Reofitismo : desde a taxonomia aos mecanismos regulatórios

Reófitas constituem um grupo biológico de plantas tolerantes a inundação que na natureza são confinadas a leitos de rios e córregos de água corrente e são submetidas a inundações periódicas ao longo do ano. O reofitismo está presente tanto em plantas avasculares (hepáticas, antóceros e musgos), quanto em plantas vasculares (pteridófitas, licófitas, gimnospermas e angiospermas). O livro Rheophytes of the world, juntamente com o seu complemento, publicados em 1981 e 1987, respectivamente, constituem as referências mundiais sobre o reofitismo em plantas. Embora mais de 35 anos tenham-se passado desde da publicação do primeiro censo de reófitas, nenhum pesquisador atualizou o número de táxons desse grupo biológico em plantas com sementes e/ou compilou dados sobre essas espécies a partir da literatura. Além disso, havia falta de uma caracterização morfológica, bioquímica, e molecular em resposta a inundação em espécies reófitas na literatura publicada. No primeiro artigo dessa tese (Capítulo II), revisamos os principais tópicos associados ao reofitismo, incluindo características morfológicas, estudos genéticos, distribuição geográfica, conservação e aspectos evolutivos. Além disso, atualizamos o checklist global de reófitas, considerando os dois grupos de plantas com semente (gimnospermas e angiospermas). E por fim, demonstramos a distribuição do reofitismo na filogenia das angiospermas e estimamos a distribuição geográfica e a riqueza de táxons selecionados no mapa mundial pela primeira vez. Compilamos um conjunto de dados composto por 1368 táxons (incluindo reófitas obrigatórias, facultativas e não classificadas) distribuídos em 114 famílias e 508 gêneros em angiospermas e quatro táxons em gimnospermas (família Podocarpaceae). Das 114 famílias plotadas na filogenia das angiospermas, pelo menos 80 possuem reófitas obrigatórias. A distribuição geográfica das reófitas em plantas com flores, conforme o esperado com base no primeiro censo desse grupo biológico, está principalmente localizada nas regiões tropicais e subtropicais. Uma alta riqueza de táxons reofíticos foi encontrada principalmente no sul do México, sul da China, Ilha do Bornéu e norte e leste da Austrália. Em contraste, a distribuição geográfica de reófitas em gimnospermas está restrita à Nova Caledônia e à Tasmânia. No segundo artigo dessa tese (Capítulo III), caracterizamos aspectos morfológicos, bioquímicos e expressão gênica de Dyckia brevifolia, uma reófita ameaçada de extinção e nativa do Brasil. Plântulas dessa bromélia foram expostas a submersão completa e recuperação em dois intervalos de tempo: um estresse curto (10 dias de submersão completa com 5 dias de recuperação), e um estresse longo (30 dias de submersão completa com 15 dias de recuperação). Dyckia brevifolia demonstrou ter adaptações importantes à tolerância à inundação, que incluem estratégia quiescente que restringe o cresci mento debaixo d’água, conservação do conteúdo de clorofilas, carotenóides e proteínas durante a submersão, restrição do catabolismo de carboidratos (principalmente amido) e um eficiente sistema de desintoxicação de espécies reativas de oxigênio (ROS), principalmente para o peróxido de hidrogênio (H2O2) quando completamente submersa. Durante o período de recuperação após a reexposição à atmosfera, a espécie também exibe características adaptativas importantes, como manutenção da turgidez das rosetas, retomada do crescimento rápido, recuperação total de açúcares solúveis, aumento do conteúdo de clorofilas e carotenóides e capacidade ativa de mitigar ROS nos primeiros quinze dias após a reoxigenação. Tomados em conjunto, esses resultados demonstram que as plântulas dessa bromélia