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RNA editing is a post-transcriptional process that challenges the central dogma of molecular biology by modifying RNA sequences, introducing nucleotide changes at specific sites, and generating functional diversity beyond the genomic code, especially when it concerns organellar transcripts. In plants, this phenomenon is widespread, but its extent varies significantly among species and organellar genomes. Among land plants, the heterosporous lycophytes (i.e., Isoetes and Selaginella) stand out for their exceptionally high numbers of RNA-editing sites, despite their morphological stasis and ancient lineage. In this study, we explore the complete set of organellar protein-coding genes in the aquatic plant group Isoetes, providing a detailed analysis of RNA editing in both the mitochondrial and plastid genomes. Our findings reveal a remarkable abundance of RNA editing, particularly in the mitochondrial genome, with thousands of editing sites identified. Interestingly, the majority of these edits result in non-silent substitutions, suggesting a role in fine-tuning protein structure and function. Furthermore, we observe a consistent trend of increased hydrophobicity in membrane-bound proteins, supporting the notion that RNA editing may confer a selective advantage by preserving gene functionality in Isoetes. The conservation of highly edited RNA sequences over millions of years underscores the evolutionary significance of RNA editing. Additionally, the study sheds light on the dynamic nature of RNA editing, with shared editing sites reflecting common ancestry whereas exclusive edits matching more recent radiation events within the genus. This work advances our understanding of the intricate interplay between RNA editing, adaptation, and evolution in land plants and highlights the unique genomic features of Isoetes, providing a foundation for further investigations into the functional consequences of RNA editing in this enigmatic plant lineage.

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INTRODUCTION: Selaginellins are specialized metabolites and chemotaxonomic markers for Selaginella species. Despite the growing interest in these compounds as a result of their bioactivities, they are accumulated at low levels in the plant. Hence, their isolation and chemical characterization are often difficult, time consuming, and limiting for biological tests. Elicitation with the phytohormone methyl jasmonate (MeJA) could be a strategy to increase the content of selaginellins addressing their low availability problem, that also impairs pharmacological investigations. MATHERIALS AND METHODS: In this study, we examined MeJA elicitation in Selaginella convoluta plants, a medicinal plant found in northeastern Brazil, by treating them with two different concentrations (MeJA: 50 and 100 µM), followed by chemical profiling after 12, 24 and 48 h after application. Samples were harvested and analyzed by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). RESULTS AND DISCUSSCION: MeJA treatment significantly impacted the chemical phenotype. Regarding shoots differences in the time-dependent increased accumulation of all metabolites when plants were subjected to 100 µM MeJA were observed while in roots, most metabolites had their concentrations decreased in a time-dependent fashion at the same conditions. Results support organ, MeJA concentration and time post-treatment dependence of specialized metabolite accumulation, mainly the flavonoids and selaginellins. The amount of Selaginellin G in shoots of MeJA-treated specimens increased in 5.63-fold relative to control. The molecular networking approach allowed for the putative annotation of 64 metabolites, among them, the MeJA treatment followed by targeted metabolome analysis also allowed to annotate seven unprecedented selaginellins. Additionally, the in silico bioactive potential of the annotated selaginellins highlighted targets related to neurodegenerative disorders, antiproliferative, and antiparasitic issues. Taken together, data point out MeJA exposure as a strategy to induce potentially bioactive selaginellins accumulation in S. convoluta, this approach could enable a deep investigation about the metabolic function of these metabolites in the genus as well as regarding pharmacological exploration of the undervalued potential.

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Resumen Los helechos y licófitos mencionados en El mundo Vegetal de los Andes peruanos de Weberbauer brindan una breve información de su riqueza y sustento a las observaciones ambientales para cada categoría de su esquema fitogeográfico del Perú. Este estudio actualiza tanto el concepto y características de los pteridofitos mencionados en el capítulo Unidades Sistemáticas, como la nomenclatura de los 126 nombres de los taxones mencionados en la obra. Además, se ofrece una breve historia del estudio del grupo en el Perú, para proveer el contexto de la inclusión de estas plantas por Weberbauer. Y se mencionan las colecciones que Weberbauer realizara del grupo y, en particular, las citadas como ejemplos. Se ofrece un perfil de las tareas por realizar para completar la labor biogeográfica iniciada por Weberbauer.

