ICB - Artigos publicados em periódicos

URI Permanente para esta coleção

http://200.137.215.59//handle/ri/1399

Navegar

Agora exibindo 1 - 20 de 1387

Process-based modelling shows how climate and demography shape language diversity
(2017) Gavin, Michael C.; Rangel, Thiago Fernando Lopes Valle de Britto; Bowern, Claire; Colwell, Robert Knight; Kirby, Kathryn R.; Botero, Carlos A.; Dunn, Michael; Dunn, Robert R.; McCarter, Joe; Coelho, Marco Túlio Pacheco
Aim Two fundamental questions about human language demand answers: why are so many languages spoken today and why is their geographical distribution so uneven? Although hypotheses have been proposed for centuries, the processes that determine patterns of linguistic and cultural diversity remain poorly understood. Previous studies, which relied on correlative, curve-fitting approaches, have produced contradictory results. Here we present the first application of process-based simulation modelling, derived from macroecology, to examine the distribution of human groups and their languages. Location The Australian continent is used as a case study to demonstrate the power of simulation modelling for identifying processes shaping the diversity and distribution of human languages. Methods Process-based simulation models allow investigators to hold certain factors constant in order to isolate and assess the impact of modelled processes. We tested the extent to which a minimal set of processes determines the number and spatial distribution of languages on the Australian continent. Our model made three basic assumptions based on previously proposed, but untested, hypotheses: groups fill unoccupied spaces, rainfall limits population density and groups divide after reaching a maximum population. Results Remarkably, this simple model accurately predicted the total number of languages (average estimate 406, observed 407), and explained 56% of spatial variation in language richness on the Australian continent. Main conclusions Our results present strong evidence that current climatic conditions and limits to group size are important processes shaping language diversity patterns in Australia. Our study also demonstrates how simulation models from macroecology can be used to understand the processes that have shaped human cultural diversity across the globe.
Spatial variation in direct and indirect effects of climate and productivity on species richness of terrestrial tetrapods
(2021) Pereira, Elisa Barreto; Rangel, Thiago Fernando Lopes Valle de Britto; Coelho, Marco Túlio Pacheco; Cassemiro, Fernanda Aparecida da Silva; Zimmermann, Niklaus E.; Graham, Catherine Helen
Aim: We aimed to dissect the spatial variation of the direct and indirect effects of climate and productivity on global species richness of terrestrial tetrapods. Location: Global. Time period: Present. Major taxa studied: Terrestrial tetrapods. Methods: We used a geographically weighted path analysis to estimate and map the direct and indirect effects of temperature, precipitation and primary productivity on species richness of terrestrial tetrapods across the globe. Results: We found that all relationships shift in magnitude, and even in direction, among taxonomic groups, geographical regions and connecting paths. Direct effects of temperature and precipitation are generally stronger than both indirect effects mediated by productivity and direct effects of productivity. Main conclusions: Richness gradients seem to be driven primarily by effects of cli mate on organismal physiological limits and metabolic rates rather than by the amount of productive energy. Reptiles have the most distinct relationships across tetrapods, with a clear latitudinal pattern in the importance of temperature versus water.
