Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 147
Filtrar
Mais filtros

Tipo de documento
Intervalo de ano de publicação
1.
Appl Environ Microbiol ; 90(7): e0039424, 2024 07 24.
Artigo em Inglês | MEDLINE | ID: mdl-38916291

RESUMO

Microbial communities perform various functions, many of which contribute to ecosystem-level nutrient cycling via decomposition. Factors influencing leaf detrital decomposition are well understood in terrestrial and aquatic ecosystems, but much less is known about arthropod detrital inputs. Here, we sought to infer how differences in arthropod detritus affect microbial-driven decomposition and community function in a carnivorous pitcher plant, Sarracenia purpurea. Using sterile mesh bags filled with different types of sterile arthropod prey, we assessed if prey type influenced the rate of decomposition in pitcher plants over 7 weeks. Additionally, we measured microbial community composition and function, including hydrolytic enzyme activity and carbon substrate use. When comparing decomposition rates, we found that ant and beetle prey with higher exoskeleton content lost less mass compared with fly prey. We observed the highest protease activity in the fly treatment, which had the lowest exoskeleton content. Additionally, we saw differences in the pH of the pitcher fluid, driven by the ant treatment which had the lowest pH. According to our results from 16S rRNA gene metabarcoding, prey treatments with the highest bacterial amplicon sequence variant (ASV) richness (ant and beetle) were associated with prey that lost a lower proportion of mass over the 7 weeks. Overall, arthropod detritus provides unique nutrient sources to decomposer communities, with different prey influencing microbial hydrolytic enzyme activity and composition. IMPORTANCE: Microbial communities play pivotal roles in nutrient cycling via decomposition and nutrient transformation; however, it is often unclear how different substrates influence microbial activity and community composition. Our study highlights how different types of insects influence decomposition and, in turn, microbial composition and function. We use the aquatic pools found in a carnivorous pitcher plant as small, discrete ecosystems that we can manipulate and study independently. We find that some insect prey (flies) breaks down faster than others (beetles or ants) likely because flies contain more things that are easy for microbes to eat and derive essential nutrients from. This is also reflected in higher enzyme activity in the microbes decomposing the flies. Our work bridges a knowledge gap about how different substrates affect microbial decomposition, contributing to the broader understanding of ecosystem function in a nutrient cycling context.


Assuntos
Formigas , Microbiota , Sarraceniaceae , Animais , Sarraceniaceae/microbiologia , Sarraceniaceae/metabolismo , Formigas/microbiologia , Artrópodes , Bactérias/classificação , Bactérias/genética , Bactérias/metabolismo , Bactérias/isolamento & purificação , Besouros/microbiologia , RNA Ribossômico 16S/genética , Ecossistema , Cadeia Alimentar
2.
Am J Bot ; 110(10): e16230, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-37807697

RESUMO

PREMISE: The evolution of carnivorous pitcher traps across multiple angiosperm lineages represents a classic example of morphological convergence. Nevertheless, no comparative study to-date has examined pitcher evolution from a quantitative morphometric perspective. METHODS: In the present study, we used comparative morphometric approaches to quantify the shape space occupied by Heliamphora pitchers and to trace evolutionary trajectories through this space to examine patterns of divergence and convergence within the genus. We also investigated pitcher development, and, how the packing of pitchers is affected by crowding, a common condition in their natural environments. RESULTS: Our results showed that Heliamphora pitchers have diverged along three main axes in morphospace: (1) pitcher curvature; (2) nectar spoon elaboration; and (3) pitcher stoutness. Both curvature and stoutness are correlated with pitcher size, suggesting structural constraints in pitcher morphological evolution. Among the four traits (curvature, spoon elaboration, stoutness, and size), all but curvature lacked phylogenetic signal and showed marked convergence across the phylogeny. We also observed tighter packing of pitchers in crowded conditions, and this effect was most pronounced in curved, slender pitchers. CONCLUSIONS: Overall, our study demonstrates that diversification and convergent evolution of carnivory-related traits extends to finer evolutionary timescales, reinforcing the notion that ecological specialization may not necessarily be an evolutionary dead end.


