História evolutiva de Manihot carthagenensis (Euphorbiaceae) e espécies afins no leste da América do Sul

Manihot Mill. (Euphorbiaceae) is a Neotropical genus with approximately 100 species. Manihot carthagenensis is a very polymorphic species and associated with dry environments, mostly the caatinga and the chaco. Currently, morphological criteria associated with geographic distribution distinguish three infraspecific taxa in M. carthagenensis: M. carthagenensis subsp. carthagenensis, M. carthagenensis subsp. glaziovii, and M. carthagenensis subsp. hahnii. Herein, we assembled multilocus datasets with DNA sequence data obtained from four nuclear genes (sts, ch_metE, g3pdh, and nia-i3) for 34 samples of the three subspecies of M. carthagenensis and 14 samples from 10 closely-related species and carried out Bayesian phylogenetic analyses. We also obtained microsatellite data from 19 representative populations sampled throughout most of the known range of M. carthagenensis to investigate genetic structure and diversity. Our phylogenetic study suggested that M. carthagenensis, as presently circumscribed, does not constitute a monophyletic clade, but represents three well-differentiated lineages: M. carthagenensis, M. glaziovii and M. hahnii. These three lineages were supported based on morphological differences, genealogical relationships, and vegetation associations. Microsatellite data suggest that M. carthagenensis consists of at least three distinct gene pools partly structured according to geography. We hyphothesized that these gene pools evolved in allopatry but remained interfertile and were able to produce hybrid zones after reconnecting. Thereby the genetic admixture is of recent origin and owing to population expansion.Manihot Mill. (Euphorbiaceae) é um gênero Neotropical com aproximadamente 100 espécies. Manihot carthagenensis é uma espécie muito polimórfica e associada com ambientes secos, principalmente a caatinga e o chaco. Atualmente, critérios morfológicos associados com distribuição geográfica distingue três táxons infraespecíficos em M. carthagenensis: M. carthagenensis subsp. carthagenensis, M. carthagenensis subsp. glaziovii, and M. carthagenensis subsp. hahnii. Reunimos conjuntos de dados multilocus com dados de sequências de DNA obtidos de quatro genes nucleares (sts, ch_metE, g3pdh, and nia-i3) para 34 amostras das três subespécies de M. carthagenensis e 14 amostras de 10 espécies relacionadas e realizamos análise filogenética Bayesiana. Também obtivemos dados de microssatélites para 19 populações representativas amostradas ao longo da maior parte da extensão conhecida de M. carthagenensis, para investigar a estrutura genética e diversidade. Nosso estudo filogenético sugeriu que M. carthagenensis, como atualmente circunscrita, não constitui um clado monofilético mas representa três linhagens bem diferenciadas: M. carthagenensis, M. glaziovii e M. hahnii. Essas três linhagens foram apoiadas com base em diferenças morfológicas, relações genealógicas e associação com a vegetação. Dados de microssatélites sugerem que M. carthagenensis consiste em pelo menos três pools gênicos distintos, parcialmente estruturados de acordo com a geografia. Hipotetizamos que esses pools gênicos evoluíram em alopatria mas permaneceram interférteis e foram capazes de produzir zonas híbridas após reconexão. Assim, a mistura genética generalizada que observamos é de origem recente e devido à expansão populacional.Conselho Nacional de Desenvolvimento Científico e Tecnológic

Genetic structure and diversity of genus Anadenanthera Speg. (Leguminosae – Mimosoideae) estimated with microsatellite markers

O gênero Anadenanthera (Leguminosae–Mimosoideae) está atualmente circunscrito como duas espécies com duas variedades cada uma de acordo com Altschul 1964: A. colubrina (Vell.) Brenan var. colubrina; A. colubrina var. cebil (Griseb.) Altschul; A. peregrina (L.) Speg. var. peregrina; e A. peregrina var. falcata (Benthan) Altschul, mas já foram consideradas como quatro espécies distintas segundo a classificação de Brenan 1955: A. colubrina (Vell.) Brenan, A. macrocarpa (Benth.) Brenan, A. peregrina (L.) Speg. e A. falcata (Benth.) Speg. Espécies de Anadenanthera Speg. ocorrem na maioria dos núcleos disjuntos das florestas estacionais, sendo a espécie A. colubrina var. cebil (Griseb.) Altschul mais amplamente distribuída nessas áreas e, por isso, considerada como espécie modelo para estudo da história evolutiva dessas florestas. O objetivo desse estudo foi caracterizar a diversidade genética de espécies do gênero Anadenanthera Speg. Doze marcadores microssatélites foram utilizados para genotipar 283 espécimes. Os resultados de três análises (STRUCTURE, NJ e PCoA) foram concordantes e mostraram claramente quatro grupos genéticos para o gênero Anadenanthera. A diferenciação de A. colubrina foi observada com microssatélites e ITS, mostrando congruência parcial entre os resultados desses marcadores. A diversidade genética em termos de riqueza alélica e heterozigosidade mostraram valores mais elevados e similares nas espécies A. macrocarpa, A. peregrina e A. falcata em comparação ao valor particularmente baixo encontrado para a espécie A. colubrina. Análises de pares de FST e número médio de migrantes entre populações de cada espécie sensu Altschul 1964 mostraram fluxo gênico restrito entre variedades. A diversificação de A. colubrina foi provavelmente anterior à diversificação das demais espécies. A baixa diversidade em A. colubrina foi possivelmente consequência da sua distribuição mais restrita e da elevada endogamia. A miscigenação das populações de A. falcata refletiu um cenário de expansão recente para essa espécie. Os resultados sugerem que a circunscrição das espécies de Anadenanthera proposta por Brenan é a mais adequada.The Anadenanthera genus (Leguminosae - Mimosoideae) is currently circumscribed into two species with two varieties each according to Altschul 1964: A. colubrina (Vell.) Brenan var. colubrina; A. colubrina var. cebil (Griseb.) Altschul; A. peregrina (L.) Speg. var. peregrina; and A. peregrina var. falcata (Bentham) Altschul. However, they were already considered as four distinct species according to the classification of Brenan 1955: A. colubrina (Vell.) Brenan, A. macrocarpa (Benth.) Brenan, A. peregrina (L.) Speg. e A. falcata (Benth.) Speg. The Anadenanthera Speg. species occur in most of seasonal forests disjunct nucleus. The specie A. colubrina var. cebil (Griseb.) Altschul is more widely distributed in these areas and therefore considered as a model species for studying the evolutionary history of the seasonal forests. The aim of this study was to characterize the genetic diversity of the genus Anadenanthera Speg. Twelve microsatellite markers were used to genotype 283 specimens. The results of three analyzes (STRUCTURE, NJ and PCoA) were concordant and showed clearly four genetic groups in the Anadenanthera genus. The differentiation of A. colubrina was observed with microsatellites and ITS and showed partial congruence between the results of these markers. The genetic diversity under allelic richness and heterozygosity showed higher and similar values in the species A. macrocarpa, A. peregrina and A. falcata, compared to the lowest values found for the species A. colubrina. Analyzes of pairs of FST and mean number of migrants between populations of each species sensu Altschul 1964 showed restricted gene flow between varieties. The diversification of A. colubrina was probably before the diversification of other species. The low diversity in A. colubrina was possibly a consequence of its more restricted distribution and high inbreeding. The admixure of populations of A. falcata reflected a scenario of recent expansion of this species. The results suggest that the division of the species of Anadenanthera proposed by Brenan is the most suitable.Conselho Nacional de Desenvolvimento Científico e Tecnológic