Exceptions to the rule: relative roles of time, diversification rates and regional energy in shaping the inverse latitudinal diversity gradient
(2021) Cerezer, Felipe Osmari; Machac, Antonin; Rangel, Thiago Fernando Lopes Valle de Britto; Dambros, Cristian de Sales
Aim: Inverse latitudinal diversity gradients (i-LDGs), whereby regional richness peaks outside the tropics, have rarely been investigated, and their causes remain unclear. Here, we investigate three prominent explanations, postulating that species-rich re gions have had: (1) longer time to accumulate species; (2) faster diversification; and (3) more energy to support species-rich communities. These mechanisms have been shown to explain the tropical megadiversity, and we examine whether they can also explain i-LDG. Location: Global. Time period: Contemporary. Major taxa studied: Amphibians, birds and mammals. Methods: We estimated the time for species accumulation, regional diversification rates and regional energy for six tetrapod taxa (c. 800 species). We quantified the rel ative effects and interactions among these three classes of variables, using variance partitioning, and confirmed the results across alternative metrics for time (community phylometrics and BioGeoBEARS), diversification rates (BAMM and DR) and regional energy (past and current temperature, and productivity). Results: Although regional richness across each of the six taxa peaked in the temper ate region, it varied markedly across hemispheres and continents. The effects of time, diversification rates and regional energy varied greatly from one taxon to another, but high diversification rates generally emerged as the best predictor of high regional richness. The effects of time and regional energy were limited, with the exception of salamanders and cetaceans. Main conclusions: Together, our results indicate that the causes of i-LDG are highly taxon specific. Consequently, large-scale richness gradients might not have a univer sal explanation, and different causal pathways might converge on similar gradients. Moreover, regional diversification rates might vary dramatically between similar envi ronments and, depending on the taxon, regional richness might or might not depend on the time for species accumulation. Collectively, these results underscore the com plexity behind the formation of richness gradients, which might involve a symphony of variations on the interplay of time, diversification rates and regional energy.
The latitudinal diversity gradient: novel understanding through mechanistic eco-evolutionary models
(2019) Pontarp, Mikael; Bunnefeld, Lynsey; Cabral, Juliano Sarmento; Etienne, Rampal Stefan; Fritz, Susanne A.; Gillespie, Rosemary; Graham, Catherine Helen; Hagen, Oskar; Hartig, Florian; Shan, Huang; Rangel, Thiago Fernando Lopes Valle de Britto
The latitudinal diversity gradient (LDG) is one of the most widely studied patterns in ecology, yet no consensus has been reached about its underlying causes. We argue that the reasons for this are the verbal nature of existing hypotheses, the failure to mechanistically link interacting ecological and evolutionary processes to the LDG, and the fact that empirical patterns are often consistent with multiple explanations. To address this issue, we synthesize current LDG hypotheses, uncovering their eco-evolutionary mechanisms, hidden assumptions, and commonalities. Furthermore, we propose mechanistic eco-evolutionary modeling and an inferential approach that makes use of geographic, phylogenetic, and trait-based patterns to assess the relative importance of different processes for generating the LDG.
Neutral biogeography of phylogenetically structured interaction networks
(2017) Coelho, Marco Túlio Pacheco; Rodrigues, João Fabrício Mota; Rangel, Thiago Fernando Lopes Valle de Britto
Effects of neutrality and productivity on mammal richness and evolutionary history in Australia
(2019) Coelho, Marco Túlio Pacheco; Dambros, Cristian de Sales; Rosauer, Dan F.; Pereira, Elisa Barreto; Rangel, Thiago Fernando Lopes Valle de Britto
Explaining how heterogeneous spatial patterns of species diversity emerge is one of the most fascinating questions of biogeography. One of the great challenges is revealing the mechanistic effect of environmental variables on diversity. Correlative analyses indicate that productivity is associated with taxonomic, phylogenetic, and functional diversity of communities. Surprisingly, no unifying body of theory have been developed to understand the mechanism by which spatial variation of productivity affects the fundamental processes of biodiversity. Based on widely discussed verbal models in ecology about the effect of productivity on species diversity, we developed a spatially explicit neutral model that incorporates the effect of primary productivity on community size and confronted our model's predictions with observed patterns of species richness and evolutionary history of Australian terrestrial mammals. The imposed restrictions on community size create larger populations in areas of high productivity, which increases community turnover and local speciation, and reduces extinction. The effect of productivity on community size modeled in our study causes higher accumulation of species diversity in productive regions even in the absence of niche-based processes. However, such a simple model is not capable of reproducing spatial patterns of mammal evolutionary history in Australia, implying that more complex evolutionary mechanisms are involved. Our study demonstrates that the overall patterns of species richness can be directly explained by changes in community sizes along productivity gradients, supporting a major role of processes associated with energetic constraints in shaping diversity patterns.
