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Duelos de caçador: predação e familialização na Amazônia indígena / Hunter\'s Duel: predation and familiarization in the indigenous AmazonPansica, Rafael Rocha 14 October 2016 (has links)
Por um cunho bibliográfico, esta tese se debruça sobre as caçadas de certas etnografias da Amazônia indígena buscando compreender as relações, aí estabelecidas, entre as perspectivas da predação e da familiarização. Trata-se de um ensaio comparativo, inspirado no método lévi-straussiano da análise dos mitos, que justapõe para o cotejo e a análise as etnografias [1] da caça yudjá aos porcos, [2] da caça coletiva dos Arara, [3] dos mitos yaminawa sobre os encontros cinegéticos e [4] da caça awá-guajá aos guaribas. A análise comparativa das etnografias sustentará, nas considerações finais deste texto, uma proposta nova para o entendimento dos conceitos de predação e familiarização. / From a bibliographic imprint, the present dissertation bend on the hunting of certain ethnographies from the indigenous Amazonia, seeking for understanding the relationships, there establish, between the perspectives of predation and familiarization. This is a comparative essay, inspired by Lévi-Straussian method for the analysis, which juxtaposes for collation and review the ethnographies [1] of Yudjá hunting to pigs, [2] the collective hunting of the Arara people, [3] the Yaminawa\'s myths of hunting and [4] the Awá-Guajá hunting to howler monkeys. At the ultimate remarks of this manuscript, the comparative analysis of the ethnografies will sustain a different proposal to comprehend the concepts of predation and familiarization.
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Does an evolutionary change in the water sowbug Asellus aquaticus L. alter its functional role?Choudhury, Md. Maidul Islam January 2011 (has links)
The ecology behind evolutionary diversification is a well studied area of research, whereas the effects of evolution on ecosystems get little attention. In line with ecological theory, evolutionary diversification of a species could influence different ecosystem aspects such as food web composition, energy flow, nutrient cycling etc. The main objective of this study was to investigate whether two diverging ecotypes (reed and chara) of Asellus aquaticus differ regarding their role in two aquatic ecosystem processes: decomposition of terrestrial leaves and grazing of periphyton. Their role in ecosystem process as well as treatment effects on fitness, measured as growth and survival, were investigated in a laboratory experiment with various levels of intra-specific competition and inter-specific interactions with the amphipod Gammarus pulex. The isopods were collected from two Swedish lakes: Lake Tåkern and Lake Fardume. These two lakes represent different history of ecotype divergence. The experimental design consisted of 2-L aquaria, each providing elm leaves (Ulmus glabra), oak leaves (Quercus roburleaves) and periphyton as food sources. Ten treatments with five replicates were applied for each lake and the experiment lasted for four weeks. The study showed that there was no significant difference between chara and reed ecotype in their functional role. However, the rate of ecosystem processes per individual decreased in competitive interactions. In high density, decomposition per dry weight consumer was low and total algae biomass was high at the end of four weeks due to intra-specific competition. Moreover, ecosystem processes were lowest in inter-specific competition between Gammarus pulex and each ecotype. Present study also shows that ecotypes from the different lakes, having different history, had different responses to mortality and growth.
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Duelos de caçador: predação e familialização na Amazônia indígena / Hunter\'s Duel: predation and familiarization in the indigenous AmazonRafael Rocha Pansica 14 October 2016 (has links)
Por um cunho bibliográfico, esta tese se debruça sobre as caçadas de certas etnografias da Amazônia indígena buscando compreender as relações, aí estabelecidas, entre as perspectivas da predação e da familiarização. Trata-se de um ensaio comparativo, inspirado no método lévi-straussiano da análise dos mitos, que justapõe para o cotejo e a análise as etnografias [1] da caça yudjá aos porcos, [2] da caça coletiva dos Arara, [3] dos mitos yaminawa sobre os encontros cinegéticos e [4] da caça awá-guajá aos guaribas. A análise comparativa das etnografias sustentará, nas considerações finais deste texto, uma proposta nova para o entendimento dos conceitos de predação e familiarização. / From a bibliographic imprint, the present dissertation bend on the hunting of certain ethnographies from the indigenous Amazonia, seeking for understanding the relationships, there establish, between the perspectives of predation and familiarization. This is a comparative essay, inspired by Lévi-Straussian method for the analysis, which juxtaposes for collation and review the ethnographies [1] of Yudjá hunting to pigs, [2] the collective hunting of the Arara people, [3] the Yaminawa\'s myths of hunting and [4] the Awá-Guajá hunting to howler monkeys. At the ultimate remarks of this manuscript, the comparative analysis of the ethnografies will sustain a different proposal to comprehend the concepts of predation and familiarization.