Abstract Ferns and lycophytes were mentioned by Weberbauer in his El mundo Vegetal de los Andes peruanos to provide a hint of the richness of the group and to support his natural history observations for each category of his phytogeographic description of Peru. This contribution updates concepts and features of these plants as discussed in the chapter on "Systematic Units" and updates the 126 names of taxa cited in his book. To this end, we provide a brief history of the development of Peru's pteridoflora studies in the context of Weberbauer's work. We also document Weberbauer's pteridophyte collections linked to the verification of the taxa of his examples. A framework for future research is provided to complete the biogeographic endeavor that begun with his work and highlights the need to relocate his plant collections as witnesses of his legacy.

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BACKGROUND: The LEAFY (LFY) transcription factors are present in algae and across land plants. The available expression and functional data of these genes in embryophytes suggest that LFY genes control a plethora of processes including the first zygotic cell division in bryophytes, shoot cell divisions of the gametophyte and sporophyte in ferns, cone differentiation in gymnosperms and floral meristem identity in flowering plants. However, their putative plesiomorphic role in plant reproductive transition in vascular plants remains untested. RESULTS: We perform Maximum Likelihood (ML) phylogenetic analyses for the LFY gene lineage in embryophytes with expanded sampling in lycophytes and ferns. We recover the previously identified seed plant duplication that results in LEAFY and NEEDLY paralogs. In addition, we recover multiple species-specific duplications in ferns and lycophytes and large-scale duplications possibly correlated with the occurrence of whole genome duplication (WGD) events in Equisetales and Salviniales. To test putative roles in diverse ferns and lycophytes we perform LFY expression analyses in Adiantum raddianum, Equisetum giganteum and Selaginella moellendorffii. Our results show that LFY genes are active in vegetative and reproductive tissues, with higher expression in early fertile developmental stages and during sporangia differentiation. CONCLUSIONS: Our data point to previously unrecognized roles of LFY genes in sporangia differentiation in lycophytes and ferns and suggests that functions linked to reproductive structure development are not exclusive to seed plant LFY homologs.

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The genus Isoëtes is globally distributed. Within the Neotropics, Isoëtes occurs in various habitats and ecosystems, making it an interesting case study to address phylogenetic and biogeographic questions. We sequenced and assembled plastomes and ribosomal DNA (rDNA) sequences to reconstruct phylogenetic relationships in Isoëtes from tropical regions in the Neotropics. The ploidy level of nine taxa was established to address the potential source of phylogenetic incongruence in the genus. Node ages were estimated using MCMCTree. The ancestral range estimates were conducted in BioGeoBEARS. Plastome-based phylogenies were congruent throughout distinct matrices and partition schemes, exhibiting high support for almost all nodes. Whereas, we found incongruences between the rDNA and plastome datasets. Chromosome counts identified three diploids, five tetraploids and one likely hexaploid among Neotropical species. Plastome-based node age estimates showed that the radiation of the crown Isoëtes group occurred at 20 Ma, with the diversification of the tropical American (TAA) clade taking place in the Pleistocene at 1.7 Ma. Ancestral range estimates showed that the ancestor of the TAA clade may have evolved first in the dry diagonal area in South America before reaching more humid regions. In addition, the colonization of the Brazilian semiarid region occurred three times, while the occupation of the Cerrado and Amazon regions occurred twice and once, respectively. Our study showed a large unobserved diversity within the genus in warm-dry regions in the Neotropics. Plastomes provided sufficient genomic information to establish a robust phylogenetic framework to answer evolutionary questions in Isoëtes from the Neotropics.

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BACKGROUND: Brazil is one of the most biodiverse countries in the world, with about 37,000 species of land plants. Part of this biodiversity is within protected areas. The development of online databases in the last years greatly improved the available biodiversity data. However, the existing databases do not provide information about the protected areas in which individual plant species occur. The lack of such information is a crucial gap for conservation actions. This study aimed to show how the information captured from online databases, cleaned by a protocol and verified by taxonomists allowed us to obtain a comprehensive list of the vascular plant species from the "Parque Nacional do Itatiaia", the first national park founded in Brazil. All existing records in the online database JABOT (15,100 vouchers) were downloaded, resulting in 11,783 vouchers identified at the species level. Overall, we documented 2,316 species belonging to 176 families and 837 genera of vascular plants in the "Parque Nacional do Itatiaia". Considering the whole vascular flora, 2,238 species are native and 78 are non-native. NEW INFORMATION: The "Parque Nacional do Itatiaia" houses 13% of the angiosperm and 37% of the fern species known from the Brazilian Atlantic Forest. Amongst these species, 82 have been cited as threatened, following IUCN categories (CR, EN or VU), seven are data deficient (DD) and 15 have been classified as a conservation priority, because they are only known from a single specimen collected before 1969.

