation. Further, it crucially switches from a positive to a negative feedback loop with increasing GABA concentration, thus setting maximal bundle sizes. The unprecedented use of GABA/Glu as an intra- and interspecific signal in the spatial organization of microbiomes highlights the pair as truly universal infochemicals.


Assuntos
Microbiota , Solo , Simbiose , Fixação de Nitrogênio , Microbiologia do Solo
19.
Toxins (Basel) ; 16(2)2024 02 17.
Artigo em Inglês | MEDLINE | ID: mdl-38393187

RESUMO

Entomopathogenic nematodes from the genus Steinernema (Nematoda: Steinernematidae) are capable of causing the rapid killing of insect hosts, facilitated by their association with symbiotic Gram-negative bacteria in the genus Xenorhabdus (Enterobacterales: Morganellaceae), positioning them as interesting candidate tools for the control of insect pests. In spite of this, only a limited number of species from this bacterial genus have been identified from their nematode hosts and their insecticidal properties documented. This study aimed to perform the genome sequence analysis of fourteen Xenorhabdus strains that were isolated from Steinernema nematodes in Argentina. All of the strains were found to be able of killing 7th instar larvae of Galleria mellonella (L.) (Lepidoptera: Pyralidae). Their sequenced genomes harbour 110 putative insecticidal proteins including Tc, Txp, Mcf, Pra/Prb and App homologs, plus other virulence factors such as putative nematocidal proteins, chitinases and secondary metabolite gene clusters for the synthesis of different bioactive compounds. Maximum-likelihood phylogenetic analysis plus average nucleotide identity calculations strongly suggested that three strains should be considered novel species. The species name for strains PSL and Reich (same species according to % ANI) is proposed as Xenorhabdus littoralis sp. nov., whereas strain 12 is proposed as Xenorhabdus santafensis sp. nov. In this work, we present a dual insight into the biocidal potential and diversity of the Xenorhabdus genus, demonstrated by different numbers of putative insecticidal genes and biosynthetic gene clusters, along with a fresh exploration of the species within this genus.


Assuntos
Mariposas , Nematoides , Xenorhabdus , Animais , Xenorhabdus/genética , Filogenia , Argentina , Nematoides/genética , Mariposas/genética , Análise de Sequência , Simbiose
20.
New Phytol ; 241(6): 2340-2352, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38308116

RESUMO

We discuss which plant species are likely to become winners, that is achieve the highest global abundance, in changing landscapes, and whether plant-associated microbes play a determining role. Reduction and fragmentation of natural habitats in historic landscapes have led to the emergence of patchy, hybrid landscapes, and novel landscapes where anthropogenic ecosystems prevail. In patchy landscapes, species with broad niches are favoured. Plasticity in the degree of association with symbiotic microbes may contribute to broader plant niches and optimization of symbiosis costs and benefits, by downregulating symbiosis when it is unnecessary and upregulating it when it is beneficial. Plasticity can also be expressed as the switch from one type of mutualism to another, for example from nutritive to defensive mutualism with increasing soil fertility and the associated increase in parasite load. Upon dispersal, wide mutualistic partner receptivity is another facet of symbiont plasticity that becomes beneficial, because plants are not limited by the availability of specialist partners when arriving at new locations. Thus, under conditions of global change, symbiont plasticity allows plants to optimize the activity of mutualistic relationships, potentially allowing them to become winners by maximizing geographic occupancy and local abundance.


Assuntos
Ecossistema , Plantas , Simbiose/fisiologia , Solo
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