Assuntos
Magnoliopsida , Sarraceniaceae , Filogenia , Áreas Alagadas , Carnivoridade , Magnoliopsida/genética , América do Sul
3.
Am Nat ; 200(5): 691-703, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-36260854

RESUMO

AbstractPredicting evolution in natural systems will require understanding how selection operates in multispecies communities. We predicted that the amount that traits evolve in multispecies mixtures would be less than the amount that would be predicted from the additive contributions of the pairwise interactions and that subordinate species will be more likely to evolve in competitive systems than dominant species. We conducted an experimental test of these predictions using a guild of protozoans found in the water-filled leaves of the pitcher plant Sarracenia purpurea. The response to selection did not significantly change as we increased richness from monocultures to two- and four-species mixtures. In accordance with our second prediction, subordinate species demonstrated greater growth in competition after selection than before, while dominant species generally showed no response to selection. Monod-type experiments to determine minimum resource levels found that the dominant species had much higher resource requirements than the subordinate species and that the minimum resource requirements evolved to be higher in the subordinate species. Importantly, these results suggest that subordinate species evolve to become more similar to dominant species, which may involve resource use convergence. Our findings and other recent works suggest that community diversity can affect evolution in surprising ways that warrant further investigation.


Assuntos
Sarraceniaceae , Folhas de Planta , Água , Fenótipo , Ecossistema
4.
Environ Microbiol ; 24(8): 3500-3516, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35384233

RESUMO

Plant-associated microbial communities can profoundly affect plant health and success, and research is still uncovering factors driving the assembly of these communities. Here, we examine how geography versus host species affects microbial community structure and differential abundances of individual taxa. We use metabarcoding to characterize the bacteria and eukaryotes associated with five, often co-occurring species of Sarracenia pitcher plants (Sarraceniaceae) and three natural hybrids along the longitudinal gradient of the U.S. Gulf Coast, as well as samples from S. purpurea in Massachusetts. To tease apart the effects of geography versus host species, we focus first on sites with co-occurring species and then on species located across different sites. Our analyses show that bacterial and eukaryotic community structures are clearly and consistently influenced by host species identity, with geographic factors also playing a role. Naturally occurring hybrids appear to also host unique communities, which are in some ways intermediate between their parent species. We see significant effects of geography (site and longitude), but these generally explain less of the variation among pitcher communities. Overall, in Sarracenia pitchers, host plant phenotype significantly affects the pitcher microbiomes and other associated organisms.


Assuntos
Microbiota , Sarraceniaceae , Bactérias/genética , Eucariotos , Geografia , Microbiota/genética , Sarraceniaceae/genética , Sarraceniaceae/microbiologia
5.
Ann Bot ; 129(3): 357-365, 2022 02 11.
Artigo em Inglês | MEDLINE | ID: mdl-34922341

RESUMO

BACKGROUND AND AIMS: The carnivorous pitcher plants of the genus Nepenthes have evolved modified leaves that act as pitcher traps. The traps are specialized for prey attraction, capture, digestion and nutrient uptake but not for photosynthetic assimilation. METHODS: In this study, we used antibodies against different photosynthetic (D1, Lhcb2, Lhcb4, RbcL) and respiratory-related (AOX, COXII) proteins for semi-quantification of these proteins in the assimilation part of the leaves and the pitcher traps of different Nepenthes species and hybrids. Different functional zones of the trap and the traps from different ontogenetic stages were investigated. The pitcher traps of the distantly related species Sarracenia purpurea ssp. venosa were used as an outgroup. In addition, chlorophyll fluorescence and infrared gas analysis were used for measurements of the net rate of photosynthesis (AN) and respiration in the dark (RD). KEY RESULTS: The pitcher traps contained the same or lower abundance of photosynthesis-related proteins in accordance with their low AN in comparison to the assimilation part of the leaves. Surprisingly, all traps contained a high amount of alternative oxidase (AOX) and low amount of cytochrome c oxidase subunit II (COX II) than in the assimilation part of the leaves. Thermal imaging did not confirm the role of AOX in pitcher thermogenesis. CONCLUSIONS: The pitcher traps contain a high amount of AOX enzyme. The possible role of AOX in specialized pitcher tissue is discussed based on knowledge of the role and function of AOX in non-carnivorous plants. The roles of AOX in prey attraction, balance between light and dark reactions of photosynthesis, homeostasis of reactive oxygen species, digestive physiology and nutrient assimilation are discussed.