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BACKGROUND AND AIMS: Tropical understorey plant communities are highly diverse and characterized by variable resource availability, especially light. Plants in these competitive environments must carefully partition resources to ensure ecological and evolutionary success. One mechanism of effective resource partitioning is the optimization of functional traits to enhance competition in highly heterogeneous habitats. Here, we surveyed the ecophysiology of two early lineage vascular plant groups from a tropical forest understorey: Selaginella (a diverse lineage of lycophytes) and ferns. METHODS: In a lowland rain forest in Costa Rica, we measured a suite of functional traits from seven species of Selaginella and six fern species. We evaluated species microclimate and habitat; several photosynthetic parameters; carbon, nitrogen and phosphorus content; chlorophyll concentration; leaf mass per area (LMA); and stomatal size and density. We then compare these two plant lineages and search for relationships between key functional parameters that already exist on a global scale for angiosperms. KEY RESULTS: Convergence of trait function filtered Selaginella species into different habitats, with species in heavily shaded environments having higher chlorophyll concentrations and lower light compensation points compared with open habitats. Alternatively, lower foliar nitrogen and higher stomatal densities were detected in species occupying these open habitats. Selaginella species had denser and smaller stomata, lower LMA and lower foliar nutrient content than ferns, revealing how these plant groups optimize ecophysiological function differently in tropical forest floors. CONCLUSIONS: Our findings add key pieces of missing evidence to global explorations of trait patterns that define vascular plant form and function, which largely focus on seed plants. Broadly predictable functional trait relationships were detected across both Selaginella and ferns, similar to those of seed plants. However, evolutionary canalization of microphyll leaf development appears to have driven contrasting, yet successful, ecophysiological strategies for two coexisting lineages of extant homosporous vascular plants.

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We describe four new species in the genus Selaginella (i.e., S. agioneuma, S. magnafornensis, S. ventricosa, and S. zartmanii) from Brazil, all presently classified in subg. Stachygynandrum. For each of the new taxa we discuss taxonomic affinities and provide information on habitat, distribution, and conservation status. In addition, line drawings and scanning electron microscope (SEM) images of stems sections, leaves, and spores (when present) are included. Selaginella agioneuma and S. magnafornensis are from the State of Espíritu Santo where they inhabit premontane to montane Atlantic rain forests in the Reserva Biológica Augusto Ruschi and Parque Estadual Forno Grande, respectively. Selaginella ventricosa was collected in upper montane forests at Parque Nacional Serra da Mocidade, State of Roraima and S. zartmanii in premontane Amazon rain forests on upper Rio Negro at Mpio. São Gabriel da Cachoeira, Amazonas State in both Serra Curicuriari and the Morro dos Seis Lagos Biological Reserve.

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The Neotropical clade of the lycophyte genus Phlegmariurus is comprised of an estimated 150 described species and exhibits exceptional morphological and ecological diversity. Because of their simple morphology, frequent convergent evolution, and the recentness of the group's diversification, the delimitation of species and species groups has remained challenging. Here, we present a robustly support phylogeny of Neotropical Phlegmariurus based on six chloroplast markers and ca. 70% of known species, and use ancestral character state reconstruction to investigate morphological evolution in the clade, and define natural species groups. The Neotropical species of Phlegmariurus form a clade that also includes a small number of Afro-Madagascan species. A morphologically and ecologically variable group of species from southeastern Brazil form a monophyletic group and represent a parallel radiation to principally Andean lineages. Species groups in Neotropical Phlegmariurus that were previously recognized based on morphology are not monophyletic. We find support for 11 morphologically cohesive and well-supported species groups. Morphological homoplasy is common in Phlegmariurus and complicates infrageneric classification of the Neotropical taxa. Our results provide a useful framework for identifying species groups and understanding patterns of morphological evolution in Neotropical Phlegmariurus. The radiation of the Brazilian species remains poorly understood and requires further study.

