Fitotoxidez do óleo essencial de Baccharis psiadioides (LESS.) JOCH. MULL. (ASTERACEAE: ASTERAE) na germinação de sementes : relações com o tamanho das sementes

Este trabalho visa preencher uma lacuna acerca do conhecimento dos efeitos fitotóxicos de óleos essenciais sobre a germinação de sementes. Especificamente, investigamos a possível relação do tamanho das sementes com a suscetibilidade aos efeitos fitotóxicos de um óleo essencial. Para tanto, um estudo em laboratório foi conduzido para determinação da sensibilidade de 21 acessos de sementes, variando em sua massa, ao efeito fitotóxico do óleo essencial de Baccharis psiadioides (Less.) Joch. Mull. durante a germinação. Cada acesso foi submetido a uma bateria de experimentos de dose-resposta, sendo seu nível de inibição calculado pela média da dose efetiva de inibição (ED50), que corresponde àquela dose de óleo essencial capaz de inibir a germinação de 50% da população de sementes de cada acesso comparado ao seu controle. Resultados mostraram uma correlação positiva entre o tamanho da semente e a ED50. As sementes menores necessitaram menores dosagens de óleo essencial para inibir a germinação, enquanto sementes maiores necessitaram uma maior dose de óleo essencial para inibição. Este padrão tem sido reportado para fitotoxinas em extratos aquosos com isoflavonoides, isotiocianatos, cumarinas e, agora, são reportados para óleos essenciais derivados de terpenos. Estes resultados trazem novas evidências sobre a ação de fitotoxinas e sua relação com o tamanho das sementes alvo de fitotoxidez, permitindo maior generalização acerca do tema e potenciais aplicações do conhecimento.This work aims to contribute to a better understanding of phytotoxic effects from essential oils on seeds germination. Specifically, the relationship between seed size and susceptibility to phytotoxic effects from an essential oil was investigated. A laboratory bioassays was conducted to determine the susceptibility of 21 seeds accessions, varying in their mass, to phytotoxic essential oil of Baccharis psiadioides (Less.) Joch. Mull. (Asteraceae) during germination. Each accession were submitted to dose-response experiments, and had its germination inhibition level by the essential oil calculated with the median effective dose (ED50), which corresponds to that dosage of essential oil capable of inhibiting the germination of 50% of the population compared to the control of each accession. Results showed a positive correlation between seed size and ED50. Small-seeded accessions needed lower dosages of essential oil to inhibit germination whereas larger-seeded accessions required higher doses for inhibition of germination. These pattern has been reported for phytotoxins in aqueous extracts with isoflavonoids, phenolic acid derivatives, isothiocyanates, coumarins and are now observed for essential oil derived from terpenoid pathway. These results provide new evidences on the action of phytotoxins and their relation with seed size and seed ecology, allowing broad generalization and potential applications. Effects reported herein may be a pattern for action of other essential oils, however, others studies may be conducted relating other seed attributes as seed reserve or embryo size