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Genetic and environmental influences on the germination of basidiospores in the Cryptococcus neoformans species complexForsythe, Adrian January 2016 (has links)
In basidiomycetous fungi, the viability of gametes is an important component of sexual
fitness and can have implications for speciation events. Prior estimates of basidiospore
germination are highly variable and the occurrence of reproduction between these lineages
suggests that reproductive isolation is incomplete. Genetic incompatibilities during
meiosis have been attributed to much of the offspring inviability. However, the influence
of environmental factors on basidiospore germination in Cryptococcus are not well
known. In this study, we used human opportunistic yeast pathogens, Cryptococcus neoformans
and Cryptococcus deneoformans, as models to investigate the potential effects
of selected genetic and environmental factors on basidiospore germination. We evaluated
basidiospore germination of six genetic crosses by pairing a total of five strains,
three intraspecific crosses and three interspecific crosses, between C. neoformans and
C. deneoformans. The offspring of genetic crosses were incubated under multiple media
and temperature treatments and scored for their germination ability. In general, spores
from intraspecific crosses had greater germination potential than those from interspecific
crosses. Growth under high temperatures was the most significant influence on basidiospore
germination on these crosses. Furthermore, there were notable interaction effects
between environmental factors and parental strains or strain pairs on basidiospore
germination. The interaction between the sex-specific genes and environmental pressures
impact reproductive barriers and blur species distinctions within the Cryptococcus
neoformans species complex. And so, reduced viability of hybrid offspring can have implications for Cryptococcus speciation, ecology, and pathogenesis as hybridization events
are an effective method of increasing pathogenicity, expanding species distributions and
increasing tolerance to novel environments or hosts. / Thesis / Master of Science (MSc) / In basidiomycetous fungi, the viability of gametes is an important component of sexual
fitness and can have implications for speciation events. The Cryptococcus neoformans
species complex are a group of opportunistic pathogens, for which hybridization can
be facilitated readily under laboratory conditions, creating offspring that are generally
completely inviable or have low germination potential. Antagonistic genetic interactions
are mostly responsible for offspring inviability, yet the impacts of environmental factors
is not known. Multiple genetic crosses between Cryptococcus strains were used as
a model to investigate species relationships by examining the impacts of genetic and
environmental factors on offspring germination potential.
