Macroevolutionary decline in mycorrhizal colonization and chemical defense responsiveness to mycorrhization

Arbuscular mycorrhizal fungi (AMF) have evolved associations with roots of 60% plant species, but the net benefit for plants vary broadly from mutualism to parasitism. Yet, we lack a general understanding of the evolutionary and ecological forces driving such variation. To this end, we conducted a comparative phylogenetic experiment with 24 species of Plantago, encompassing worldwide distribution, to address the effect of evolutionary history and environment on plant growth and chemical defenses in response to AMF colonization. We demonstrate that different species within one plant genus vary greatly in their ability to associate with AMF, and that AMF arbuscule colonization intensity decreases monotonically with increasing phylogenetic branch length, but not with concomitant changes in pedological and climatic conditions across species. Moreover, we demonstrate that species with the highest colonization levels are also those that change their defensive chemistry the least. We propose that the costs imposed by high AMF colonization in terms of reduced changes in secondary chemistry might drive the observed macroevolutionary decline in mycorrhization.

Travel Tales of a Worldwide Weed: Genomic Signatures of Plantago major L. Reveal Distinct Genotypic Groups With Links to Colonial Trade Routes

Retracing pathways of historical species introductions is fundamental to understanding the factors involved in the successful colonization and spread, centuries after a species' establishment in an introduced range. Numerous plants have been introduced to regions outside their native ranges both intentionally and accidentally by European voyagers and early colonists making transoceanic journeys; however, records are scarce to document this. We use genotyping-by-sequencing and genotype-likelihood methods on the selfing, global weed, Plantago major, collected from 50 populations worldwide to investigate how patterns of genomic diversity are distributed among populations of this global weed. Although genomic differentiation among populations is found to be low, we identify six unique genotype groups showing very little sign of admixture and low degree of outcrossing among them. We show that genotype groups are latitudinally restricted, and that more than one successful genotype colonized and spread into the introduced ranges. With the exception of New Zealand, only one genotype group is present in the Southern Hemisphere. Three of the most prevalent genotypes present in the native Eurasian range gave rise to introduced populations in the Americas, Africa, Australia, and New Zealand, which could lend support to the hypothesis that P. major was unknowlingly dispersed by early European colonists. Dispersal of multiple successful genotypes is a likely reason for success. Genomic signatures and phylogeographic methods can provide new perspectives on the drivers behind the historic introductions and the successful colonization of introduced species, contributing to our understanding of the role of genomic variation for successful establishment of introduced taxa.

Molecular and Morphological Data Improve the Classification of Plantagineae (Lamiales)

The tribe Plantagineae (Lamiales) is a group of plants with worldwide distribution, notorious for its complicated taxonomy and still unresolved natural history. We describe the result of a broadly sampled phylogenetic study of tribe. The expanded sampling dataset is based on the trnL-F spacer, rbcL, and ITS2 markers across all three included genera (Aragoa, Littorella and Plantago) and makes this the most comprehensive study to date. The other dataset uses five markers and provides remarkably good resolution throughout the tree, including support for all of the major clades. In addition to the molecular phylogeny, a morphology database of 114 binary characters was assembled to provide comparison with the molecular phylogeny and to develop a means to assign species not sampled in the molecular analysis to their most closely related species that were sampled. Based on the molecular phylogeny and the assignment algorithm to place unsampled species, a key to sections is presented, and a revised classification of the tribe is provided. We also include the description of new species from North America.

Plantago campestris (Plantaginaceae), a rare new species from southern Brazil, supported by phylogenomic and morphological evidence

High-throughput sequencing, when combined with taxonomic expertise, is a powerful tool to refine and advance taxonomic classification, including at the species level. In the present work, a new species, Plantago campestris, is described out of the P. commersoniana species complex, based on phylogenomic and morphological evidence. The main morphological characters that distinguish the new species from P. commersoniana are the glabrous posterior sepals and the slightly broader leaves. The new species is known from only three localities, all in natural high-elevation grasslands in Paraná and Santa Catarina states, southern Brazil. According to the IUCN criteria new species should be assessed as Endangered (EN). We present field photographs of P. campestris and related species, and we provide an identification key to the species previously included within the circumscription of P. commersoniana.

Chemical Composition and Bioactive Characterisation of Impatiens walleriana

The attractive colour characteristics of the flowers of the species Impatiens walleriana have been arousing great interest in the food industry, which is looking for potential natural sources of colouring ingredients. In this sense, the present work focused on the chemical and bioactive characterization of pink and orange flowers of I. walleriana. The phenolic compounds were determined by HPLC-DAD-ESI/MS; in addition, different bioactivities (antioxidant, antimicrobial, anti-inflammatory and cytotoxicity) were also analysed. Both samples studied showed significant amounts of phenolic compounds, especially phenolic acids, flavonoids, and anthocyanins, which justifies the excellent performance in the different bioactivities studied. The orange variety, despite having a greater variety of phenolic compounds, showed a total amount of compounds lower than the pink variety. Overall, the flowers of I. walleriana emerge as a promising resource to be explored by the food industry.