Assuntos
Planta Carnívora , Sarraceniaceae , Proteínas Mitocondriais , Compostos Orgânicos , Oxirredutases , Proteínas de Plantas/metabolismo , Sarraceniaceae/metabolismo
6.
Am J Bot ; 109(12): 2006-2017, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36468545

RESUMO

PREMISE: Carnivorous plants are often associated with nutrient-poor soils and fires. Fire can decrease available soil nitrogen (N) and increase light availability, thus potentially favoring carnivory if prey provide N. Prey can also be a source of phosphorus (P), however, and soil P-availability often increases and competition for prey can decrease following fire. Carnivory thus might be more advantageous before fire when prey and/or soil P are more limiting. METHODS: We examined nutrient limitation of growth in a carnivorous plant, Sarracenia alata, in a wet pine savanna in southeastern Mississippi, USA. We measured growth and N:P tissue concentration responses of adult plants to a factorial arrangement of prey capture, neighbor reduction, and addition of N, P, and ash to the soil. We tested two hypotheses: (1) Prey provide N, and neighbor reduction and ash addition increase light and soil P and thus the benefit of carnivory; and (2) Prey provide P, neighbor reduction increases prey and/or P, and prey exclusion reduces growth the most when neighbors are not reduced. RESULTS: The exclusion of prey reduced growth more when neighbors were not reduced, an effect that was ameliorated slightly by the addition of P to the soil (the P-limitation hypothesis). Prey exclusion caused a decrease in tissue P when N was added to the soil. CONCLUSIONS: The results of this study with adult plants differed from those of a previous study using small juvenile plants, suggesting a shift from light limitation to P and prey limitation with increasing size.


Assuntos
Sarraceniaceae , Fósforo , Nitrogênio/análise , Carnivoridade , Nutrientes , Solo , Plantas
7.
J Biol Phys ; 48(1): 55-78, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-35089468

RESUMO

The original computers were people using algorithms to get mathematical results such as rocket trajectories. After the invention of the digital computer, brains have been widely understood through analogies with computers and now artificial neural networks, which have strengths and drawbacks. We define and examine a new kind of computation better adapted to biological systems, called biological computation, a natural adaptation of mechanistic physical computation. Nervous systems are of course biological computers, and we focus on some edge cases of biological computing, hearts and flytraps. The heart has about the computing power of a slug, and much of its computing happens outside of its forty thousand neurons. The flytrap has about the computing power of a lobster ganglion. This account advances fundamental debates in neuroscience by illustrating ways that classical computability theory can miss complexities of biology. By this reframing of computation, we make way for resolving the disconnect between human and machine learning.