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Non-random inter-specific encounters between Amazon understory forest birds : what are theyand how do they change / Encontra interespecífica não aleatória entre aves de sub-bosque amazônico: qual elas são e como elas mudam?Poitevin, Caroline Myriam January 2016 (has links)
Os bandos mistos de aves são agregações sociais complexas estáveis durante o tempo e espaço. Até hoje, a estrutura social dessas espécies foi descrita a partir de estudos subjetivos de campo ou a partir de compilações do número e intensidade das interações a nível de todo o grupo, sem considerar as interações par-a-par individualmente. Nossos objetivos foram buscar evidências de associações não-randômicas entre pares de espécies de aves, delimitar os grupos a partir das espécies com as associações mais fortes e verificar se há diferenças na estrutura social entre os habitat de floresta primária e secundária. Utilizamos dados de ocorrência das espécies coletados a partir de redes de neblina e gravação de vocalizações para identificar pares de espécies que foram co-detectadas mais frequentemente do que o esperado a partir do modelo nulo e compararamos a força dessa interação entre as florestas tropicais primária e secundária Amazônicas. Nós também utilizamos as associações par-a-par para construir as redes de interação social e suas mudanças entre os tipos de habitat. Nós encontramos muitas interações positivas fortes entre as espécies, mas nenhuma evidência de repulsão. As análises das redes de interação revelaram vários grupos de espécies que corroboram com grupos ecológios descritos na literatura. Além disso, tanto a estrutura da rede de interação como a força da interação se alteraram drasticamente com a perturbação do habitat, com formação de algumas associações novas, mas uma tendência geral para quebra de associações entre as espécies. Nossos resultados mostram que as interações sociais entre essas aves podem ser fortemente afetados pela degradação do habitat, sugerindo que a estabilidade das interações desenvolvida entre espécies é ameaçada pelos distúrbios causados pelo homem. / Inter-specific associations of birds are complex social phenomena, frequently detected and often stable over time and space. So far, the social structure of these associations has been largely deduced from subjective assessments in the field or by counting the number of inter-specific encounters at the whole-group level, without considering changes to individual pairwise interactions. Here, we look for evidence of non-random association between pairs of bird species, delimit groups of more strongly associated species and examine differences in social structure between old growth and secondary forest habitat. We used records of bird species detection from mist-netting capture and from acoustic recordings to identify pairwise associations that were detected more frequently than expected under a null distribution, and compared the strength of these associations between old-growth and secondary forest Amazonian tropical forest. We also used the pairwise strength associations to visualize the social network structure and its changes between habitat types. We found many strongly positive interactions between species, but no evidence of repulsion. Network analyses revealed several modules of species that broadly agree with the subjective groupings described in the ornithological literature. Furthermore, both network structure and association strength changed drastically with habitat disturbance, with the formation of a few new associations but a general trend towards the breaking of associations between species. Our results show that social grouping in birds is real and may be strongly affected by habitat degradation, suggesting that the stability of the associations is threatened by anthropogenic disturbance.
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Reciproční predace mezi nepůvodními raky a lososovitými rybami Kdo koho žere? / Reciprocal predation between non-native crayfish and salmonids Who eats whom?MÜLLEROVÁ, Lucie January 2017 (has links)
Signal crayfish (Pacifastacus leniusculus) is important invasive species in European freshwaters. Its influence on other freshwater organisms is well known from the literature, as well as direct and indirect impact on fish assemblages. This work was focused on the experimental evaluation of non-indigenous signal crayfish as a predator of salmonids compared to indigenous noble crayfish (Astacus astacus). Moreover, the possible importance of young-of-the-year signal crayfish as a prey for salmonids was assessed. There were carried out experiments using eggs and hatchings of grayling (Thymallus thymallus) as a prey for adult and subadult specimens of both, signal and noble crayfish. Next experiment used young-of-the-year signal crayfish as a prey for young-of-the-year of brown trout (Salmo trutta). Results showed that the danger of signal crayfish for grayling eggs is slightly higher. However, detected differences were surprisingly lower and in the majority of parameters even insignificant. In the case of grayling hatchings, was not detected any significant difference at all. The abilities of both tested species to prey on eggs and hatchings are therefore very similar, comparable. Even so, the effect of signal crayfish can be importantly higher in natural conditions because of its more dense populations, higher growth rate and fast maturation. In accordance to our findings, it is evident that brown trout has no so high effect of crayfish juveniles compared with crayfish effect on salmonids early developmental stages. Crayfish are therefore more likely able to limit salmonids than conversely.