Neutral community dynamics and the evolution of species interactions
(2018) Coelho, Marco Túlio Pacheco; Rangel, Thiago Fernando Lopes Valle de Britto
A contemporary goal in ecology is to determine the ecological and evolutionary processes that generate recurring structural patterns in mutualistic networks. One of the great challenges is testing the capacity of neutral processes to replicate observed patterns in ecological networks, since the original formulation of the neutral theory lacks trophic interactions. Here, we develop a stochastic-simulation neutral model adding trophic interactions to the neutral theory of biodiversity. Without invoking ecological differences among individuals of different species, and assuming that ecological interactions emerge randomly, we demonstrate that a spatially explicit multitrophic neutral model is able to capture the recurrent structural patterns of mutualistic networks (i.e., degree distribution, connectance, nestedness, and phylogenetic signal of species interactions). Nonrandom species distribution, caused by probabilistic events of migration and speciation, create nonrandom network patterns. These findings have broad implications for the interpretation of niche-based processes as drivers of ecological networks, as well as for the integration of network structures with demographic stochasticity.
Ecological niche models predict the potential distribution of the exotic rotifer Kellicottia bostoniensis (Rousselet, 1908) across the globe
(2021) Mantovano, Tatiane; Diniz, Leidiane Pereira; Conceição, Eliezer de Oliveira da; Rosa, Jonathan da; Bonecker, Claudia Costa; Fernandes, Dayani Bailly; Ferreira, José Hilário Delconte; Rangel, Thiago Fernando Lopes Valle de Britto; Lansac Tôha, Fábio Amodêo
The invasion of non-native species is one of the major factors influencing the loss of biodiversity. The rotifer Kellicottia bostoniensis, which is native to North America, has been registered in several other countries and on other continents. We investigated the main climatic-environmental variables suitable for the potential distribution of K. bostoniensis and, hence, the areas of non-native regions where it could spread. We used different statistical niche models within an ensemble forecasting approach to estimate environmental suitability and the potential global distribution area of K. bostoniensis. Precipitation in the driest month and temperature in the coldest month were the most important variables in predicting the distribution of the species. Our predictions indicated that countries with high invasive potential included Argentina and Brazil (South America), Croatia, France, and Germany (Europe). The results also revealed that many areas with high invasive potential, such as East Asia, have no recorded occurrences yet. Our study provides important information for implement management measures to deal with the problems of the spread of K. bostoniensis through ballast water and aquaculture in countries and regions highly susceptible to invasion (mainly areas that the species has not yet reached), thus providing useful information for decision making.
The conservation of migratory fishes in the second largest river basin of South America depends on the creation of new protected areas
(2021) Fernandes, Dayani Bailly; Silva, Valéria Flávia Batista da; Cassemiro, Fernanda Aparecida da Silva; Silva, Priscila Lemes de Azevedo; Graça, Weferson Júnio da; Oliveira, Anielly Galego de; Couto, Edivando Vitor do; Ferreira, José Hilário Delconte; Ré, Reginaldo; Rangel, Thiago Fernando Lopes Valle de Britto; Agostinho, Angelo Antonio
Freshwater ecosystems, providing valuable goods and services to humans, have been subjected to multiple human impacts, among which climate change plays a central role in threats to species. It is expected that protected areas, the cornerstone of biodiversity conservation efforts, will assume a decisive role in protecting freshwater species from the impacts of climate change. This study assessed the effects of climate change on migratory fish of the second largest neotropical river basin, evaluating the effectiveness of protected areas in safeguarding fish species, and hence the ecological functions that they perform and the ecosystem resources that they provide. The present range of 23 migratory fish of economic interest in the Paraná–Paraguay basin was estimated and the responses to future climatic shifts projected to the middle and end of the 21st century were examined, quantifying predictive uncertainties. Changes and losses of climatically suitable areas will trigger severe contractions in range, with the greatest impact on the most valuable species in commercial fishing, where range losses are likely to surpass 65% in the future. The main channel of the Upper Paraná River and tributaries of its left margin are projected to serve as climatic refuges for many species, and such regions are not affected by high predictive uncertainty. The results revealed that protected areas do not sufficiently protect migratory fish at present, and that they will continue to offer negligible protection in the face of climate change. This study alerts decision makers to the potential damage to inland fishery resources from climate change and provides useful information to guide conservation strategies spatially. We advocate that the creation of new protected areas and the redesign of the existing network to encompass regions that maximize current and future occupancy of migratory fish are crucial to conserve the valuable ecological, societal, and economic benefits that they provide.