Evolução e sistemática de Cactos-Palma nas Américas : do campo à genômica

Plantas são fundamentais na natureza – e para a vida humana, fornecendo alimentos, remédios, fibras e vários outros recursos –, de modo que é imprescindível expandir nossos conhecimentos sobre a biodiversidade vegetal para seu uso sustentável. Cactos formam um dos grupos de plantas com flores mais fascinantes do mundo. Praticamente endêmicos das Américas, são conspícuos elementos das principais paisagens áridas, semiáridas, subúmidas e até tropicais do continente, exibindo uma alta diversidade de espécies, acompanhada por peculiaridades morfológicas, ecológicas e fisiológicas que despertam atenção. Dentre essa diversidade, os cactos-palma (Opuntia spp.) se destacam não só pela importância econômica e cultural, mas também por serem um dos mais ricos em número de espécies, e amplamente distribuídos ao longo das Américas. Visando preencher lacunas de conhecimento sobre os cactos-palma, especialmente no sul da América do Sul, integramos expedições de campo, coleções e pesquisas de herbário, observações morfológicas, dados moleculares e citogenéticos para investigar aspectos da sistemática e evolução do grupo. Nossos resultados revelaram-se extremamente importantes para contribuir com o conhecimento do grupo. Reportamos duas novas ocorrências para a flora do Brasil (Opuntia rioplatensis e O. bonaerensis) e uma para a do Uruguai (O. bonaerensis), além de reavaliar e tipificar uma espécie endêmica do Uruguai (O. canterae). Combinando dados morfológicos, moleculares e de modelagem de nicho ecológico, sugerimos que eventos de mudanças climática do Pleistoceno impactaram a distribuição de O. bonaerensis no sul da América do Sul; e revelamos que O. penicilligera, considerada endêmica da Argentina, é, provavelmente, derivada de espécies da América do Norte; e discutimos as afinidades morfológicas de O. ventanensis com O. fragilis, que também pode estar associada a uma origem Norte Americana. Nossos dados moleculares revelaram de maneira inédita a estrutura e o conteúdo do genoma plastidial (plastoma) de Opuntia quimilo, com importantes novidades acerca da evolução do plastoma em Cactaceae e na subfamília Opuntioideae. Baseado em dados do plastoma, circunscrevemos de maneira robusta Opuntioideae em três tribos (Opuntieae, Tephrocacteae e Cylindropuntieae) e exploramos marcadores úteis para futuros estudos filogenéticos no grupo. Nossos dados moleculares também contribuíram para identificar uma nova linhagem de vírus de DNA de fita simples infectando cactos, especialmente Opuntia. Análises filogenéticas moleculares e macroevolutivas demonstraram que Opuntia representa uma rápida e recente radiação evolutiva, que vem diversificando-se nos últimos 3 milhões de anos, com eventos de dispersão por longa-distância influenciando a distribuição atual do grupo, e com a homoplasia de vários caracteres morfológicos. A integração dos nossos dados de campo com moleculares também sustentou novidades nomenclaturais, combinando O. schickendantzii em Salmonopuntia, e revelando O. leoglossa como uma nova espécie para acomodar um táxon historicamente mal identificado. Combinando observações morfológicas, análises citogenéticas e inferências filogenéticas, sugerimos que hibridação é um processo que continua gerando diversidade em Opuntia, ao descrever um putativo novo híbrido que tem como possíveis parentais uma espécie do sul da América do Sul e uma espécie Norte Americana introduzida na América do Sul. Nossos estudos impulsionam um novo paradigma para o conhecimento dos cactos-palma nas Américas, ao integrar as mais diversas ferramentas para o estudo da biodiversidade, que deve contribuir para uma futura e necessária monografia do grupo.Plants are a keystone for nature – including for human life by providing food, medicine, fibers as well as many other resources –, so that it is essential to expand our knowledge about plant biodiversity for sustainable use. Cacti are one of the most fascinating groups of flowering plants. Mostly endemic of the Americas, they are conspicuous elements of major arid, semiarid, subhumid, and even tropical landscapes of the continent, exhibiting a high level of species diversity accompanied by morphological, physiological, and ecological peculiarities that have called attention. Among that diversity, the prickly-pears cacti (Opuntia spp.) stands out not only for their economic and cultural importance but also for being one of the most species-rich groups and widely distributed across the Americas. Aiming to contribute to our knowledge about the prickly- pears cacti, especially in southern South America, we have integrated fieldwork, collection-based research, morphological, molecular, and cytogenetics data to investigate aspects of the systematics and evolution of the group. Our study revealed to be extremely important to contribute with the knowledge regarding the prickly-pears diversity. We reported two new records for the Brazilian flora (Opuntia rioplatensis and O. bonaerensis) and for the Uruguayan (O. bonaerensis), in addition to the reassessment and typification of an endemic species of Uruguay (O. canterae). By combining morphological, molecular data and ecological niche modelling, we suggested that Pleistocene climatic events have impacted the distribution of O. bonaerensis in southern South America; and we showed that O. penicilligera, considered endemic of Argentina, is putatively derived from North American species; and we discussed morphological affinities between O. ventanensis and O. fragilis, which can also be associated with a North American origin. Our molecular data revealed for the first time the content and structure of the chloroplast genome (plastome) of an Opuntia, O. quimilo, with important insights into plastome evolution across Cactaceae and Opuntioideae. Based on plastome data, we robustly circumscribe Opuntioideae in three tribes (Opuntieae, Tephrocacteae, and Cylindropuntieae), and explored useful molecular markers for future phylogenetic studies in the group. Our molecular data also contributed to identify novel divergent lineages of single- stranded DNA virus infecting cacti, especially Opuntia. Molecular phylogenetics inferences and macroevolutionary analyses showed that Opuntia represents a rapid and recent evolutionary radiation, which are diversifying in the last 3 million years, with long-distance dispersal shaping the current distribution of the group, and the evolution of homoplasious morphological characters underlying their diversification. The integration of our field and molecular data also supported nomenclatural novelties, combining O. schickendantzii in Salmonopuntia, and unraveling O. leoglossa as a new species to accommodate a historically misidentified taxon. By combining morphological observations with cytogenetic analyses and molecular phylogenetic inferences, we suggested that hybridization is a process that still produces diversity within Opuntia, describing a putative new hybrid that has as likely parentals a southern South American species and a North American species introduced in South America. Our studies promote a new paradigm for the knowledge of prickly pear cacti in the Americas, by integrating diverse approaches for the biodiversity study, which should contribute to a future and needed botanical monograph of the group