Evolutionary history of Manihot carthagenensis (Euphorbiaceae) and allied species in eastern South America

Intermittent episodes of climate changes, such as those that occurred during the Pleistocene, likely shaped the diversification of the young genus Manihot Mill. (Euphorbiacheae). One of such recently-derived congeners ─ M. carthagenensis ─ exhibits a widely disjunct distribution across dry environments in Eastern South America. Herein, we used molecular data from four nuclear gene regions (sts, ch_metE, g3pdh, and nia-i3) and seven nuclear microsatellite loci for reconstructing the phylogenetic relationships among M. carthagenensis and allied species and exploring likely phylogeographic scenarios that shaped the diversification and the distribution of gene pools of M. carthagenensis across the Caatinga and Chaco. Our data suggest that M. carthagenensis is not a monophyletic clade, as presently circumscribed. Morphological differences, genealogical relationships, and vegetation associations support three well-differentiated lineages, each of which merits the species rank: M. carthagenensis, M. glaziovii, and M. hahnii. Microsatellite data suggest that the newly circumscribed M. carthagenensis consists of at least three distinct gene pools, which are partly structured according to geography. The three gene pools likely evolved in allopatry, but remained interfertile. Population expansions after climate amelioration contributed to structuring hybrid zones. Moreover, we described two new single-copy gene regions (sts and ch_metE) as sources of molecular variation; they can facilitate the fine-scale probing of other parts of the phylogeny across Manihot

Brazilian Flora 2020: Leveraging the power of a collaborative scientific network

International audienceThe shortage of reliable primary taxonomic data limits the description of biological taxa and the understanding of biodiversity patterns and processes, complicating biogeographical, ecological, and evolutionary studies. This deficit creates a significant taxonomic impediment to biodiversity research and conservation planning. The taxonomic impediment and the biodiversity crisis are widely recognized, highlighting the urgent need for reliable taxonomic data. Over the past decade, numerous countries worldwide have devoted considerable effort to Target 1 of the Global Strategy for Plant Conservation (GSPC), which called for the preparation of a working list of all known plant species by 2010 and an online world Flora by 2020. Brazil is a megadiverse country, home to more of the world's known plant species than any other country. Despite that, Flora Brasiliensis, concluded in 1906, was the last comprehensive treatment of the Brazilian flora. The lack of accurate estimates of the number of species of algae, fungi, and plants occurring in Brazil contributes to the prevailing taxonomic impediment and delays progress towards the GSPC targets. Over the past 12 years, a legion of taxonomists motivated to meet Target 1 of the GSPC, worked together to gather and integrate knowledge on the algal, plant, and fungal diversity of Brazil. Overall, a team of about 980 taxonomists joined efforts in a highly collaborative project that used cybertaxonomy to prepare an updated Flora of Brazil, showing the power of scientific collaboration to reach ambitious goals. This paper presents an overview of the Brazilian Flora 2020 and provides taxonomic and spatial updates on the algae, fungi, and plants found in one of the world's most biodiverse countries. We further identify collection gaps and summarize future goals that extend beyond 2020. Our results show that Brazil is home to 46,975 native species of algae, fungi, and plants, of which 19,669 are endemic to the country. The data compiled to date suggests that the Atlantic Rainforest might be the most diverse Brazilian domain for all plant groups except gymnosperms, which are most diverse in the Amazon. However, scientific knowledge of Brazilian diversity is still unequally distributed, with the Atlantic Rainforest and the Cerrado being the most intensively sampled and studied biomes in the country. In times of “scientific reductionism”, with botanical and mycological sciences suffering pervasive depreciation in recent decades, the first online Flora of Brazil 2020 significantly enhanced the quality and quantity of taxonomic data available for algae, fungi, and plants from Brazil. This project also made all the information freely available online, providing a firm foundation for future research and for the management, conservation, and sustainable use of the Brazilian funga and flora