Assuntos
Sarraceniaceae , Algoritmos , Computadores , Humanos , Redes Neurais de Computação , Neurônios/fisiologia
8.
Int J Mol Sci ; 23(17)2022 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-36077275

RESUMO

Carnivorous plants have fascinated researchers and hobbyists for centuries because of their mode of nutrition which is unlike that of other plants. They are able to produce bioactive compounds used to attract, capture and digest prey but also as a defense mechanism against microorganisms and free radicals. The main purpose of this review is to provide an overview of the secondary metabolites with significant biological activity found in the Sarraceniaceae family. The review also underlines the necessity of future studies for the biochemical characterization of the less investigated species. Darlingtonia, Heliamphora and Sarracenia plants are rich in compounds with potential pharmaceutical and medical uses. These belong to several classes such as flavonoids, with flavonol glycosides being the most abundant, monoterpenes, triterpenes, sesquiterpenes, fatty acids, alkaloids and others. Some of them are well characterized in terms of chemical properties and biological activity and have widespread commercial applications. The review also discusses biological activity of whole extracts and commercially available products derived from Sarraceniaceae plants. In conclusion, this review underscores that Sarraceniaceae species contain numerous substances with the potential to advance health. Future perspectives should focus on the discovery of new molecules and increasing the production of known compounds using biotechnological methods.


Assuntos
Alcaloides , Sarraceniaceae , Alcaloides/metabolismo , Plantas , Sarraceniaceae/metabolismo
9.
Ecol Lett ; 24(1): 94-101, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33079483

RESUMO

Incremental increases in a driver variable, such as nutrients or detritus, can trigger abrupt shifts in aquatic ecosystems that may exhibit hysteretic dynamics and a slow return to the initial state. A model system for understanding these dynamics is the microbial assemblage that inhabits the cup-shaped leaves of the pitcher plant Sarracenia purpurea. With enrichment of organic matter, this system flips within three days from an oxygen-rich state to an oxygen-poor state. In a replicated greenhouse experiment, we enriched pitcher-plant leaves at different rates with bovine serum albumin (BSA), a molecular substitute for detritus. Changes in dissolved oxygen (DO) and undigested BSA concentration were monitored during enrichment and recovery phases. With increasing enrichment rates, the dynamics ranged from clockwise hysteresis (low), to environmental tracking (medium), to novel counter-clockwise hysteresis (high). These experiments demonstrate that detrital enrichment rate can modulate a diversity of hysteretic responses within a single aquatic ecosystem, and suggest different management strategies may be needed to mitigate the effects of high vs. low rates of detrital enrichment.


Assuntos
Ecossistema , Sarraceniaceae , Modelos Biológicos , Folhas de Planta
10.
Mol Phylogenet Evol ; 154: 106961, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-32956799

RESUMO

Heliamphora is a genus of carnivorous pitcher plants endemic to the Guiana Highlands with fragmented distributions. We present a well resolved, time-calibrated, and comprehensive Heliamphora phylogeny estimated using Bayesian inference and maximum likelihood based on nuclear genes (26S, ITS, and PHYC) and secondary calibration. We used stochastic mapping to infer ancestral states of morphological characters and ecological traits. Our ancestral state estimations revealed that the pitcher drainage structures characteristic of the genus transformed from a hole to a slit in single clade, while other features (scape pubescence and hammock-like growth) have been gained and lost multiple times. Habitat was similarly labile in Heliamphora, with multiple transitions from the ancestral highland habitats into the lowlands. Using a Mantel test, we found closely related species tend to be geographically closely distributed. Placing our phylogeny in a historical context, major clades likely emerged through both vicariance and dispersal during the Miocene with more recent diversification driven by vertical displacement during the Pleistocene glacial-interglacial thermal oscillations. Despite the dynamic climatic history experienced by Heliamphora, the temperature changes brought by global warming pose a significant threat, particularly for those species at the highest elevations.


Assuntos
Filogenia , Filogeografia , Sarraceniaceae/classificação , Áreas Alagadas , Teorema de Bayes , Funções Verossimilhança , Modelos Biológicos , Nucleotídeos/genética , Fenótipo , América do Sul
11.
Physiol Plant ; 173(3): 1221-1229, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34346074