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Non-random inter-specific encounters between Amazon understory forest birds : what are theyand how do they change / Encontra interespecífica não aleatória entre aves de sub-bosque amazônico: qual elas são e como elas mudam?Poitevin, Caroline Myriam January 2016 (has links)
Os bandos mistos de aves são agregações sociais complexas estáveis durante o tempo e espaço. Até hoje, a estrutura social dessas espécies foi descrita a partir de estudos subjetivos de campo ou a partir de compilações do número e intensidade das interações a nível de todo o grupo, sem considerar as interações par-a-par individualmente. Nossos objetivos foram buscar evidências de associações não-randômicas entre pares de espécies de aves, delimitar os grupos a partir das espécies com as associações mais fortes e verificar se há diferenças na estrutura social entre os habitat de floresta primária e secundária. Utilizamos dados de ocorrência das espécies coletados a partir de redes de neblina e gravação de vocalizações para identificar pares de espécies que foram co-detectadas mais frequentemente do que o esperado a partir do modelo nulo e compararamos a força dessa interação entre as florestas tropicais primária e secundária Amazônicas. Nós também utilizamos as associações par-a-par para construir as redes de interação social e suas mudanças entre os tipos de habitat. Nós encontramos muitas interações positivas fortes entre as espécies, mas nenhuma evidência de repulsão. As análises das redes de interação revelaram vários grupos de espécies que corroboram com grupos ecológios descritos na literatura. Além disso, tanto a estrutura da rede de interação como a força da interação se alteraram drasticamente com a perturbação do habitat, com formação de algumas associações novas, mas uma tendência geral para quebra de associações entre as espécies. Nossos resultados mostram que as interações sociais entre essas aves podem ser fortemente afetados pela degradação do habitat, sugerindo que a estabilidade das interações desenvolvida entre espécies é ameaçada pelos distúrbios causados pelo homem. / Inter-specific associations of birds are complex social phenomena, frequently detected and often stable over time and space. So far, the social structure of these associations has been largely deduced from subjective assessments in the field or by counting the number of inter-specific encounters at the whole-group level, without considering changes to individual pairwise interactions. Here, we look for evidence of non-random association between pairs of bird species, delimit groups of more strongly associated species and examine differences in social structure between old growth and secondary forest habitat. We used records of bird species detection from mist-netting capture and from acoustic recordings to identify pairwise associations that were detected more frequently than expected under a null distribution, and compared the strength of these associations between old-growth and secondary forest Amazonian tropical forest. We also used the pairwise strength associations to visualize the social network structure and its changes between habitat types. We found many strongly positive interactions between species, but no evidence of repulsion. Network analyses revealed several modules of species that broadly agree with the subjective groupings described in the ornithological literature. Furthermore, both network structure and association strength changed drastically with habitat disturbance, with the formation of a few new associations but a general trend towards the breaking of associations between species. Our results show that social grouping in birds is real and may be strongly affected by habitat degradation, suggesting that the stability of the associations is threatened by anthropogenic disturbance.
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Non-random inter-specific encounters between Amazon understory forest birds : what are theyand how do they change / Encontra interespecífica não aleatória entre aves de sub-bosque amazônico: qual elas são e como elas mudam?Poitevin, Caroline Myriam January 2016 (has links)
Os bandos mistos de aves são agregações sociais complexas estáveis durante o tempo e espaço. Até hoje, a estrutura social dessas espécies foi descrita a partir de estudos subjetivos de campo ou a partir de compilações do número e intensidade das interações a nível de todo o grupo, sem considerar as interações par-a-par individualmente. Nossos objetivos foram buscar evidências de associações não-randômicas entre pares de espécies de aves, delimitar os grupos a partir das espécies com as associações mais fortes e verificar se há diferenças na estrutura social entre os habitat de floresta primária e secundária. Utilizamos dados de ocorrência das espécies coletados a partir de redes de neblina e gravação de vocalizações para identificar pares de espécies que foram co-detectadas mais frequentemente do que o esperado a partir do modelo nulo e compararamos a força dessa interação entre as florestas tropicais primária e secundária Amazônicas. Nós também utilizamos as associações par-a-par para construir as redes de interação social e suas mudanças entre os tipos de habitat. Nós encontramos muitas interações positivas fortes entre as espécies, mas nenhuma evidência de repulsão. As análises das redes de interação revelaram vários grupos de espécies que corroboram com grupos ecológios descritos na literatura. Além disso, tanto a estrutura da rede de interação como a força da interação se alteraram drasticamente com a perturbação do habitat, com formação de algumas associações novas, mas uma tendência geral para quebra de associações entre as espécies. Nossos resultados mostram que as interações sociais entre essas aves podem ser fortemente afetados pela degradação do habitat, sugerindo que a estabilidade das interações desenvolvida entre espécies é ameaçada pelos distúrbios causados pelo homem. / Inter-specific associations of birds are complex social phenomena, frequently detected and often stable over time and space. So far, the social structure of these associations has been largely deduced from subjective assessments in the field or by counting the number of inter-specific encounters at the whole-group level, without considering changes to individual pairwise interactions. Here, we look for evidence of non-random association between pairs of bird species, delimit groups of more strongly associated species and examine differences in social structure between old growth and secondary forest habitat. We used records of bird species detection from mist-netting capture and from acoustic recordings to identify pairwise associations that were detected more frequently than expected under a null distribution, and compared the strength of these associations between old-growth and secondary forest Amazonian tropical forest. We also used the pairwise strength associations to visualize the social network structure and its changes between habitat types. We found many strongly positive interactions between species, but no evidence of repulsion. Network analyses revealed several modules of species that broadly agree with the subjective groupings described in the ornithological literature. Furthermore, both network structure and association strength changed drastically with habitat disturbance, with the formation of a few new associations but a general trend towards the breaking of associations between species. Our results show that social grouping in birds is real and may be strongly affected by habitat degradation, suggesting that the stability of the associations is threatened by anthropogenic disturbance.