Reassessment and typification of Opuntia canterae (Opuntioideae, Cactaceae), an endemic prickly pear cactus of Uruguay

Background and aims – Opuntia is the most widespread genus of Cactaceae, naturally occurring throughout arid and semi-arid areas of the Americas. Many of the species have taxonomic problems resulting from incomplete original descriptions, lack of type designations, a paucity of taxonomic revisions and, in general, difficult species delimitation resulting from hybridization, morphological plasticity, and poor specimen preparation. However, efforts are being undertaken to fill the gaps in our distributional, morphological and phylogenetic knowledge of the group. Here, we reassess the name Opuntia canterae, providing an updated description, typification, photographs, distribution map, conservation assessment and additional notes. Material and methods – Extensive fieldwork was conducted, along with comprehensive herbarium and literature review. Morphological characters were assessed based on the commonly used characters used for prickly pears. Species delimitation is proposed based on our morphological studies, taxonomic and literature revision, as well as preliminary phylogenetic studies. The IUCN guidelines were followed to provide a conservation assessment of the species.Key results – Opuntia canterae is reassessed as a distinct species separated from its previous synonym (O. elata) by the elliptic to long-oblanceolate stem segments, acute to conical flower bud apex and long-obconic fruits. An epitype is here designated to further clarify the morphological features of the species, which, heretofore, were only represented by a photo. The species is considered endemic to Uruguay and is provisionally assessed as Endangered (EN) using IUCN criteria, but more fieldwork will be necessary to provide a further precise conservation status

Insights into Chloroplast genome evolution across Opuntioideae (Cactaceae) reveals robust yet sometimes conflicting phylogenetic topologies

Chloroplast genomes (plastomes) are frequently treated as highly conserved among land plants. However, many lineages of vascular plants have experienced extensive structural rearrangements, including inversions and modifications to the size and content of genes. Cacti are one of these lineages, containing the smallest plastome known for an obligately photosynthetic angiosperm, including the loss of one copy of the inverted repeat (∼25 kb) and the ndh gene suite, but only a few cacti from the subfamily Cactoideae have been sufficiently characterized. Here, we investigated the variation of plastome sequences across the second-major lineage of the Cactaceae, the subfamily Opuntioideae, to address (1) how variable is the content and arrangement of chloroplast genome sequences across the subfamily, and (2) how phylogenetically informative are the plastome sequences for resolving major relationships among the clades of Opuntioideae. Our de novo assembly of the Opuntia quimilo plastome recovered an organelle of 150,347 bp in length with both copies of the inverted repeat and the presence of all the ndh gene suite. An expansion of the large single copy unit and a reduction of the small single copy unit was observed, including translocations and inversion of genes, as well as the putative pseudogenization of some loci. Comparative analyses among all clades within Opuntioideae suggested that plastome structure and content vary across taxa of this subfamily, with putative independent losses of the ndh gene suite and pseudogenization of genes across disparate lineages, further demonstrating the dynamic nature of plastomes in Cactaceae. Our plastome dataset was robust in resolving three tribes with high support within Opuntioideae: Cylindropuntieae, Tephrocacteae and Opuntieae. However, conflicting topologies were recovered among major clades when exploring different assemblies of markers. A plastome-wide survey for highly informative phylogenetic markers revealed previously unused regions for future use in Sanger-based studies, presenting a valuable dataset with primers designed for continued evolutionary studies across Cactaceae. These results bring new insights into the evolution of plastomes in cacti, suggesting that further analyses should be carried out to address how ecological drivers, physiological constraints and morphological traits of cacti may be related with the common rearrangements in plastomes that have been reported across the family

Cactaceae at Caryophyllales.org- A dynamic online species-level taxonomic backbone for the family

This data paper presents a largely phylogeny-based online taxonomic backbone for the Cactaceae compiled from literature and online sources using the tools of the EDIT Platform for Cybertaxonomy. The data will form a contribution of the Caryophyllales Network for the World Flora Online and serve as the base for further integration of research results from the systematic research community. The final aim is to treat all effectively published scientific names in the family. The checklist includes 150 accepted genera, 1851 accepted species, 91 hybrids, 746 infraspecific taxa (458 heterotypic, 288 with autonyms), 17,932 synonyms of accepted taxa, 16 definitely excluded names, 389 names of uncertain application, 672 unresolved names and 454 names belonging to (probably artificial) named hybrids, totalling 22,275 names. The process of compiling this database is described and further editorial rules for the compilation of the taxonomic backbone for the Caryophyllales Network are proposed. A checklist depicting the current state of the taxonomic backbone is provided as supplemental material. All results are also available online on the website of the Caryophyllales Network and will be constantly updated and expanded in the future. Citation: Korotkova N., Aquino D., Arias S., Eggli U., Franck A., Gómez-Hinostrosa C., Guerrero P. C., Hernández H. M., Kohlbecker A., Köhler M., Luther K., Majure L. C., Müller A., Metzing D., Nyffeler R., Sánchez D., Schlumpberger B. & Berendsohn W. G. 2021: Cactaceae at Caryophyllales.org- A dynamic online species-level taxonomic backbone for the family.-Willdenowia 51: 251-270. Version of record first published online on 31 August 2021 ahead of inclusion in August 2021 issue. Data published through: Http://caryophyllales.org/cactaceae/Checklis