apresentam importantes adaptações ao estresse de inundação e são bem adaptadas ao ambiente reofítico.The term rheophyte describes a biological group of flood-tolerant plants confined to the beds of swift-running streams and rivers in nature and grow up to flood-level, but not beyond the reach of regularly occurring flash floods. Rheophytism occurs in non-vascular (liverworts, hornworts, and mosses) and vascular plants (ferns, lycophytes, gymnosperms, and angiosperms). The book Rheophytes of the world, together with its complement, published in 1981 and 1987, respectively, constitute the world references on rheophytism in plants. Although more than 35 years have passed since the publication of the first census of rheophytes, no researcher has attempted to update the number of taxa of this biological group in seed plants and/or have tried to compile data about these species from literature. Additionally, the published literature showed a lack of a morphological, biochemical, and molecular characterization in response to flooding in rheophytic species. In the first article of this thesis (Chapter II), we review the main topics associated with rheophytism, including morphological characteristics, genetic studies, geographic distribution, conservation, and evolutionary aspects. In addition, we updated the global rheophyte checklist, considering the two groups of seed plants (gymnosperms and angiosperms). Finally, we demonstrate the distribution of rheophytism in the angiosperms phylogeny and estimated the geographic distribution and richness of selected taxa on the world map for the first time. We compiled a dataset composed of 1,368 taxa (obligate, facultative, and unclassified rheophytes) distributed in 114 families and 508 genera in angiosperms and four taxa in gymnosperms (Podocarpaceae family). Of the 114 families plotted in the angiosperm phylogeny, at least 80 have obligate rheophytes. As expected, based on the first census of this biological group, the geographic distribution of rheophytes in flowering plants is mainly in the tropical and subtropical regions.The high richness of rheophytic taxa was primarily found in southern Mexico, southern China, Borneo, and northern and eastern Australia. In contrast, the geographic distribution of rheophytes in gymnosperms is restricted to New Caledonia and Tasmania. In the second article of this thesis (Chapter III), we characterize morphological, biochemical, and gene expression aspects of Dyckia brevifolia, an endangered rheophyte native to Brazil. Seedlings of this bromeliad were exposed to complete submergence and recovery in two-time frames: short-term submergence stress (10 days of complete submergence with five days of recovery) and long-term submergence stress (30 days of complete submergence with 15 days of recovery). Dyckia brevifolia has shown important adaptations to flooding tolerance, which include a quiescent strategy that consists of decreased shoot elongation underwater, conservation of chlorophyll, carotenoid and protein con tent during submergence, restriction of carbohydrate catabolism (mainly starch), and an efficient reactive oxygen species (ROS) detoxification system, mainly for hydrogen peroxide (H2O2) when completely submerged. During the recovery period after de-submergence, the species also displays key adaptive features, such as maintaining rosette turbidity, fast-growth resumption, total recovery of soluble sugars, increased chlorophyll and carotenoid content, and active capacity to mitigate ROS in the first fifteen days after reoxygenation. Taken together, these results demonstrate that the seedlings of this bromeliad show important adaptations to flooding stress and are well adapted to the rheophytic environment