RESUMO

Suberin, as a lipid polyester barrier, limits the movement of gas, water, and solutes, and plays important roles in plant protection and growth. In this study, a CDS encoding glycerol-3-phosphate acyltransferase 5 (GPAT5) was cloned from Sarracenia purpurea to investigate the gene function. SpGPAT5 shares 72% identity and 80% similarity to AtGPAT5 that is required for suberin synthesis. Fluorol Yellow 088 staining showed that the S. purpurea pitcher (specific leaf) tube contained more suberin in the adaxial surface compared to the lid, and SpGPAT5 transcripts were detected in the pitcher. Previous reported Atgpat5-1 phenotypes were complemented with SpGPAT5 showing that the Atgpat5-1 seed coat had increased permeability of tetrazolium red and the mutant was sensitive to salt. We also found that SpGPAT5 was able to revert the hyperhydric phenotype of Atgpat5-1 under high humidity. Thus, this study suggests that SpGPAT5 can functionally replace AtGPAT5 and contributes to plant tolerance to high humidity, which maybe assist in understanding the role of suberin-associated waxes in S. purpurea pitchers for water retention.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Sarraceniaceae , 1-Acilglicerol-3-Fosfato O-Aciltransferase , Aciltransferases/genética , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Glicerol , Umidade , Fosfatos
12.
Molecules ; 26(9)2021 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-33919120

RESUMO

Rare carnivorous plants representing the genus Sarracenia are perceived as very interesting to scientists involved in various fields of botany, ethnobotany, entomology, phytochemistry and others. Such high interest is caused mainly by the unique capacity of Sarracenia spp. to attract insects. Therefore, an attempt to develop a protocol for micropropagation of the Sarracenia alata (Alph.Wood) Alph.Wood, commonly named yellow trumpets, and to identify the specific chemical composition of volatile compounds of this plant in vitro and ex vivo was undertaken. Thus, the chemical volatile compounds excreted by the studied plant to attract insects were recognized with the application of the headspace solid-phase microextraction (HS-SPME) coupled with the GC-MS technique. As the major volatile compounds (Z)-3-hexen-1-ol (16.48% ± 0.31), (E)-3-hexen-1-ol acetate (19.99% ± 0.01) and ß-caryophyllene (11.30% ± 0.27) were identified. Further, both the chemical assumed to be responsible for attracting insects, i.e., pyridine (3.10% ± 0.07), and whole plants were used in in vivo bioassays with two insect species, namely Drosophila hydei and Acyrthosiphon pisum. The obtained results bring a new perspective on the possibilities of cultivating rare carnivorous plants in vitro since they are regarded as a valuable source of bioactive volatile compounds, as including ones with repellent or attractant activity.


Assuntos
Interações Hospedeiro-Parasita , Insetos , Sarraceniaceae/química , Sarraceniaceae/parasitologia , Compostos Orgânicos Voláteis/análise , Compostos Orgânicos Voláteis/química , Madeira/química , Animais , Bioensaio , Carga Parasitária , Desenvolvimento Vegetal , Brotos de Planta/química , Brotos de Planta/parasitologia
13.
Anal Chem ; 92(16): 11018-11028, 2020 08 18.
Artigo em Inglês | MEDLINE | ID: mdl-32658454

RESUMO

Hydrogen/Deuterium Exchange (HDX) coupled with Mass Spectrometry (HDX-MS) is a sensitive and robust method to probe protein conformational changes and protein-ligand interactions. HDX-MS relies on successful proteolytic digestion of target proteins under acidic conditions to localize perturbations in exchange behavior to protein structure. The ability of the protease to produce small peptides and overlapping fragments and provide sufficient coverage of the protein sequence is essential for localizing regions of interest. While the acid protease pepsin has been the enzyme of choice for HDX-MS studies, recently, it was shown that aspartic proteases from carnivorous pitcher plants of the genus Nepenthes are active under low-pH conditions and cleave at basic residues that are "forbidden" in peptic digests. In this report, we describe the utility of one of these enzymes, Nepenthesin II (NepII), in a HDX-MS workflow. A systematic and statistical analysis of data from 11 proteins (6391 amino acid residues) digested with immobilized porcine pepsin or NepII under conditions compatible with HDX-MS was performed to examine protease cleavage specificities. The cleavage of pepsin was most influenced by the amino acid residue at position P1. Phe, Leu, and Met are favored residues, each with a cleavage probability of greater than 40%. His, Lys, Arg, or Pro residues prohibit cleavage when found at the P1 position. In contrast, NepII offers advantageous cleavage to all basic residues and produces shortened peptides that could improve the spatial resolution in HDX-MS studies.