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Abstract Galls are neo-formed plant structures induced by species-specific interaction between an inducing organism and a host plant. Lycophytes and ferns are two distinct plant lineages historically lumped together as pteridophytes. A number of authors suggest low gall frequency in lycophytes and ferns, compared to angiosperms. This study aimed at compiling an updated overview of fern galls in Brazil, providing information on hosts, gall-inducing organisms and associated fauna. The synopsis was compiled using existent data and by updating scientific names and gathering new information obtained by the authors in fieldwork. To date, galls have been recorded on 16 fern species but none on lycophytes. However, the inducer was identified at species level in only three gall morphotypes from three fern species, with a doubtful inducer for Pteridium sp. Galls are induced by mites (Eriophyidae) and insects of the orders Diptera, Lepidoptera, Thysanoptera, and Hemiptera, Cecidomyiidae (Diptera) being the most frequent galler insect.

Resumo Galhas são estruturas vegetais neoformadas induzidas por interações espécie-específicas entre um organismo indutor e uma planta hospedeira. Licófitas e samambaias são duas linhagens de plantas historicamente classificadas juntas como pteridófitas. Diversos autores sugerem que há uma baixa frequência de galhas em licófitas e samambaias, em comparação com as angiospermas. Este trabalho tem como objetivo fornecer um panorama atualizado sobre as galhas em samambaias no Brasil, disponibilizando informações sobre espécies hospedeiras, galhadores e fauna associada. A sinopse foi realizada compilando-se os dados existentes, atualizando os nomes científicos e agregando informações novas obtidas pelos autores em trabalhos de campo. Até o momento, foram registradas galhas em 16 espécies de samambaias e nenhum registro em licófitas. Contudo, em apenas três morfotipos de galhas, de três espécies de samambaias, o indutor foi identificado a nível de espécie, com um indutor duvidoso para Pteridium sp. As galhas são induzidas por ácaros (Eriophyidae) e insetos das ordens: Diptera, Lepidoptera, Thysanoptera, Hemiptera, sendo Cecidomyiidae (Diptera) o galhador mais frequente.

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Isoetes nana, a new species from the coastal mountains of southeastern Brazil (Serra de Itatiaia), is described, illustrated and compared to similar species. This species can be distinguished from similar species by a set of characters that include 5-15 small erect leaves reaching only up to 3.5cm long, megaspores rugulate (rarely laevigate or obscurely cristate) and microspores sparsely echinate. We include a key to identify this new species and spore images for all species that are discussed in this study. Isoetes nana is known only from the type locality, where it was reported to occur in small ponds on rocky outcrops at high elevations. We suggest it should be classified as a data deficient species based on the IUCN criteria.

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In this paper, I describe five new species of Selaginella from Brazil (Selaginella nanuzae, Selaginella neospringiana, Selaginella pellucidopunctata, Selaginella stomatoloma, and Selaginella trygonoides), compare them to morphologically similar species, and provide a preliminary conservation status assessment for each. The new species are illustrated with scanning electron photomicrographs of stem sections, leaves, and spores, when available. Also discussed in this paper are ten species, mainly from Brazil and with new distribution records, and the forthcoming resurrection of three species also occurring in Brazil. Three further non-native and presumed naturalized species are recognized in Brazil, and publication of one additional taxon is planned. Eighty-six Selaginella species are now known from Brazil and, of these, 80 are native (including 26 / 32.5%, endemic), and six are introduced. Brazil and Mexico have the second highest number of native Selaginella species in the Neotropics after Venezuela, which is estimated to have about 100. Of the newly documented species, Selaginella cabrerensis is now known to occur in French Guiana, Brazil, and Bolivia, in addition to Colombia, and Selaginella arroyoana and Selaginella chiquitana are synonymized under it. Likewise, Selaginella potaroensis is also recorded from Costa Rica and Brazil, and Selaginella seemannii from Panama and Brazil. Finally, leaf marginal stomata are reported on the newly described species and their functionality is discussed under Selaginella stomatoloma.