A global analysis of the susceptibility of river basins to invasion of a freshwater zooplankton (Daphnia lumholtzi)
(2021) Mantovano, Tatiane; Fernandes, Dayani Bailly; Ferreira, José Hilário Delconte; Conceição, Eliezer de Oliveira da; Cassemiro, Fernanda Aparecida da Silva; Campos, Ramiro de; Mormul, Roger Paulo; Rangel, Thiago Fernando Lopes Valle de Britto; Lansac Toha, Fabio Amodeo
Climate change and species invasions pose serious threats to biodiversity. Daphnia lumholtzi Sars, 1885, a cladoceran species native to Africa, Asia, and Oceania, has successfully invaded large sections of North and South America, there is evidence that the increase in the Earth's temperature and the number of reservoirs have facilitated this process. In this context, our study evaluated the effects of climate change on the invasive potential of D. lumholtzi, identifying the environmental suitability of non-native river basins around the world to invasion by this species. Using ecological niche modelling, we predicted potential distribution areas of D. lumholtzi in non-native continents at the present time, in 2050 and 2080. For future scenarios we considered two hypotheses of greenhouse gas emission: extreme (8.5 representative concentration pathways) and moderate (4.5 representative concentration pathways). We used different algorithms in niche models within the ensemble forecast approach to estimate the potential distribution of D. lumholtzi river basins worldwide. Furthermore, we developed a susceptibility index, that uses the presence of D. lumholtzi, its suitability information, area, and number of reservoirs to evaluate the susceptibility to invasion for each river basin. Our predictions showed that future climate change will have a strong influence on the invasive potential of D. lumholzti, potentially expanding its distribution in eastern North America and boosting invasion across Europe, especially at the end of the century. The susceptibility index also showed that many river basins that presently are not vulnerable to invasion by this species will become susceptible to invasion, these basins lie mainly in Europe. Our results will be useful for monitoring and mitigating the spread of this species, especially for river basins identified as highly susceptible to invasion. Thus, we suggested that D. lumholtzi should be a high priority for monitoring and preventive actions against invasion of these river basins. We also suggest that better risk assessments, that include invasive species and reservoirs, should be a priority in national energy development plans.
A global test of the subsidized island biogeography hypothesis
(2020) Domingos, André Menegotto; Rangel, Thiago Fernando Lopes Valle de Britto; Schrader, Julian; Weigelt, Patrick; Kreft, Holger
Aim The decreasing capacity of area to predict species richness on small islands (the small-island effect; SIE) seems to be one of the few exceptions of the species–area relationship. While most studies have focused on how to detect the SIE, the underlying ecological factors determining this pattern remain largely unexplored. Here, we evaluate one of the few mechanisms proposed to explain the SIE, the subsidized island biogeography hypothesis, which posits that marine productivity around small islands may alter their expected species richness. Location Seven hundred and ninety islands worldwide, including 420 islands < 1 km2. Time period Present. Major taxa studied Angiosperms. Methods We applied iterative partial regression to determine the effects of island area and marine productivity on plant species richness for islands of varying sizes. We also employed geographically weighted regression to account for non-stationarity in the marine productivity effects. Lastly, we used estimates of ammonia emissions based on nutrient excretion by seabird colonies from a subset of 66 islands to evaluate the effects of marine resources deposition on angiosperm species richness. Results We found no effect of marine productivity on insular species richness, at both regional and global scales. In all models, area emerged as the only predictor of plant species richness. A weak contribution of marine productivity was only detectable in models with a low number of islands, but this effect was independent of island size. Although nutrient deposition significantly contributes to explaining plant diversity, this effect was also independent of island size. Main conclusions Our study demonstrates that marine productivity has no general effect on plant species richness of small islands worldwide. Although marine-derived resources may still contribute to species richness variation, this effect does not seem to be restricted to small islands. Overall, our results do not provide support for the subsidized island biogeography hypothesis.