Hibridização de três espécies de pétalas amarelas de Aechmea subgênero Ortgiesia (Bromeliaceae)

Aechmea é reconhecido como o maior e mais problemático gênero (taxonomicamente) dentro da subfamília Bromelioideae (Bromeliaceae), apresentado grande variabilidade morfológica, reprodutiva e vegetativa. Um recente estudo envolvendo as espécies de Aechmea subgênero Ortgiesia detectou um híbrido putativo entre Aechmea comata (Gaudich.) Baker e A. caudata Lindm. No mesmo estudo, A. comata e A. kertesziae Reitz demonstraram um compartilhamento de haplótipos plastidiais, o que pode ser devido à retenção de polimorfismo ancestral, à ocorrência de hibridação, ou mesmo ao fato dessas espécies serem um único taxa, já que a delimitação usando morfologia é desafiadora. Estas três espécies sobrepõem período de floração, compartilham um polinizador e são encontradas em simpatria (A. comata e A. caudata) (A. comata e A. kertesziae) na Ilha de Santa Catarina. Portanto, o objetivo deste estudo foi investigar a delimitação taxonômica e a hibridação entre essas três espécies. Para isso, foram utilizados dez marcadores de microssatélites nucleares (nuSSR) e seis plastidiais (cpSSR), dados morfológicos e ecológicos, bem como experimentos de polinização controlados. Foram amostrados 244 indivíduos pertencentes às três espécies, oriundos de quatro populações alopátricas e quatro populações simpátricas. As análises bayesianas indicaram que cada espécie apresenta um perfil genético distinto, embora híbridos tenham sido identificados pelas análises moleculares. Aechmea comata demonstrou a maior diversidade genética já relatada para bromélias. Os híbridos identificados pelas análises bayesianas não apresentaram morfologia intermediária, dificultando sua identificação na natureza. Os dados morfológicos e ecológicos apoiam os dados moleculares de que A. comata, A. caudata e A. kertesziae são entidades distintas. Aechmea kertesziae apresentou sobreposição de características morfológicas com A. comata e A. caudata, devido à grande variabilidade intraespecífica. A análise ecológica demonstrou que as três espécies têm diferentes preferências de microhabitat. Dados de cruzamentos artificiais confirmaram a compatibilidade reprodutiva de A. comata com A. caudata e A. kertesziae. É provável que um conjunto de barreiras pré-zigóticas, como isolamento fenológico e etológico, autocompatibilidade e talvez barreiras pós-zigóticas, como baixa viabilidade ou esterilidade dos híbridos (incompatibilidades pós-zigóticas de Bateson-Dobzhanky-Muller) estejam envolvidas na manutenção da integridade de A. comata, A. caudata e A. kertesziae.Aechmea is recognized as the largest and most problematic taxonomically genus within subfamily Bromelioideae (Bromeliaceae), presenting great morphological, reproductive and vegetative variability. A recent study involving species of Aechmea subgenus Ortgiesia detected a putative hybrid between Aechmea comata (Gaudich.) Baker and A. caudata Lindm. In the same study, A. comata and A. kertesziae Reitz showed plastid haplotype sharing, which could be due to retention of ancestral polymorphism, occurrence of hybridization or even due the fact that these species are the same taxa, as the delimitation using morphology is challenging. These three species overlap in flowering time, share one pollinator, and are found in simpatry (A. comata and A. caudata) (A. comata and A. kertesziae) in the Santa Catarina Island. Therefore, the objective of this study was to investigate the taxonomic delimitation and hybridization among these three species. To do so, we used ten nuclear (nuSSR) and six plastid (cpSSR) microsatellite markers, morphological and ecological data, as well as controlled pollination experiments. We sampled 244 individuals belonging to the three species from four allopatric populations and four sympatric populations. Bayesian analyses indicated that each species present a distinct genetic profile, although hybrids have been identified by molecular analyzes Aechmea comata has demonstrated the highest genetic diversity already reported for bromeliads. The hybrids identified by Structure analyses did not show intermediate morphology, making difficult their identification in nature. The morphological and ecological data support the molecular data that A. comata, A. caudata, and A. kertesziae are distinct entities. Aechmea kertesziae presents overlapping morphological features with A. comata and A. caudata, due to great intraspecific variability. Ecological analysis has demonstrated that the three species have different preferences of microhabitat. Artificial crosses data confirmed the reproductive compatibility between A. comata with A. caudata and with A. kertesziae. It is likely that a set of prezygotic barriers as phenological and ethological isolation, self-compatibility, and perhaps postzygotic barriers, as low viability or sterility of hybrids, postzygotic Bateson-Dobzhanky-Muller incompatibilities are involved in maintaining species integrity of A. comata, A. caudata, and A. kertesziae

Development, characterization, and transferability of SSR markers for Vriesea carinata (Bromeliaceae) based on RNA sequencing

Premise of the Study: Expressed sequence tag–simple sequence repeat (EST-SSR) markers were isolated for Vriesea carinata, an endemic bromeliad from the Brazilian Atlantic Forest. These SSR loci may be used to investigate the genetic diversity and population structure of this species and related bromeliads. Methods and Results: Based on the transcriptome data of V. carinata, 30 primer pairs were designed and selected for initial validation. Of these primer pairs, 16 generated suitable SSR loci in 69 individuals. The number of alleles per locus ranged from one to 13; the levels of observed and expected heterozygosity per locus ranged from 0.000 to 1.000 and from 0.000 to 0.935, respectively. All loci produced heterologous amplification. Transferability of the loci was tested in 15 species belonging to three Bromeliaceae subfamilies. Conclusions: The developed EST-SSR markers revealed polymorphism in the four studied populations and could be useful to investigate the genetic diversity of V. carinata and related species. The markers may also be suitable for novel gene annotation and discovery

ATLANTIC EPIPHYTES: a data set of vascular and non-vascular epiphyte plants and lichens from the Atlantic Forest