Assuntos
Enzimas Imobilizadas/química , Pepsina A/química , Proteólise , Animais , Biocatálise , Deutério/química , Medição da Troca de Deutério , Espectrometria de Massas , Sarraceniaceae/enzimologia , Especificidade por Substrato , Suínos
14.
Am J Bot ; 107(11): 1606-1613, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-33145765

RESUMO

PREMISE: The association of carnivory (an adaptation to nutrient-poor soils) with fire has been described as a paradox, given increases in nutrient availability that often accompany fire. The nutrients that increase in availability following fire, however, may not be the same as those provided by prey and may not reduce nutrient limitation if accompanied by even greater increases in light. METHODS: Using a factorial experiment in the field, we examined how simulated fire (clipping plus nitrogen-free fertilizer addition) and prey-derived nutrient availability (prey exclusion) interacted to influence carnivorous potential in Sarracenia alata and belowground competition with its neighbors (manipulated via trenching). We hypothesized that simulated fire combined with prey exclusion would (1) increase the potential for prey capture relative to shade avoidance, hereafter, relative prey-capture potential (RPCP), and/or (2) increase belowground competition with neighboring plants. RESULTS: Sarracenia alata increased RPCP in response to the combination of simulated fire and prey exclusion, despite increases in phosphorus and other nutrients associated with the simulated fire treatment, suggesting that prey capture potential increases in response to increased nitrogen limitation resulting from increases in light and/or phosphorus after fire. We found no evidence of belowground competition. CONCLUSIONS: The potential importance of carnivory in Sarracenia alata increases following fire. This result helps to explain the paradoxical association of carnivorous plants with fire by demonstrating the potential for prey-derived nutrient limitation to increase rather than decrease in response to increases in light and nutrients other than nitrogen following fire.


Assuntos
Incêndios , Sarraceniaceae , Carnivoridade , Nitrogênio , Fósforo
15.
Yale J Biol Med ; 93(2): 277-281, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32607088

RESUMO

Oral herpes labialis, more commonly known as cold sores, are a common encountered viral infection involving herpes simplex virus-1 (HSV-1). Although relatively benign, these lesions can be both unsightly and clinically difficult to manage. Prescription standards of care and over-the-counter agents, such as docosonal, have often shown only limited efficacy in both decreasing lesional pain and reducing duration of lesional symptomology and are not without potential side effects. Despite some success with acute remediation, recurrent episodes often occur, with seemingly no imparted protection or suppression against future outbreaks. This case report involves the successful treatment of oro-facial herpes labialis with a synergistic botanical blend with marked reduction in symptoms, pain score, and lesion duration. Monitoring and evaluation post-treatment and application during future prodromal symptoms was also performed demonstrating additional reduction in the frequency of subsequent outbreaks. This case report supports the use of this treatment for prodromal and acute treatment of oro-facial herpes infection and appears to impart a reduction in the frequency of future outbreaks.