Environmental factors explain the spatial mismatches between species richness and phylogenetic diversity of terrestrial mammals
(2019) Pereira, Elisa Barreto; Graham, Catherine Helen; Rangel, Thiago Fernando Lopes Valle de Britto
Aim Explore the spatial variation of the relationships between species richness (SR), phylogenetic diversity (PD) and environmental factors to infer the possible mechanisms underlying patterns of diversity in different regions of the globe. Location Global. Time period Present day. Major taxa studied Terrestrial mammals. Methods We used a hexagonal grid to map SR and PD of mammals and four environmental factors (temperature, productivity, elevation and climate-change velocity since the Last Glacial Maximum). We related those variables through direct and indirect pathways using a novel combination of path analysis and geographically weighted regression to account for spatial non-stationarity of path coefficients. Results Species richness, PD and environmental factors relate differently across the geographical space, with most relationships varying in both magnitude and direction. Species richness is associated with lower PD in much of the tropics and in the Americas, which reflects the tropical origin and the recent diversification of some mammalian clades in these regions. Environmental effects on PD are predominantly mediated by their effects on SR. But once richness is controlled for, the relationships between environmental factors and PD (i.e. PDSR) highlight environmentally driven changes in species composition. Environmental–PDSR relationships suggest that the relative importance of different mechanisms driving biodiversity shifts spatially. Across most of the globe, temperature and productivity are the strongest predictors of richness, whereas PDSR is best predicted by temperature. Main conclusions Richness explains most spatial variation in PD, but both dimensions of biodiversity respond differently to environmental conditions across the globe, as indicated by the spatial mismatches in the relationships between environmental factors and these two types of diversity. We show that accounting for spatial non-stationarity and environmental effects on PD while controlling for richness uncovers a more complex scenario of drivers of biodiversity than previously observed.
DNA damage in peripheral blood lymphocytes and association with polymorphisms in the promoter region of the CYP2E1 gene in alcoholics from Central Brazil
(2016) Ramos, Jheneffer Sonara Aguiar; Alves, Alessandro Arruda; Lopes, Mariana Paiva; Pedroso, Thays Millena Alves; Felício, Leandro Prado; Carvalho, Wanessa Fernandes; Franco, Fernanda Craveiro; Melo, Caroline Oliveira de Araújo; Gonçalves, Macks Wendhell; Soares, Thannya Nascimento
DNA damage caused by the accumulation of bio-products generated in the biotransformation of ethanol to acetaldehyde mediated by the CYP2E1 enzyme has been studied. To evaluate DNA damage in peripheral blood lymphocytes and the possible association with polymorphisms in the promoter region of the CYP2E1 gene, we performed a case-control study including 75 alcoholics and 59 individuals who consume alcohol socially. Alcoholics were previously diagnosed by the Psychosocial Care Center – Alcohol and Drugs (CAPS A/D) in the city of Goiania, Goias state, Central Brazil. DNA damage was evaluated by comet assay. The analysis of the rs3813867, rs2031920, and rs2031921 polymorphisms in the promoter region of CYP2E1 gene was performed by Sanger sequencing. Men older than 35 years old were the most common alcoholics. We found increased DNA damage in the case group, compared to the control group (p < 0.001). Alcoholics who were heterozygous in the rs3813867, rs2031920, and rs2031921 polymorphisms showed higher DNA damage (tail length and olive tail moment), compared to individuals with the homozygous non-mutated allele. Previous studies have shown that polymorphisms in the promoter region of the CYP2E1 gene could cause higher CYP2E1 transcriptional activity, increasing enzyme activity compared with nondrinkers, indicating that the presence of the mutated allele (heterozygous or homozygous) may be associated with higher alcohol metabolic rates and therefore show increased acetaldehyde levels after alcohol consumption, which then can exert its carcinogenic effect.