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Ecology and restoration of Sumatran tigers in forest and plantation landscapesSunarto, Sunarto 25 April 2011 (has links)
Tigers (Panthera tigris Linnaeus, 1758) are in danger of extinction. Their populations have declined from ~100,000 to only ~3,000 individuals in a century and their habitat has shrunk to less than 7% of the historic range. Of the five extant tiger subspecies, the Sumatran tiger (Panthera tigris sumatrae Pocock, 1929) is the most seriously threatened. Currently determined as Critically Endangered under IUCN criteria, the Sumatran tiger is likely to become extinct unless effective conservation measures are enacted. Threats to the tiger include habitat destruction, killing due to conflict with humans and livestock, and poaching for illegal wildlife trade.
Long-term survival of Sumatran tigers depends largely on the effectiveness of current conservation efforts in every tiger landscape. Successful conservation and management require accurate information on ecology of the species upon which decisions can be based. This study investigated basic ecological aspects of tigers and developed strategies for management and restoration to improve tiger viability in the Central Sumatra landscape. This landscape is comprised of natural forests and plantations managed for timber and agricultural commodities.
The first chapter assesses the variation in tiger abundance across forest types in Southern Riau, and over time in Tesso Nilo National Park, all in Central Sumatra. Using camera traps, my team and I systematically sampled five blocks representing three major forest types in the region: peat land, flat lowland, and hilly lowland. I found that tiger abundance varied by forest type and through time. Excluding two sampling blocks where no tigers were photographed, the lowest tiger density was in peat land forest of Kerumutan, and the highest density was in the flat lowland forest of Tesso Nilo. Repeated sampling in the newly established Tesso Nilo National Park documented a trend of increasing tiger density (SE) from 0.90 (0.38) individuals/100 km2 in 2005 to 1.70 (0.66) individuals/100 km2 in 2008. Overall, tiger densities from this study were lower than most previous estimates from other parts of Sumatra. The trend of increasing tiger density in Tesso Nilo, however, suggests that the tiger population could be augmented by protection of habitats that were previously logged and severely disturbed.
The second chapter examines the occupancy and habitat-use of the tiger across the major landcover types (natural forest, acacia plantation, oilpalm plantation, rubber plantation, and mixed agriculture). I found that tigers used some plantation areas, although they significantly preferred forests over plantations. In all landcover types, sites with tiger detections had thicker understory cover than sites without tiger detection. Modeling tiger occupancy while recognizing that probability of detection is not always perfect, I found that tiger occupancy covaried positively and significantly with altitude and negatively, but not significantly, with distance-to-forest-cores. Probability of habitat use by tigers covaried positively and significantly with understory cover and altitude, and negatively and significantly with human settlement and landcover rank. The results suggested that with adjustments in plantation management, tigers could use or roam through plantations within the habitat mosaic provided that the plantations had adequate understory cover and low level of human activity. They also could use riparian forests (as corridors) and smaller forest patches (as stepping stones) to travel between the main habitat patches across the forest and plantation landscape.