Assessing Specialized Metabolite Diversity in the Cosmopolitan Plant Genus Euphorbia L

Coevolutionary theory suggests that an arms race between plants and herbivores yields increased plant specialized metabolite diversity and the geographic mosaic theory of coevolution predicts that coevolutionary interactions vary across geographic scales. Consequently, plant specialized metabolite diversity is expected to be highest in coevolutionary hotspots, geographic regions, which exhibit strong reciprocal selection on the interacting species. Despite being well-established theoretical frameworks, technical limitations have precluded rigorous hypothesis testing. Here we aim at understanding how geographic separation over evolutionary time may have impacted chemical differentiation in the cosmopolitan plant genus Euphorbia. We use a combination of state-of-the-art computational mass spectral metabolomics tools together with cell-based high-throughput immunomodulatory testing. Our results show significant differences in specialized metabolite diversity across geographically separated phylogenetic clades. Chemical structural diversity of the highly toxic Euphorbia diterpenoids is significantly reduced in species native to the Americas, compared to Afro-Eurasia. The localization of these compounds to young stems and roots suggest a possible ecological relevance in herbivory defense. This is further supported by reduced immunomodulatory activity in the American subclade as well as herbivore distribution patterns. We conclude that computational mass spectrometric metabolomics coupled with relevant ecological data provide a strong tool for exploring plant specialized metabolite diversity in a chemo-evolutionary framework.

Ancestral range reconstruction of remote oceanic island species of Plantago (Plantaginaceae) reveals differing scales and modes of dispersal

AIM

The aim of this study was to resolve the phylogenetic placement of island taxa, reconstruct ancestral origins and resolve competing hypotheses of dispersal patterns and biogeographical histories for oceanic island endemic taxa within subgenus Plantago (Plantaginaceae).

LOCATION

Juan Fernández Islands, the Auckland Islands, Lord Howe Island, New Amsterdam Island, New Zealand, Tasmania, Falkland Islands, Rapa Iti and the Hawaiian Islands.

TAXON

Island endemics within Plantago (Plantaginaceae), a globally distributed taxonomic group comprising approximately 250 species.

METHODS

We use Bayesian phylogenetic and divergence time analyses and historical biogeographical analysis of molecular sequence data to infer the ancestral origins of the oceanic island species in Plantago.

RESULTS

Taxa within subgenus Plantago form clades based on geographic proximities and challenge previous phylogenetic relationships and classification based on morphology. We infer that biogeographic histories of oceanic island taxa from multiple islands were shaped by dispersal at different scales and possibly by different types of birds. The highly remote Hawaiian Islands and Rapa Iti were colonized from North American taxa in a pattern corresponding to known migration routes of large marine birds, rather than from New Zealand as previously hypothesized. The island endemics of Juan Fernández, the Falkland Islands, Lord Howe, Auckland Islands and New Zealand are found to have sources in the nearest continental areas. The analyses confirm recent speciation within subgenus Plantago - which is particularly heightened in island lineages in Hawaii and Rapa Iti - but show slightly older divergence times than previous molecular dating studies.

MAIN CONCLUSIONS

Using molecular data to infer ancestral ranges for plants with uncertain taxonomic relationships can greatly improve our understanding of biogeographical histories and help elucidate origins, dispersal modes and routes in widespread lineages with complex distribution patterns such as Plantago. We improve understanding of important floristic exchange areas between continents and islands as a result of long-distance dispersal. We infer that a combination of both stepping stone dispersal and extreme long-distance dispersal can shape insular floras, and that multiple floristic areas can be the sources of closely related island taxa. However, despite the successful dispersal of Plantago, radiation in island archipelagos is generally limited suggesting specific traits may limit diversification.

Toxicological evaluation of a standardized hydroethanolic extract from leaves of Plantago australis and its major compound, verbascoside

ETHNOPHARMACOLOGICAL RELEVANCE

Plantago australis is a perennial plant widely distributed in Latin America, and its seeds and leaves are used in folk medicine to treat many diseases and conditions. Among its various chemical compounds, verbascoside is one of the most present, and has several pharmacological activities described, but there is not much information about its toxicity.

AIMS OF THE STUDY

The aims of this study were to optimize the extraction of verbascoside from P. australis leaves with ultrasound methods, to develop a validated HPLC method to quantify verbascoside, and to evaluate the toxicological safety of the extract and verbascoside using in vitro and in vivo assays.