Evaluating the OGG1 rs1052133 and rs293795 polymorphisms in a sample of rural workers from Central Brazil population: a comparative approach with the 1000 Genomes Project
(2018) Silva, Daniela de Melo e; Alves, Alessandro Arruda; Nunes, Hugo Freire; Ramos, Jheneffer Sonara Aguiar; Franco, Fernanda Craveiro; Soares, Thannya Nascimento
Brazilian population is one of the largest consumers of pesticides in the world, especially the Central Brazil population. Thus, the aim of this study was to evaluate the frequency of genotypes, alleles, haplotypes, and the linkage disequilibrium (DL) of the OGG1 gene in rural workers from Central Brazil, comparing with the populations of the 1000 genome. Three hundred thirty healthy individuals not related and randomly selected were included in this study. We obtained genomic DNA from peripheral blood lymphocytes. The 748-bp OGG1 gene was amplified by PCR and sequenced. Of the 330 individuals, 215 (65%) were males and 115 (35%) were females. There were no differences in the distribution of the rs1052133 and rs293795 with age and sexes. Haplotypes containing only conserved T/C alleles were the most common in our population. The frequency of the mutant alleles of rs1052133 and rs293795, in our population, was 20% and 30%, respectively, and it is noteworthy, worldwide, that mutant alleles are commonly associated to an increased risk for the development of cancer, specially due to direct or indirect contact to pesticides, as occurs in rural workers of Central Brazil population.
Unraveling CYP2E1 haplotypes in alcoholics from Central Brazil: A comparative study with 1000 genomes population
(2018) Ramos, Jheneffer Sonara Aguiar; Felício, Leandro Prado; Alves, Alessandro Arruda; Lopes, Mariana Paiva; Soares, Thannya Nascimento; Silva, Daniela de Melo e
We evaluated genetic variability of single nucleotide polymorphisms (SNPs) situated in the CYP2E1 gene promoter in alcoholics. We also compared 1000 Genomes Project of CYP2E1 polymorphisms with frequencies of genotypes and haplotypes. Eight variation points were exclusively found in Brazilians. The allelic distributions of the rs3813867, rs2031920 and rs2031921 polymorphisms in the CYP2E1 showed that the wild alleles (G, C, T, respectively) had higher frequencies in both groups, alcoholic (96%, 96%, 96%) and a control group (95.8%, 94.9%, 94.9%), when compared to the mutated allele (C, T, C, respectively). The variation points, rs3813867, rs2031920 and rs2031921 showed strong linkage disequilibrium (LOD ≥ 2, D ' = 1). South Asian populations presented larger LD blocks compared to the other populations. Our results showed that the allelic frequencies were markedly different among ethnicities and have contributed to the knowledge regarding the distribution among ethnic groups, being associated to alcohol consumption worldwide.