Epiphytes are hyper-diverse and one of the frequently undervalued life forms in plant surveys and biodiversity inventories. Epiphytes of the Atlantic Forest, one of the most endangered ecosystems in the world, have high endemism and radiated recently in the Pliocene. We aimed to (1) compile an extensive Atlantic Forest data set on vascular, non-vascular plants (including hemiepiphytes), and lichen epiphyte species occurrence and abundance; (2) describe the epiphyte distribution in the Atlantic Forest, in order to indicate future sampling efforts. Our work presents the first epiphyte data set with information on abundance and occurrence of epiphyte phorophyte species. All data compiled here come from three main sources provided by the authors: published sources (comprising peer-reviewed articles, books, and theses), unpublished data, and herbarium data. We compiled a data set composed of 2,095 species, from 89,270 holo/hemiepiphyte records, in the Atlantic Forest of Brazil, Argentina, Paraguay, and Uruguay, recorded from 1824 to early 2018. Most of the records were from qualitative data (occurrence only, 88%), well distributed throughout the Atlantic Forest. For quantitative records, the most common sampling method was individual trees (71%), followed by plot sampling (19%), and transect sampling (10%). Angiosperms (81%) were the most frequently registered group, and Bromeliaceae and Orchidaceae were the families with the greatest number of records (27,272 and 21,945, respectively). Ferns and Lycophytes presented fewer records than Angiosperms, and Polypodiaceae were the most recorded family, and more concentrated in the Southern and Southeastern regions. Data on non-vascular plants and lichens were scarce, with a few disjunct records concentrated in the Northeastern region of the Atlantic Forest. For all non-vascular plant records, Lejeuneaceae, a family of liverworts, was the most recorded family. We hope that our effort to organize scattered epiphyte data help advance the knowledge of epiphyte ecology, as well as our understanding of macroecological and biogeographical patterns in the Atlantic Forest. No copyright restrictions are associated with the data set. Please cite this Ecology Data Paper if the data are used in publication and teaching events. © 2019 The Authors. Ecology © 2019 The Ecological Society of Americ

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

NEOTROPICAL XENARTHRANS: a data set of occurrence of xenarthran species in the Neotropics

Xenarthrans—anteaters, sloths, and armadillos—have essential functions for ecosystem maintenance, such as insect control and nutrient cycling, playing key roles as ecosystem engineers. Because of habitat loss and fragmentation, hunting pressure, and conflicts with domestic dogs, these species have been threatened locally, regionally, or even across their full distribution ranges. The Neotropics harbor 21 species of armadillos, 10 anteaters, and 6 sloths. Our data set includes the families Chlamyphoridae (13), Dasypodidae (7), Myrmecophagidae (3), Bradypodidae (4), and Megalonychidae (2). We have no occurrence data on Dasypus pilosus (Dasypodidae). Regarding Cyclopedidae, until recently, only one species was recognized, but new genetic studies have revealed that the group is represented by seven species. In this data paper, we compiled a total of 42,528 records of 31 species, represented by occurrence and quantitative data, totaling 24,847 unique georeferenced records. The geographic range is from the southern United States, Mexico, and Caribbean countries at the northern portion of the Neotropics, to the austral distribution in Argentina, Paraguay, Chile, and Uruguay. Regarding anteaters, Myrmecophaga tridactyla has the most records (n = 5,941), and Cyclopes sp. have the fewest (n = 240). The armadillo species with the most data is Dasypus novemcinctus (n = 11,588), and the fewest data are recorded for Calyptophractus retusus (n = 33). With regard to sloth species, Bradypus variegatus has the most records (n = 962), and Bradypus pygmaeus has the fewest (n = 12). Our main objective with Neotropical Xenarthrans is to make occurrence and quantitative data available to facilitate more ecological research, particularly if we integrate the xenarthran data with other data sets of Neotropical Series that will become available very soon (i.e., Neotropical Carnivores, Neotropical Invasive Mammals, and Neotropical Hunters and Dogs). Therefore, studies on trophic cascades, hunting pressure, habitat loss, fragmentation effects, species invasion, and climate change effects will be possible with the Neotropical Xenarthrans data set. Please cite this data paper when using its data in publications. We also request that researchers and teachers inform us of how they are using these data