The third chapter investigates the ecological characteristics and possible inter-specific interactions among wild felids, including tigers and smaller cats, based on data collected using systematic camera trapping in combination with information on their natural history. I found that despite overlap in resource needs of the five felid species, each appears adapted to specific environmental conditions allowing coexistence with other felids. The five felid species used statistically different elevations, with the golden cat found to inhabit the highest elevation. Two-species occupancy models showed that only leopard cats were found to co-occur with other felid species more frequently than expected by chance under independence. Species of similar size or eating similar-sized prey generally tended to have low coefficients of temporal activity overlap, suggesting avoidance. Temporal avoidance is likely occurring in three pairs of felids, namely clouded leopards and golden cats, clouded leopards and marbled cats, and marbled cats and leopard cats. Based on the differences in morphological and ecological characteristics, and on patterns of spatial and temporal occurrence, I identified six possible mechanisms by which felids in Central Sumatra maintain coexistence. I discussed the implications of this study for management, focusing on how to balance diversity and abundance of felids.
The fourth chapter presents the tiger distribution models as a case study to illustrate the importance of accounting for uncertainty in species distribution mapping. I applied four modeling approaches, differing in how the response variable (tiger presence) is constructed and used in the models. I compared the performance and output of different models based on the relative importance of variables, descriptive statistics of the predictions, cross comparison between models using an error matrix, and validation using tiger presence data collected from independent surveys. All models consistently identified forest area within the grid as one of the most important variables explaining tiger probability of occurrence. Three models identified altitude as another important factor. While the four models were consistent in predicting relatively high probability of tiger occurrence for high elevation forest areas such as Rimbang Baling and Bukit Tigapuluh, they generally had a lower level of agreement in predictions for low elevation areas, particularly the peat land in the northeastern part of the study area. Based on the results of cross evaluation of the predictions among models and validation with the independent data, I considered the occupancy model to be superior to the others. If data collection format permits, I advocate the use of occupancy instead of the other modeling techniques to develop predictive species distribution maps.
The last chapter constructs a strategy to restore the tiger population across the ecosystem of Central Sumatra through integration of knowledge on tiger ecology from previous chapters with consideration of the ecological conditions of the landscape in the region. The strategy combines existing knowledge of tiger conservation and regional ecosystem restoration. It recognizes the limitations and challenges of traditional nature protection and considers existing and new opportunities. Emerging opportunities and new mechanisms, such as direct and indirect economic incentives for nature conservation and restoration, are taken into account. These, coupled with increased awareness of the stakeholders, better policies and implementation of good governance, and the willingness and know-how to maintain coexistence with wildlife among the local people, are expected to support and accelerate the recovery of tigers and their ecosystem. / Ph. D.
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Étude du polymorphisme intra- et inter-spécifique du gène β-tubuline chez des espèces de champignons mycorhiziens à arbuscules en vue de développer des marqueurs moléculairesZeramdini, Nadia 10 1900 (has links)
Les champignons mycorhiziens à arbuscules (CMA), classés dans le phylum Glomeromycota, ne peuvent pas être facilement identifiés par la morphologie de leurs spores et leurs mycélia à l'intérieur ou à l'extérieur des racines de leurs hôtes. Ce problème fondamental d'identification rend l'étude de leur diversité, en particulier dans leur habitat naturel (sol et racine) extrêmement difficile.
Les gènes ribosomaux ont été largement utilisés pour développer des amorces spécifiques et en inférer des arbres phylogénétiques. Cependant, ces gènes sont très polymorphes et
existent en plusieurs copies dans le génome des CMA, ce qui complique l’interprétation des résultats.
Dans notre étude, nous avons étudié le polymorphisme intra- et inter-spécifique du gène β-tubuline, présent en faible nombre de copies dans le génome des CMA, afin d’obtenir de
nouvelles séquences nucléotidiques pour développer des marqueurs moléculaires. Les
gènes β-tubuline amplifiés à partir de l'ADN génomique de cinq espèces du genre Glomus
ont été clonés et séquencés. L’analyse des séquences indique un polymorphisme intraspécifique chez trois espèces de CMA. Deux séquences paralogues très variables ont été nouvellement identifiées chez les G. aggregatum, G. fasciculatum et G. cerebriforme.