Demographical expansion of Handroanthus ochraceus in the Cerrado during the Quaternary: implications for the genetic diversity of Neotropical trees
(2018) Vitorino, Luciana Cristina; Ribeiro, Matheus de Souza Lima; Terribile, Levi Carina; Collevatti, Rosane Garcia
Phylogeographical studies provide insights into the dispersal dynamics of species needed to understand the effects of Quaternary climate changes on the spatial patterns of genetic diversity. We used a multi-model inference approach coupling ecological niche modelling (ENM) with a relaxed random walk model to reconstruct the spatio-temporal history of lineage dispersal of the Neotropical tree species Handroanthus ochraceus. We sampled 24 populations throughout the Cerrado Biome and analysed polymorphisms at three intergenic chloroplast regions and ITS. Coalescent analyses revealed demographical expansion since c. 380 ka. Although ENM predicted no range expansion, coalescent simulations reinforce the pattern of range expansion because demographical expansion was the most likely scenario able to produce the observed spatial pattern of genetic diversity of H. ochraceus. Its most recent common ancestor dated from ~1.9 Ma, and lineages cyclically dispersed from the Southeast and West towards Central–West Brazil. Most dispersal events occurred from populations at the edges of the Cerrado towards Central Brazil. Populations at the edge of the historical refugium show higher genetic diversity and were the source of migrants to central populations. A wide historical climatic refugium through time for H. ochraceus may have allowed dispersal of lineages among populations of Central Brazil, maintaining their historical connectivity and genetic diversity.
Phylogenomics of the palm tribe lepidocaryeae (Calamoideae: Arecaceae) and description of a new species of Mauritiella
(2021) Torres Jimenez, María Fernanda; Prata, Eduardo Magalhães Borges; Zizka, Alexander; Haft, Mario Eric Cohn; Oliveira, Ayslaner Victor Gallo de; Sousa, Thaise Emilio Lopes de; Chazot, Nicolas; Couvreur, Thomas L. P.; Kamga, Suzanne Mogue; Sonké, Bonaventure; Covellatti, Rosane Garcia
The palm tribe Lepidocaryeae (Arecaceae) comprises seven genera and 51 currently accepted species that are distributed in lowland tropical forests and savannas across Africa and the Americas. Subtribal relationships within Lepidocaryeae have been a persistent challenge, limiting our understanding of its systematics, morphology, and biogeography. Several aspects make the tribe an ideal system to study plant evolution and diversity: it is well-represented in the fossil record as a prolific pollen producer, its continental diversity contradicts common biodiversity patterns of lower species richness in Africa in comparison to South America, and it contains one of the most abundant Amazonian tree species, Mauritia flexuosa. Here, we investigated the systematics of the tribe by sampling 122 individuals representing 42 species (82% of the tribe), using target sequence capture. We recovered nearly 10,000 single nucleotide polymorphisms from nuclear and plastid DNA across 146 target sequences to separately infer a phylogenomic tree. Our results strongly support inter-generic and inter-specific relationships, where a majority of nodes were resolved with over 90% bootstrap support. We also identify strong phylogenetic support for the recognition of a new species from central and south Amazonia, Mauritiella disticha. The distichous phyllotaxy is diagnostic of the species within the genus. Rare and currently only known from the middle-lower Madeira River basin in the state of Amazonas, Brazil, M. disticha is restricted to open vegetation and forest edges growing in white sand habitats with saturated or well-drained soils. Our preliminary red list assessment suggests its threatened status to be vulnerable (VU). We use our phylogenomic inference to define and contextualize systematic relationships in the tribe, and present a formal species description
Holocene climate changes explain the spatial pattern in genetic diversity in populations of Cyperus papyrus from Southeast Africa wetlands
(2022) Maxombe, Elias Luis; Vieira, Lucas Donizetti; Sierens, Tim; Triest, Ludwig; Collevatti, Rosane Garcia
Wetlands are one of the most threatened ecosystems in the world because more than 70% of the area worldwide has been lost since 1900. Wetland plant species rely greatly on water for seeds and propagules, which may lead to a downstream unidirectional dispersal and accumulation of genetic diversity downstream. However, several species show no support for unidirectional genetic diversity, revealing the complexity of population dynamics and gene flow in wetlands. Here, we used microsatellite loci to address how the past demographic dynamics shaped the contemporary spatial pattern in genetic diversity and population structure of Cyperus papyrus in wetlands of Southeast Africa. Using spatially explicit analysis and coalescent modelling, we found no support for unidirectional dispersal. Instead, we found higher genetic diversity in populations upstream than downstream in the river basin. We also found high admixture among populations, most likely due to connections between adjacent river basins during sporadic floods, and ongoing gene flow due to bird-mediated seed dispersal. Our results suggest stepping-stone migration due to strong isolation-by-distance, but not necessarily unidirectional. Moreover, the past demographic dynamics in the Holocene shaped the current pattern of genetic diversity and structure, leading to higher genetic diversity in populations upstream the Zambezi river basin. Our results also point to the very low genetic diversity of C. papyrus populations in Southeast Africa and the need for management and conservation strategies to guarantee the long-term persistence of the species in the region.