Incubadora tecnológica de cooperativas populares - ITCP/UFRGS

O trabalho está inserido em uma ação de extensão promovida pela Incubadora Tecnológica de Cooperativas Populares (ITCP) e pelo NEA (Núcleo de Economia Alternativa). Objetiva-se a melhoria das condições de vida e de trabalho para um grupo organizado de mulheres do Assentamento Filhos de Sepé, localizado na cidade de Viamão - RS

Severe forms of partial androgen insensitivity syndrome due to p.L830F novel mutation in androgen receptor gene in a Brazilian family

<p>Abstract</p> <p>Background</p> <p>The androgen insensitivity syndrome may cause developmental failure of normal male external genitalia in individuals with 46,XY karyotype. It results from the diminished or absent biological action of androgens, which is mediated by the androgen receptor in both embryo and secondary sex development. Mutations in the androgen receptor gene, located on the X chromosome, are responsible for the disease. Almost 70% of 46,XY affected individuals inherited mutations from their carrier mothers.</p> <p>Findings</p> <p>Molecular abnormalities in the androgen receptor gene in individuals of a Brazilian family with clinical features of severe forms of partial androgen insensitivity syndrome were evaluated. Seven members (five 46,XY females and two healthy mothers) of the family were included in the investigation. The coding exons and exon-intron junctions of androgen receptor gene were sequenced. Five 46,XY members of the family have been found to be hemizygous for the c.3015C>T nucleotide change in exon 7 of the androgen receptor gene, whereas the two 46,XX mothers were heterozygote carriers. This nucleotide substitution leads to the p.L830F mutation in the androgen receptor.</p> <p>Conclusions</p> <p>The novel p.L830F mutation is responsible for grades 5 and 6 of partial androgen insensitivity syndrome in two generations of a Brazilian family.</p

New World Cactaceae Plants Harbor Diverse Geminiviruses

The family Cactaceae comprises a diverse group of typically succulent plants that are native to the American continent but have been introduced to nearly all other continents, predominantly for ornamental purposes. Despite their economic, cultural, and ecological importance, very little research has been conducted on the viral community that infects them. We previously identified a highly divergent geminivirus that is the first known to infect cacti. Recent research efforts in non-cultivated and asymptomatic plants have shown that the diversity of this viral family has been under-sampled. As a consequence, little is known about the effects and interactions of geminiviruses in many plants, such as cacti. With the objective to expand knowledge on the diversity of geminiviruses infecting cacti, we used previously acquired high-throughput sequencing results to search for viral sequences using BLASTx against a viral RefSeq protein database. We identified two additional sequences with similarity to geminiviruses, for which we designed abutting primers and recovered full-length genomes. From 42 cacti and five scale insects, we derived 42 complete genome sequences of a novel geminivirus species that we have tentatively named Opuntia virus 2 (OpV2) and 32 genomes of an Opuntia-infecting becurtovirus (which is a new strain of the spinach curly top Arizona virus species). Interspecies recombination analysis of the OpV2 group revealed several recombinant regions, in some cases spanning half of the genome. Phylogenetic analysis demonstrated that OpV2 is a novel geminivirus more closely related to viruses of the genus Curtovirus, which was further supported by the detection of three recombination events between curtoviruses and OpV2. Both OpV2 and Opuntia becurtoviruses were identified in mixed infections, which also included the previously characterized Opuntia virus 1. Viral quantification of the co-infected cactus plants compared with single infections did not show any clear trend in viral dynamics that might be associated with the mixed infections. Using experimental Rhizobium-mediated inoculations, we found that the initial accumulation of OpV2 is facilitated by co-infection with OpV1. This study shows that the diversity of geminiviruses that infect cacti is under-sampled and that cacti harbor diverse geminiviruses. The detection of the Opuntia becurtoviruses suggests spill-over events between viruses of cultivated species and native vegetation. The threat this poses to cacti needs to be further investigated