Abstract
The understanding of genetic diversity and evolutionary relationships within the genus Anadenanthera Speg. (Fabaceae) is limited. Brenan’s classification recognized four species, but ...Altschul’s classification currently recognizes only two species, each with two varieties. Both classifications were based solely on morphology. We analysed molecular data from 283 specimens using 12 SSRs and 186 specimens using ITS sequence data. The results showed that neither SSR-based genotyping nor ITS-based phylogeny supported Altschul’s classification. Instead, they provided evidence of four reproductively isolated taxa and a single clade corresponding to one of Altschul’s varieties. Additionally, ecological niche modelling (ENM) investigated the influence of past climate on the geographic distribution of Anadenanthera. The ENM results suggest that the ‘varieties’ may have occupied different regions of South America with distinct paleoclimates. On the basis of these findings, the authors suggest recognizing four species, as per Brenan’s original classification.
The genus Tulasnella often forms mycorrhizas with orchids and has worldwide distribution. Species of this genus are associated with a wide range of orchids, including endangered hosts. Initially, ...species identification relied mostly on morphological features and few cultures were preserved for later phylogenetic comparisons. In this study, a total of 50 Tulasnella isolates were collected from their natural sites in Minas Gerais, Brazil, cultured, and subjected to a phylogenetic analysis based on alignments of sequences of the internal transcribed spacer (ITS) of the nuclear ribosomal DNA. Our results, based on phylogeny, integrated with nucleotide divergence and morphology, revealed the diversity of isolated Tulasnella species, which included four new species, namely, Tulasnella brigadeiroensis, Tulasnella hadrolaeliae, Tulasnella orchidis and Tulasnella zygopetali. The conservation of these species is important due to their association with endangered orchid hosts and endemic features in the Brazilian Atlantic Forest.
Quaternary climatic fluctuations have shaped the geographic distribution of lineages, potentially affecting the demography, genetic structure, and patterns of genetic diversity of extant species. ...Different phylogeographic scenarios have been proposed for plants in neotropical cloud forests during the Last Glacial Maximum based on paleoecological data: the dry refugia hypothesis (DRH) and the moist forest hypothesis. We specifically focus on the Brazilian Atlantic Forest (BAF) range of Cedrela fissilis (Meliaceae), sampling 410 specimens from 50 localities. Our study combines analyses of the genetic diversity, phylogeographic patterns, and past geographic distributions with a particular focus on highland populations. We identified 283 alleles across the 11 microsatellite loci, ranging from 18 to 33 alleles per locus, distributed across five genetic groups. Most populations of C. fissilis from the BAF exhibited a diffuse genetic structure, reflected in low pairwise FST values, which could be the consequence of high gene flow. In addition, the plastid data showed a connection between the western, southern, and eastern populations in the North‐East of Brazil, but no association between genetic data and elevation was observed. Habitat suitability projections over the past 140 000 years showed less fragmentation relative to the present, indicating a higher connectivity and gene flow. Our results provide support for both the moist forest as well as the DRH, suggesting that most likely, a mixture of these processes has acted through space and time.
PREMISE OF THE STUDY: We investigated how genetic diversity is distributed across the range of Cedrela fissilis, a tree species associated with seasonal neotropical forests, to gain insights into ...competing biogeographic scenarios that explain how disjunct distributions of these forests were shaped. METHODS: A total of 250 samples were sampled from 18 sites across the species' range in Brazil and eastern Bolivia and genotyped with 10 microsatellite loci. An array of complementary methods—F statistics, analyses of molecular variance (AMOVA), and clustering analyses—assessed genetic diversity, population differentiation, and structure. KEY RESULTS: Most of the genetic diversity (82.5%) was partitioned within populations, but about 12% was due to differences among groups of populations on either side of the Cerrado or located within the Cerrado; mean expected heterozygosity and mean observed heterozygosity were 0.821 and 0.704, respectively. The 250 samples were sorted into two Bayesian groups: one group for each side of the Cerrado. The populations showed varying levels of admixture, with the greatest admixture evident in populations located toward central Brazil. CONCLUSIONS: In C. fissilis, genetic diversity is structured according to geography: the Atlantic range and the Chiquitano range each harbor a genealogical lineage. InterfertiUty and varying levels of admixture between lineages provide strong evidence that the lineages evolved under geographic, but not genetic, isolation. Admixture is of recent origin, owing to population expansion. Cedrela fissilis shares this dual pattern of distribution of genetic diversity with other phylogenetically unrelated taxa that are typically associated with seasonal forests.
ABSTRACT Many tropical trees have high canopies and their leaves are not accessible. Thus, the use of tissue from a more accessible organ (cambium) for DNA extraction may be an alternative for ...molecular studies. We adapted a feasible methodology for extracting genomic DNA from cambium tissue harvested in the field for the assessment with PCR. We tested three storage conditions (two buffers and a silica gel) and four periods of time after harvest. We used previously described protocols and tested them on three species that occur in Amazonian forests and other biomes: Anadenanthera peregrina var. peregrina, Cedrela fissilis, and Ceiba speciosa. Our protocol obtained suitable PCR-grade genomic DNA for DNA sequencing and microsatellite genotyping. We recommend the use of silica for long-term storage and the buffer with ascorbic acid for short-term storage.
RESUMO Muitas árvores tropicais possuem dossel alto e folhas não facilmente acessíveis. O uso de tecido de um órgão mais acessível (câmbio) para extração de DNA pode ser uma alternativa para estudos moleculares. Nós adaptamos uma metodologia viável para extrair DNA genômico de tecido cambial coletado no campo para avaliação com PCR. Testamos três condições de armazenamento (dois tampões e sílica gel) e quatro períodos após a coleta. Utilizamos protocolos descritos anteriormente e os testamos em três espécies encontradas em florestas amazônicas e outros biomas: Anadenanthera peregrina var. peregrina, Cedrela fissilis e Ceiba speciosa. Nosso protocolo foi eficaz na obtenção de DNA adequado para sequenciamento e genotipagem de microssatélites. Recomendamos o uso de sílica para armazenamento de longo prazo e o tampão com ácido ascórbico para curto prazo.
ABSTRACT Soil microbiota is an important component of the forest biomes, playing important roles in the soil aggregation and cycling of nutrients. Among the soil microorganisms stand out the yeasts, ...which are unicellular fungi involved in important soil ecological processes. The Brazilian Atlantic Forest is one of the main biodiversity hotspots in the world, and the effect of altitudinal gradient on the distribution patterns of yeast species across this ecosystem has not yet been addressed. Thus, this study aimed to investigate the occurrence and distribution of yeast species in soils along an altitude gradient (404; 1,016; 1,658; and 2,124 m above the sea level) of Serra dos Órgãos National Park located at Rio de Janeiro State, Brazil. Yeast species were described using a culture-based method. Species identification was performed using the fungal barcode locus, the D1/D2 region of 26S rRNA, and the gene genealogy was used to access the intraspecific distribution of strains along the altitudinal gradient. We isolated and identified a total of 76 yeasts including ten species belonging to eight genera. Basidiomycetes predominated over ascomycetes. Saitozyma podzolica and Meyerozyma guilliermondii were isolated at all altitudes. The principal component analysis showed that 88 % of sample distribution is explained by soil properties. For S. podzolica, the genetic genealogy suggested that intraspecific distribution is likely related to similar altitudes. Overall, the species composition and soil properties were modified as altitude was increasing, being more heterogeneous and richness in high altitudes.
Naturally rare species have a higher probability of stochastic extinction due to genetic, demographic, or environmental hazards; human disturbance may intensify these threats. Rare species may ...therefore be in need of short-term intervention to survive. The ecosystem with the second highest biodiversity in Brazil, the Cerrado, is suffering from fragmentation and threats to its flora.
Dimorphandra wilsonii
, a 30-m tall endemic tree of the Brazilian Cerrado, is listed as critically endangered; only 21 adult trees have been identified. We carried out mating system and pollen flow analyses to understand the current gene flow and limitations in the reproduction of
D. wilsonii
. With seven fluorescently labelled microsatellite primers, we genotyped 20 adult trees and 269 progeny from 13 mother trees.
D. wilsonii
displayed low levels of genetic diversity; bottleneck events are likely to have occurred (
H
e
= 0.60 and 0.29;
H
o
= 0.71 and 0.33, for adults and progeny, respectively). This species is predominantly outcrossing (
t
m
= 0.88), with some selfing (1-
t
m
= 0.12), as well as crossing between related individuals (
t
m
-
t
s
= 0.11). None of the studied trees was reproductively isolated; a high proportion of pollen (55 %) came from trees yet to be discovered. Two genetic clusters (Northern and Southern) were identified, with high values of genetic divergence among the Southern sites. Planting of seedlings and monitoring of seed dispersion in order to maintain the genetic diversity and genetic structure of
D. wilsonii
are strategies that may ensure the continuation of
D. wilsonii
, but this species does not seem to require reproductive intervention to remain viable.
Submitted by Reginaldo Soares de Freitas (reginaldo.freitas@ufv.br) on 2017-02-08T11:42:45Z;
No. of bitstreams: 1;
texto completo.pdf: 7141983 bytes, checksum: 6726b1c828edabd75d3397e5e4e2c6d3 (MD5)
...Made available in DSpace on 2017-02-08T11:42:45Z (GMT). No. of bitstreams: 1;
texto completo.pdf: 7141983 bytes, checksum: 6726b1c828edabd75d3397e5e4e2c6d3 (MD5);
Previous issue date: 2016-09-29
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
A floresta Atlântica brasileira, uma das regiões de maior biodiversidade no mundo, está entre as cinco áreas mais importantes, hotspot de biodiversidade, possuindo mais de 8.000 espécies endêmicas. Entretanto, ela é uma das florestas mais ameaçadas do mundo. Estudos vêm sendo conduzidos com o objetivo de tentar entender as razões que levaram a este grande acúmulo de biodiversidade. Nós estudamos o modelo de distribuição de espécies, diversidade genética e filogeografia em populações de Cedrela fissilis da floresta Atlântica, com o intuito de responder se populações estariam em refúgios secos ou em florestas úmidas durante o último máximo glacial (LGM). Nossos resultados mostraram suporte para ambas as hipóteses, sugerindo assim que provavelmente uma combinação de processos atuaram no espaço e no tempo formando a diversidade que existe atualmente. Além disso, Estudos moleculares necessitam de DNA de qualidade e, em plantas, as folhas não estão sempre disponíveis. Dessa forma, nós testamos uma completa metodologia de extração de tecido do câmbio em diferentes espécies (Anadenanthera peregrina var. peregrina, Cedrela fissilis, Ceiba speciosa e Dimorphandra wilsonii) a fim de obter um DNA adequado para amplificação. O protocolo utilizado aqui, desde a coleta até a extração, foi efetivo para a obtenção de produtos de PCR para sequenciamento e genotipagem.
The Brazilian Atlantic forest, one of the most biodiverse regions in the world, is among the five most important areas, biodiversity hotspot, harbouring more than 8,000 endemic species. However, it exhibits the most threatened forests in the world. Studies have been conducted in order to understand the reasons that led to this high accumulation of biodiversity. We evaluated species distribution model, genetic diversity and phylogeography of populations of Cedrela fissilis from Atlantic range, in order to answer whether populations were in dry refugia or in moist forests during the last glacial maximum (LGM). Our results showed support for both hypotheses, suggesting that likely a mixture of processes have acted through space and time. In addition to this study, molecular studies require DNA isolated, and in plants the leaves are not always available. Thus, we also tested a complete methodology of DNA extraction from cambium tissue in different species (Anadenanthera peregrina var. Peregrina, Cedrela fissilis, Ceiba speciosa and Dimorphandra wilsonii) in order to obtain a suitable DNA for amplification. The protocol used here, showed from the collected steps until extraction, was effective for obtaining PCR products for sequencing and genotyping.
Made available in DSpace on 2015-03-26T13:42:27Z (GMT). No. of bitstreams: 1
texto completo.pdf: 1342445 bytes, checksum: 3173736fe2ef2bd06f0426301a5db782 (MD5)
Previous issue date: 2012-09-05
...Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
The knowledge of how genetic variation is partitioned among populations may have important implications in evolutionary, ecology and conservation biology. The Cedrela fissilis species (Meliaceae) is a tree associated with Seasonal and Moist Forest. In addition, this species is considered "endangered" on the red list of the IUCN due to the loss of habitat and its high timber value. C. fissilis is formed by two phylogenetic lineages that are not a monophyletic clade, comprising sequences of C. odorata and C. balansae, called C. fissilis complex. The aim of this study was to characterize the genetic diversity of C. fissilis complex intra and inter populations in Brazil and Bolivia. Eight microsatellites were used to genotype 245 individuals, then it was obtained high values of heterozygosity (HO=0.73, HE=0.81), with positive values of FIS (FIS=0.11), indicating excess of homozygotes. For AMOVA, 94.39% of the variation were within populations and 5.61% were among populations which also reflected low levels of genetic divergence (FST=0.075). The populations of the Atlantic range showed slightly more diverse, with 20 of 37 private alleles found. It presented FST value (FST=0.063) greater than the populations of Amazonic-Chiquitano range (FST=0.022). It has been found weak populations structure showing a number of groups equal to eight and being greater than the number of known phylogenetic lineages based on DNA sequences. The low interpopulation differences found suggest the same mechanisms for conservation management. Furthermore, some populations showed conservation relevance due to the presence of peculiar genetic material and characteristics of refuge.
O conhecimento de como a variação genética está dividida nas populações pode ter implicações importantes na biologia evolutiva, ecológica e na conservação. A espécie Cedrela fissilis (Meliaceae) é uma espécie arbórea associada à Floresta Estacional e Ombrófila. Além disso, esta espécie é considerada ameaçada na lista vermelha de espécies da IUCN devido à perda de habitat e ao alto valor econômico da sua madeira. C. fissilis é formada por duas linhagens genealógicas não monofiléticas, compreendendo sequências de C. odorata e C. balansae e, portanto, denominadas de complexo C. fissilis. O objetivo geral deste trabalho foi caracterizar a diversidade genética intra e interpopulacional do complexo C. fissilis no Brasil e Bolívia. Oito microssatélites foram utilizados para genotipar 245 indivíduos e foram obtidos elevados valores de heterozigosidades (HO=0,73; HE=0,81), com valores de FIS positivos (FIS=0,11), indicando excesso de homozigotos. Para AMOVA, 94,39% da variação foram dentro de populações e 5,61% entre populações e que também refletiu em baixos valores de divergência genética (FST=0,075). As populações da área de distribuição do Atlântico se mostraram ligeiramente mais diversificadas, com 20 dos 37 alelos privados encontrados e apresentaram valor de FST (FST=0,063) maior que as populações do AC (FST=0,022). Foi constatada fraca estruturação das populações, exibindo um número de grupos igual a oito, sendo maior que o número de linhagens conhecidas, com base em sequências de DNA. A baixa diferença interpopulacional encontrada sugere iguais mecanismos de manejo para conservação. Além disso, algumas populações apresentaram relevância de conservação devido à presença de material genético peculiar e às características de refúgio.
PDF