Traditional management affects the phenotypic diversity of fruits with economic and cultural importance in the Brazilian Savanna
(2018) Sousa Júnior, José Ribamar; Collevatti, Rosane Garcia; Lins Neto, Ernani Machado de Freitas; Peroni, Nivaldo; Albuquerque, Ulysses Paulino
The management of plant populations may cause phenotypic changes in the characteristics of a plant that is targeted by human selection over time, which can therefore lead to the domestication process. Studies about this approach have shown that managed plant populations have the most interesting features for use by human populations because they have more productive plants and larger fruits. To evaluate this effect, the traditional management of Caryocar coriaceum Wittm (pequi) in the Chapada do Araripe region of Northeast Brazil was studied by using a morphometric and ethnobotanical approach. A morphometric analysis of the fruits was conducted, during which the plants were recorded to the following three different management regimes: cultivation, in situ management (collection) and incipient management (the tolerance and protection of individuals). To test the hypothesis that people perceive natural morphological variations in the fruits, local people perception was assessed through different methods. To assess the possible influence of management regimes on fruit morphology, 40 reproductive individuals cultivated, 40 managed in situ and 36 individuals under incipient management were randomly selected, and 20 fruits of each were collected for the morphometric analyses. The fruits from individuals grown under the cultivation system were significantly different from the individuals who were managed in situ and from those under incipient management. The perception study showed that local people perceive great morphological diversity among the study populations, which was consistent with the findings of the morphometric analyses. Based on these results, it could be said that C. coriaceum is in the early stage of the domestication process.
Defence responses in rice plants in prior and simultaneous applications of Cladosporium sp. during leaf blast suppression
(2016) Chaibub, Amanda Abdallah; Carvalho, Jacqueline Campos Borba de; Silva, Carlos de Sousa; Collevatti, Rosane Garcia; Goncalves, Fabio José; Cortes, Márcio Vinícius de Carvalho Barros; Filippi, Marta Cristina Corsi de; Faria, Fabrícia Paula de; Lopes, Douglas Christian Borges; Araújo, Leila Garcês de
An alternative method to control rice blast (Magnaporthe oryzae) is to include biological agent in the disease management strategy. The objective of this study was to assess the leaf blast-suppressing effects of rice phylloplane fungi. One Cladosporium sp. phylloplane fungus was shown to possess biocontrolling traits based on its morphological characteristics and an analysis of its 18S ribosomal DNA. Experiments aimed at determining the optimal time to apply the bioagent and the mechanisms involved in its rice blast-suppressing activities were performed under controlled greenhouse conditions. We used foliar spraying to apply the Cladosporium sp. 48 h prior to applying the pathogen, and we found that this increased the enzymatic activity. Furthermore, in vitro tests performed using isolate C24 showed that it possessed the ability to secrete endoxylanases and endoglucanases. When Cladosporium sp. was applied either prior to or simultaneous with the pathogen, we observed a significant increase in defence enzyme activity, and rice blast was suppressed by 84.0 and 78.6 %, respectively. However, some enzymes showed higher activity at 24 h while others did so at 48 h after the challenge inoculation. Cladosporium sp. is a biological agent that is capable of suppressing rice leaf blast by activating biochemical defence mechanisms in rice plants. It is highly adapted to natural field conditions and should be included in further studies aimed at developing strategies to support ecologically sustainable disease management and reduce environmental pollution by the judicious use of fungicidal sprays.

Navegar

Submissões Recentes