Assuntos
Eleutherococcus , Glycyrrhiza , Herpes Labial , Hypericum , Lavandula , Melissa , Sarraceniaceae , Cicatrização/efeitos dos fármacos , Adulto , Analgésicos/farmacologia , Anti-Inflamatórios/farmacologia , Antivirais/farmacologia , Composição de Medicamentos , Feminino , Géis/farmacologia , Herpes Labial/diagnóstico , Herpes Labial/fisiopatologia , Herpes Labial/terapia , Humanos , Prevenção Secundária/métodos , Simplexvirus/efeitos dos fármacos , Resultado do Tratamento
16.
Am Nat ; 193(2): 227-239, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30720361

RESUMO

Gaining knowledge of how ecosystems provide essential services to humans is of primary importance, especially with the current threat of climate change. Yet little is known about how increased temperature will impact the biodiversity-ecosystem functioning (BEF) relationship. We tackled this subject theoretically and experimentally. We developed a BEF theory based on mechanistic population dynamic models, which allows the inclusion of the effect of temperature. Using experimentally established relationships between attack rate and temperature, the model predicts that temperature increase will intensify competition, and consequently the BEF relationship will flatten or even become negative. We conducted a laboratory experiment with natural microbial microcosms, and the results were in agreement with the model predictions. The experimental results also revealed that an increase in both temperature average and variation had a more intense effect than an increase in temperature average alone. Our results indicate that under climate change, high diversity may not guarantee high ecosystem functioning.


Assuntos
Mudança Climática , Ecossistema , Modelos Biológicos , Sarraceniaceae , Temperatura
17.
Appl Environ Microbiol ; 85(6)2019 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-30635382

RESUMO

A large number of descriptive surveys have shown that microbial communities experience successional changes over time and that ecological dominance is common in the microbial world. However, direct evidence for the ecological processes mediating succession or causing ecological dominance remains rare. Different dispersal abilities among species may be a key mechanism. We surveyed fungal diversity within a metacommunity of pitchers of the model carnivorous plant Sarracenia purpurea and discovered that the yeast Candida pseudoglaebosa was ecologically dominant. Its frequency in the metacommunity increased during the growing season, and it was not replaced by other taxa. We next measured its competitive ability in a manipulative laboratory experiment and tracked its dispersal over time in nature. Despite its dominance, C. pseudoglaebosa is not a superior competitor. Instead, it is a superior disperser: it arrives in pitchers earlier, and disperses into more pitchers, than other fungi. Differential dispersal across the spatially structured metacommunity of individual pitchers emerges as a key driver of the continuous dominance of C. pseudoglaebosa during succession.IMPORTANCE Microbial communities are ubiquitous and occupy nearly every imaginable habitat and resource, including human-influenced habitats (e.g., fermenting food and hospital surfaces) and habitats with little human influence (e.g., aquatic communities living in carnivorous plant pitchers). We studied yeast communities living in pitchers of the carnivorous purple pitcher plant to understand how and why microbial communities change over time. We found that dispersal ability is not only important for fungal communities early in their existence, it can also determine which species is dominant (here, the yeast Candida pseudoglaebosa) long after the species and its competitors have arrived. These results contrast with observations from many human-influenced habitats, in which a good competitor eventually outcompetes good dispersers, since humans often design these habitats to favor a specific competitor. This study will help microbiologists understand the qualities of microbial species that enable takeover of new habitats in both natural and human-influenced environments.


Assuntos
Fungos/crescimento & desenvolvimento , Microbiota , Sarraceniaceae/microbiologia , Ecossistema , Fungos/classificação , Fungos/genética , Fungos/isolamento & purificação
18.
Mol Ecol ; 28(2): 281-292, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30106192

RESUMO

Resource variation along abiotic gradients influences subsequent trophic interactions and these effects can be transmitted through entire food webs. Interactions along abiotic gradients can provide clues as to how organisms will face changing environmental conditions, such as future range shifts. However, it is challenging to find replicated systems to study these effects. Phytotelmata, such as those found in carnivorous plants, are isolated aquatic communities and thus form a good model for the study of replicated food webs. Due to the degraded nature of the prey, molecular techniques provide a useful tool to study these communities. We studied the pitcher plant Sarracenia purpurea L. in allochthonous populations along an elevational gradient in the Alps and Jura. We predicted that invertebrate richness in the contents of the pitcher plants would decrease with increasing elevation, reflecting harsher environmental conditions. Using metabarcoding of the COI gene, we sequenced the invertebrate contents of these pitcher plants. We assigned Molecular Operational Taxonomic Units at ordinal level as well as recovering species-level data. We found small but significant changes in community composition with elevation. These recovered sequences could belong to invertebrate prey, rotifer inquilines, pollinators and other animals possibly living inside the pitchers. However, we found no directional trend or site-based differences in MOTU richness with elevational gradient. Use of molecular techniques for dietary or contents analysis is a powerful way to examine numerous degraded samples, although factors such as DNA persistence and the relationship with species presence still have to be completely determined.