ResumenEn este artículo describo cinco nuevas especies de Selaginella de Brasil (Selaginella nanuzae, Selaginella neospringiana, Selaginella pellucidopunctata, Selaginella stomatoloma y Selaginella trygonoides), las cuales comparo con especies morfológicamente similares y estimo, preliminarmente, su estado de conservación. Las nuevas especies las ilustro con fotomicrografías al microscopio electrónico de barrido de secciones de los tallos, hojas y esporas (cuando están disponibles). Diez especies adicionales son discutidas en este artículo con nuevos registros, mayormente para Brasil, y la resurrección de otras tres también presentes en este país es anunciada. Tres especies introducidas y presuntamente naturalizadas adicionales son documentadas en Brasil, mientras que se anuncia la publicación próximamente de una especie nueva que también ocurre en este país. Por lo tanto, la ocurrencia de 86 especies de Selaginella en Brasil es conocida ahora, de las cuales 80 son nativas (26 de ellas o el 32.5% son endémicas) y seis son introducidas. Brasil y México tienen el segundo mayor número de especies nativas de Selaginella en el Neotrópico, después de Venezuela que se estima que posee unas 100. De las especies documentadas por primera vez, Selaginella cabrerensis se reconoce que está distribuida en Guayana Francesa, Brasil y Bolivia, además de Colombia, y se consideran formalmente como sinónimo de ésta a Selaginella arroyoana y a Selaginella chiquitana. Adicionalmente, Selaginella potaroensis es documentada en Costa Rica y Brasil, al igual que lo es Selaginella seemannii en Panamá y Brasil. Finalmente, la presencia de estomas en los márgenes de las hojas se reporta en las cinco nuevas especies descritas y su funcionalidad se discute bajo Selaginella stomatoloma.

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The extreme conditions in rocky outcrops allow the occurrence of desiccation tolerant species. One strategy of these plants to withstand water shortage is the accumulation of sugars. In this paper, we report sugar levels and profile of three ferns and one lycophyte naturally hydrated growing on rocky outcrops from Southeastern Brazil. Anemia species have higher sugar contents than Doryopteris collina and Selaginella sellowii. The analyzed species have different sugar profiles. The ferns have glucose, fructose and sucrose, and the lycophyte has glucose and trehalose.

Nas condições ambientais extremas dos afloramentos rochosos ocorrem espécies tolerantes à dessecação. Uma das estratégias dessas plantas para resistir à restrição hídrica é o acúmulo de açúcares. No presente estudo, avaliamos a concentração e o perfil de açúcares de três espécies de samambaias e uma licófita, naturalmente hidratadas crescendo sobre afloramentos rochosos no sudeste do Brasil. As espécies de Anemia possuem maior concentração de açúcares em relação a Doryopteris collina e Selaginella sellowii. As espécies analisadas mostraram perfis distintos de açúcares. As samambaias apresentam glicose, frutose e sacarose, enquanto a licófita glicose e trealose.

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Diversity of ferns and lycophytes from Reserva Natural Punta Lara, Buenos Aires , Argentina. Punta Lara Natural Reserve shelters the relict of the Southernmost riparian forest in the world, where the flora is threatened by the anthropic expansion and by the introduction of exotic species. In this area the ferns and lycophytes grow in particular environments as marshland, grassland and marginal forest. The aim of this work was to evaluate the diversity of ferns and lycophytes that inhabit in Punta Lara Natural Reserve. Field trips were conducted from 2006 to 2009 and local herbaria and specific bibliography were also revised. As a result of our study twenty four taxa of ferns and lycophytes were recognized. Their habit was mainly terrestrial (70%), fewer aquatic (17%) and epiphytic (13%). Five native taxa were scarcely recorded whereas two native species previously documented were not found. We assume that the main threats on ferns and lycophytes populations in Punta Lara Reserve are: removal for comercialization, invasion by exotic species and climatic fluctuations (drought periods). Keys for taxa identification are given and strategies for the conservation of threatened taxa are proposed. Rev. Biol. Trop. 59 (3): 1037-1046. Epub 2011 September 01.