Aucun polymorphisme n’a été détecté chez les G. clarum et G. etunicatum. Toutes les
séquences montrent la présence de deux introns hautement variables. La majorité des
substitutions ont été localisées dans les exons et sont synonymes à 90%. La conservation des acides aminés suggère un niveau élevé de sélection négative sur le gène β-tubuline et
nous permet de confirmer que les CMA représentent un ancien groupe fongique (400
million d’années). L’analyse phylogénétique, réalisée avec vingt et une séquences
nucléotidiques du gène β-tubuline, a révélé que les séquences des Glomaceae forment un
groupe monophylétique bien supporté, avec les Acaulosporaceae et Gigasporaceae comme
groupe frère. Les séquences paralogues nouvellement identifiées chez les G. aggregatum et G. fasciculatum n'ont pas été monophylétiques au sein de chaque espèce. Les
oligonucléotides ont été choisis sur la base des régions variables et conservées du gène β-tubuline. Le test PCR des amorces β-Tub.cerb.F/ β-Tub.cerb.R a révélé des bandes
spécifiques de 401 pb pour les séquences paralogues du G. cerebriforme. Deux paires
d’amorces ont été développées afin d’identifier les séquences du groupe nommé Tub.1. Les tests PCR nous ont permis d’identifier certaines séquences du groupe Tub.1. Une paire d’amorce β-Tub.2.F/ β-Tub.2.R nous a permis d’identifier certaines séquences paralogues du groupe nommé Tub.2.
L’analyse d’autres gènes combinée à celle du gène β-tubuline permettra le développement
de marqueurs moléculaires plus spécifiques pour l’identification de CMA. / Arbuscular mycorrhizal fungi (AMF) are classified in the phylum Glomeromycota. This
fungal group cannot be easily identified using morphology of their spores and hyphae
inside or outside plant-roots. This fundamental problem renders the study of their diversity extremely difficult, particularly in their natural habitat (soil and roots).
The ribosomal genes have been widely used to develop specific primers and to infer
phylogenetic trees. However, these genes are highly polymorphic and exist in multiple
copies in the genome of the AMF. This leads misinterpretation of the results.
In our study, we analysed the intra- and inter specific polymorphism of the β-tubulin gene, which is present in low copy number in AMF genome, to obtain further nucleotide
sequences to develop molecular markers.
β-tubulin genes were sequenced from genomic DNA of five Glomus species. PCR amplified β-tubulin genes were cloned and sequenced. Intra- and inter-specific polymorphism analyses indicate the polymorphic nature of β-tubulin gene in three AMF species. Two highly variable β-tubulin paralogs were newly identified in G. aggregatum,
G. fasciculatum and G. cerebriforme. No evidence for the presence of paralogs was found in G. clarum and G. etunicatum. All AMF sequences show the presence of two introns, which are highly variable. The majority of substitutions are located in the exons and 90% are synonymous. The conservation of amino-acids level suggests a high level of negative selection acting on the β-tubulin gene and allows us to consider that the AMF represent an ancient fungal group (400 million years). A phylogenetic analysis, carried out with twentyone
β-tubulin nucleotidic sequences, revealed that the sequences of Glomeraceae form a
highly supported monophyletic group with Acaulosporaceae and Gigasporaceae as sistergroup.
The newly identified paralogs from G. aggregatum and G. fasciculatum were not
found to be monophyletic within each species. Oligonucleotides were designed in the conserved and variable regions. PCR amplification test of β-Tub.cerb.F / β-Tub.cerb.R revealed specific bands of 401 bp for the G. cerebriforme paralogs. Two pairs of primers were developed to identify sequences of the group named Tub.1. PCR tests have allowed us
to identify certain sequences of Tub.1 group. A primer pair of β-Tub.2.F / β-Tub.2.R we identified some sequences paralogous group named Tub.2. Analysis of other genes combined with that of β-tubulin gene enable the development of more specific molecular markers for AMF identification.
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