Assuntos
Carnívoros/genética , Código de Barras de DNA Taxonômico , Fenômenos Fisiológicos Vegetais/genética , Sarraceniaceae/fisiologia , Altitude , Animais , Biodiversidade , Carnívoros/fisiologia , DNA/genética , DNA/isolamento & purificação , Ecossistema , Cadeia Alimentar , Plantas/genética , Sarraceniaceae/genética
19.
J Exp Bot ; 70(13): 3379-3389, 2019 07 05.
Artigo em Inglês | MEDLINE | ID: mdl-31120525

RESUMO

The lipid-derived jasmonate phytohormones (JAs) regulate a wide spectrum of physiological processes in plants such as growth, development, tolerance to abiotic stresses, and defence against pathogen infection and insect attack. Recently, a new role for JAs has been revealed in carnivorous plants. In these specialized plants, JAs can induce the formation of digestive cavities and regulate enzyme production in response to different stimuli from caught prey. Appearing to be a new function for JAs in plants, a closer look reveals that the signalling pathways involved resemble known signalling pathways from plant defence mechanisms. Moreover, the digestion-related secretome of carnivorous plants is composed of many pathogenesis-related (PR) proteins and low molecular weight compounds, indicating that the plant carnivory syndrome is related to and has evolved from plant defence mechanisms. This review describes the similarities between defence and carnivory. It further describes how, after recognition of caught insects, JAs enable the carnivorous plants to digest and benefit from the prey. In addition, a causal connection between electrical and jasmonate signalling is discussed.


Assuntos
Ciclopentanos/metabolismo , Drosera/metabolismo , Oxilipinas/metabolismo , Reguladores de Crescimento de Plantas/metabolismo , Sarraceniaceae/metabolismo , Ciclopentanos/imunologia , Oxilipinas/imunologia , Imunidade Vegetal , Metabolismo Secundário , Transdução de Sinais , Viridiplantae/metabolismo
20.
Artigo em Inglês | MEDLINE | ID: mdl-30868226

RESUMO

In specialized pollination systems, floral scents are crucial for flower-pollinator communication, but key volatiles that attract pollinators are unknown for most systems. Deceptive Ceropegia trap flowers are famous for their elaborate mechanisms to trap flies. Recent studies revealed species-specific floral chemistry suggesting highly specialized mimicry strategies. However, volatiles involved in fly attraction were until now identified in C. dolichophylla and C. sandersonii, only. We here present data on C. stenantha for which flower scent and pollinators were recently described, but volatiles involved in flower-fly communication stayed unknown. We performed electrophysiological measurements with scatopsid fly pollinators (Coboldia fuscipes) and identified 12 out of 13 biologically active floral components. Among these volatiles some were never described from any organism but C. stenantha. We synthesized these components, tested them on antennae of male and female flies, and confirmed their biological activity. Overall, our data show that half of the volatiles emitted from C. stenantha flowers are perceived by male and female fly pollinators and are potentially important for flower-fly communication in this pollination system. Further studies are needed to clarify the role of the electrophysiologically active components in the life of scatopsid fly pollinators, and to fully understand the pollination strategy of C. stenantha.


Assuntos
Dípteros , Flores/química , Polinização , Sarraceniaceae/química , Animais , Comportamento Animal , Feminino , Masculino , Odorantes , Compostos Orgânicos Voláteis/química
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA