RESUMO
A complete chloroplast genome is not yet available for numerous species of plants. Among the groups that lack plastome information is the clusioid clade (Malpighiales), which includes five families: Bonnetiaceae, Calophyllaceae, Clusiaceae, Hypericaceae, and Podostemaceae. With around 2200 species, it has few published plastomes and most of them are from Podostemaceae. Here we assembled and compared six plastomes from members of the clusioids: five from Calophyllaceae (newly sequenced) and one from Clusiaceae. Putative regions for evolutionary studies were identified and the newly assembled chloroplasts were analyzed with other available chloroplasts for the group, focusing on Calophyllaceae. Our results mostly agree with recent studies which found a general conserved structure, except for the two Podostemaceae species that have a large inversion (trnK-UUU-rbcL) and lack one intron from ycf3. Within Calophyllaceae we observed a longer LSC and reduced IRs in Mahurea exstipulata, resulting in some genic rearrangement, and a short inversion (psbJ-psbE) in Kielmeyera coriacea. Phylogenetic analyses recovered the clusioids and the five families as monophyletic and revealed that conflicts in relationships reported in the literature for the group agree with nodes concentrating uninformative or conflicting gene trees. Our study brings new insights about clusioid plastome architecture and its evolution.
Assuntos
Clusiaceae/genética , Malpighiales/genética , Cloroplastos/genética , Evolução Molecular , Genoma de Cloroplastos/genética , Íntrons/genética , Magnoliopsida/genética , Filogenia , Análise de Sequência de DNA/métodosRESUMO
Platonia insignis is a fruit tree native of Brazil with allogamous and asexual reproduction. The production of fruits is mainly obtained by exploitation of natural populations and the impact of genetic structuring on plant production may be evaluated. For this purpose, codominant and multiallelic markers such as microsatellite are the most suitable, but they need to be developed for this species. Thus, the aim of this work was to develop and validate microsatellite markers for P. insignis. We used Roche 454 GS FLX sequencing platform of a single P. insignis genotype and 1702 microsatellite sequences were identified. Based on some pre-requisites, we could develop 50 primer pairs to be tested. Twenty-two primer pairs successfully amplified fragments and they were tested in 31 genotypes of P. insignis that belong to a germplasm bank and were sampled in the northeast of Pará State, Brazil. Thirteen primers were polymorphic and the number of alleles per loci varied from 5 (PI18 and PI27) to 2 (PI08, PI25, PI31, PI33 and PI 37). Expected heterozygosity (HE) varied from 0.74 (PI27) to 0.12 (PI31) and observed heterozygosity (HO) varied from 1.00 (PI25) to 0.00 (PI08, PI31, PI33 and PI37). Principal coordinates could separate the genotypes of P. insignis in clusters and we can conclude that the primers can estimate the genetic diversity of P. insignis populations.
Assuntos
Clusiaceae/genética , Repetições de Microssatélites/genética , Alelos , Brasil , Primers do DNA/genética , DNA de Plantas/genética , Frutas/genética , Genômica/métodos , Genótipo , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Polimorfismo Genético/genética , Árvores/genéticaRESUMO
Population genetic studies in tropical plants are often challenging because of limited information on taxonomy, phylogenetic relationships and distribution ranges, scarce genomic information and logistic challenges in sampling. We describe a strategy to develop robust and widely applicable genetic markers based on a modest development of genomic resources in the ancient tropical tree species Symphonia globulifera L.f. (Clusiaceae), a keystone species in African and Neotropical rainforests. We provide the first low-coverage (11X) fragmented draft genome sequenced on an individual from Cameroon, covering 1.027 Gbp or 67.5% of the estimated genome size. Annotation of 565 scaffolds (7.57 Mbp) resulted in the prediction of 1046 putative genes (231 of them containing a complete open reading frame) and 1523 exact simple sequence repeats (SSRs, microsatellites). Aligning a published transcriptome of a French Guiana population against this draft genome produced 923 high-quality single nucleotide polymorphisms. We also preselected genic SSRs in silico that were conserved and polymorphic across a wide geographical range, thus reducing marker development tests on rare DNA samples. Of 23 SSRs tested, 19 amplified and 18 were successfully genotyped in four S. globulifera populations from South America (Brazil and French Guiana) and Africa (Cameroon and São Tomé island, FST = 0.34). Most loci showed only population-specific deviations from Hardy-Weinberg proportions, pointing to local population effects (e.g. null alleles). The described genomic resources are valuable for evolutionary studies in Symphonia and for comparative studies in plants. The methods are especially interesting for widespread tropical or endangered taxa with limited DNA availability.
Assuntos
Clusiaceae/genética , Genoma de Planta , Repetições de Microssatélites , Filogenia , Polimorfismo de Nucleotídeo Único , Brasil , Camarões , Guiana Francesa , Marcadores Genéticos , Genética PopulacionalRESUMO
Abstract We investigated the composition and structure of fungal communities associated with leaf litter generated by Clusia nemorosa and Vismia guianensis that belong to phylogenetically-related botanical families and exist together in a remnant of the Atlantic Forest in Bahia, Brazil. Samplings were conducted during wet (June 2011) and dry (January 2013) seasons in Serra da Jibóia. The fungi were isolated using particle filtration and the 1,832 isolates represented 92 taxa. The wet season yielded the largest number of isolates (1,141) and taxa (76) compared with the dry season (641 isolates and 37 taxa). The richness and diversity of fungal species associated with C. nemorosa (64 taxa, Simpson=0.95)were higher compared with those of V.guianensis (59 taxa, Simpson =0.90). Analysis of similarity (ANOSIM) revealed significant variations in the composition and community structure of fungi isolated from the two plants as a function of seasons. In contrast, nonmetric multidimensional scaling (NMDS) analysis show that the seasonality was an important influence on the distribution of fungal species. However, the populations of the saprobic fungal communities were dynamic, and several factors may influence such communities in the Atlantic Forest.
Assuntos
Brasil/classificação , Brasil/genética , Brasil/isolamento & purificação , Brasil/microbiologia , Clusia/classificação , Clusia/genética , Clusia/isolamento & purificação , Clusia/microbiologia , Clusiaceae/classificação , Clusiaceae/genética , Clusiaceae/isolamento & purificação , Clusiaceae/microbiologia , Ecossistema/classificação , Ecossistema/genética , Ecossistema/isolamento & purificação , Ecossistema/microbiologia , Florestas/classificação , Florestas/genética , Florestas/isolamento & purificação , Florestas/microbiologia , Fungos/classificação , Fungos/genética , Fungos/isolamento & purificação , Fungos/microbiologia , Folhas de Planta/classificação , Folhas de Planta/genética , Folhas de Planta/isolamento & purificação , Folhas de Planta/microbiologia , Estações do Ano/classificação , Estações do Ano/genética , Estações do Ano/isolamento & purificação , Estações do Ano/microbiologia , Árvores/classificação , Árvores/genética , Árvores/isolamento & purificação , Árvores/microbiologiaRESUMO
The broad geographic range of many Neotropical rain forest tree species implies excellent dispersal abilities or range establishment that preceded the formation of current dispersal barriers. In order to initiate historical analyses of such widespread Neotropical trees, we sequenced the nuclear ribosomal spacer (ITS) region of Symphonia globulifera L. f. (Clusiaceae) from populations spanning the Neotropics and western Africa. This rain forest tree has left unmistakable Miocene fossils in Mesoamerica (15.5-18.2 Ma) and in South America ( approximately 15 Ma). Although marine dispersal of S. globulifera is considered improbable, our study establishes three marine dispersal events leading to the colonization of Mesoamerica, the Amazon basin, and the West Indies, thus supporting the paleontological data. Our phylogeographic analysis revealed the spatial extent of the three Neotropical S. globulifera clades, which represent trans-Andes (Mesoamerica+west Ecuador), cis-Andes (Amazonia+Guiana), and the West Indies. Strong phylogeographic structure found among trans-Andean populations of S. globulifera stands in contrast to an absence of ITS nucleotide variation across the Amazon basin and indicates profound regional differences in the demographic history of this rain forest tree. Drawing from these results, we provide a historical biogeographic hypothesis to account for differences in the patterns of beta diversity within Mesoamerican and Amazonian forests.