Hasta el año 1987 el número de helechos y licofitas citados para la Reserva Punta Lara era de 30, incluyendo taxa específicos e infraespecíficos. El objetivo de este trabajo fue evaluar la diversidad de los helechos y licofitas que crecen en esta reserva, donde se halla el relicto más austral de las selvas en galería. Para llevar a cabo este estudio se realizaron viajes de campo durante los años 2006-2009 y se consultaron herbarios locales así como bibliografía especializada. Como resultado del estudio se determinaron 24 taxa de helechos y licofitas, de hábito predominantemente terrestre (70%); pocas acuáticas (17%) y epífitas (13%); dos especies exóticas, mientras que otras dos especies nativas citadas previamente no fueron halladas. Cinco taxa fueron registrados con escasa frecuencia. Se infiere que las principales causas de amenaza para las poblaciones de licofitas y helechos en la Reserva Natural Punta Lara son la extracción para su comercialización, la introducción de plantas exóticas y las fluctuaciones climáticas (periodos de sequía). Se presenta una clave de identificación de los taxa registrados y se plantean futuras estrategias de conservación de las especies consideradas vulnerables.

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Presence, abundance and reproductive strategies of ferns in disturbed areas of Sierra Nevada, México. Diverse reproductive strategies shown by ferns and lycophytes allow them to colonize a variety of habitats, particularly after the incidence of natural or anthropogenic disturbances. This study assessed the presence, abundance and reproductive strategies of ferns growing in soils of temperate forests with different levels of disturbance at the Sierra Nevada mountain range in the State of Mexico. Vegetation, soil and environmental variables were recorded in 200m² permanent plots located in four forest stands. One-Way ANOVA and Canonical Correspondence Analysis resulted in the recognition of three landscape types defined by the degree of environmental alteration: low, moderate and severe. Also, from five soil samples collected in each stand, germination of ferns and lycophytes was induced. A positive relationship was found between the alteration degree and Cheilanthes abundance. Under a low landscape alteration regime, species richness is restricted to Cheilanthes bonariensis, C. marginata and Pellaea ternifolia subsp. ternifolia. The soil is a reservoir of spores of Cheilanthes and Pellaea ternifolia subsp. ternifolia because their spores can remain viable for different time intervals. Apogamy is the usual reproductive strategy of Cheilanthes species in disturbed ecosystems, although these species also show sexual reproduction in natural ecosystems with adequate water availability. Apogamy may be related to a shorter generation time in comparison with a low disturbed ecosystem. On the other hand, Pellaea ternifolia subsp. ternifolia only has sexual reproduction. Apogamy might be related to a faster generation in comparison with a low disturbed ecosystem. Rev. Biol. Trop. 59 (1): 417-433. Epub 2011 March 01.

Los helechos y licófitas tienen diversas estrategias reproductivas que las habilitan para invadir ambientes perturbados y áreas sin vegetación. En este trabajo se estudió la presencia, abundancia y estrategias reproductivas de individuos que crecen en suelos de bosques templados, en la Sierra Nevada, Estado de México. Se eligieron cuatro zonas en las que se instaló un cuadrante permanente de 200m² para cada una, con el fin de registrar variables edáficas, ambientales y de vegetación. La relación entre variables se pudo explorar con análisis de varianza y Análisis Canónico de Correspondencia dando como resultado tres paisajes con base en el grado de alteración ambiental: baja, moderada y severa. Fueron recolectadas cinco muestras de suelo en cada zona para inducir la germinación de helechos y licofitas, obteniendo resultados que revelan una relación positiva entre el grado de alteración y la abundancia de Cheilanthes. En paisajes con baja alteración, la riqueza de especies fue mayor comparada con paisajes de alteración severa, en la que la presencia de especies se redujo a Cheilanthes bonariensis, C. marginata y Pellaea ternifolia subsp. ternifolia. El suelo fue un banco de esporas de Cheilanthes y Pellaea ternifolia subsp. ternifolia ya que las esporas permanecieron viables por diferentes intervalos de tiempo. La apogamia fue la estrategia reproductiva común para especies de Cheilanthes en ecosistemas alterados, aunque estas especies tienen reproducción sexual en ecosistemas naturales con suficiente agua. Por otro lado, Pellaea ternifolia subsp. ternifolia solo presentó reproducción sexual. La apogamia puede estar relacionada con que la alternancia de generaciones se realice en menos tiempo, comparado con un ecosistema de baja alteración.

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