MATERIALS AND METHODS

Dried leaves of P. australis were submitted to different extraction methods (percolation and ultrasound). The optimization of the ultrasound extraction was carried out by complete factorial design (2²) and response surface methodology (RSM), followed by HPLC analysis for marker compounds. HPLC analysis was performed to verify the presence of the marker compounds aucubin, baicalein, oleanolic acid, ursolic acid and verbascoside. Mutagenicity was assessed by Salmonella/microsome mutagenicity assay. Cytotoxicity and genotoxicity were evaluated in V79 cells by reduction of tetrazolium salt (MTT) and neutral red uptake (NRU) assays, and alkaline comet assay, respectively. Verbascoside phototoxicity was assessed in 3T3 cells by the NRU phototoxicity assay. Wistar rats were used to perform the acute and sub-chronic toxicity tests.

RESULTS

Among the marker compounds, only verbascoside was found in the hydroethanolic extract of P. australis leaves (PAHE); its highest concentration was obtained with the ultrasound-assisted extraction (UAE) method, optimized in 40 min and 25 °C, and the method validation was successfully applied. Neither PAHE nor verbascoside showed mutagenic or genotoxic activities. Cytotoxicity assays demonstrated that both PAHE and verbascoside reduced cell viability only at the highest concentrations, and verbascoside had no phototoxic properties. The in vivo toxicity evaluation of PAHE suggested that the LD50 is higher than 5000 mg/Kg, indicating that this extract is safe for use. In addition, no signs of toxicity were found in subchronic exposure.

CONCLUSION

The HPLC method to quantify verbascoside was validated, and the extraction of verbascoside from P. australis leaves through ultrasound method was optimized, yielding an extract with 6% verbascoside. Our results suggest the toxicological safety of PAHE and verbascoside, corroborating the use of P. australis in folk medicine, and also indicate verbascoside as a potential ingredient in topical formulations.

The correct typification of Tradescantia crassula (Commelinaceae)

Here, we present evidence that the alleged correction of the typification of Tradescantia crassula recently proposed by Pellegrini, Forzza and Sakuragui is erroneous. Furthermore, we clarify misconceptions concerning the epitype of T. crassula, the specimen B-100521014, which was collected by Friedrich Sello in southern Brazil, and is not original material for T. crassula.

First record of the invasive species Rottboellia cochinchinensis (Poaceae, Andropogoneae) in the South Region of Brazil

Rottboellia cochinchinensis is an aggressive invasive species native to Asia. This species is known worldwide for invading crops and disturbed habitats in tropical and subtropical regions. In Brazil, R. cochinchinensis had its southernmost record in São Paulo state; however, in this study we expand its distribution to Santa Catarina state, in the South Region of Brazil, based on the discovery of a population in Blumenau municipality. These new records are ca. 440 km distant from the nearest known population, in São Paulo municipality, São Paulo state, Brazil.

Yet another new species from one of the best-studied neotropical areas: Plantago humboldtiana (Plantaginaceae), an extremely narrow endemic new species from a waterfall in southern Brazil

This article presents and describes Plantago humboldtiana, an extremely narrow endemic rheophytic new species from a waterfall in Corupá, Santa Catarina state, southern Brazil. The new species is unique in presenting a combination of type-G antrorse trichomes on scapes, pendulous inflorescences and 1-seeded pyxidia. Only one population is known to exist, despite intensive search efforts in nearby, similar environments. Its conservation status is assessed as critically endangered (CR) as the only known population is restricted to a dramatically small area, and is subject to extreme fluctuation due to occasional floods, and also to intense visitation by tourists, which can disturb its fragile habitat. We also present an updated identification key to the species of Plantago that occur in Santa Catarina. The recent description of three narrow endemic, threatened new species of Plantago in Santa Catarina, which is the Brazilian state with its flora best studied, highlights the need for more taxonomic research, especially in the neotropics.

First record of Plantago commersoniana (Plantaginaceae), a rare and threatened species, in the Central-West region of Brazil

Plantago commersoniana is a rare and threatened species, with a highly disjunct distribution, mainly in southern Brazil. This study expands its distribution to Mato Grosso do Sul state, in the Central-West region of Brazil, due to the discovery of a collection of this species from rocky grasslands in Ponta Porã. This new record is ca. 285 km distant from the nearest known population, in Yhú, Caaguazú department, eastern Paraguay. This is also the first record of a native Plantago species in Mato Grosso do Sul. Its conservation status according to the IUCN criteria is Endangered (EN).

First records of Landoltia punctata (G.Mey.) Les & D.J.Crawford (Araceae, Lemnoideae) in Santa Catarina, southern Brazil

Landoltia punctata (G.Mey.) Les & D.J. Crawford is a cosmopolite duckweed species of significant economic and technological interest, which in the Americas had its southernmost occurrence recorded in Pontal do Paraná, Paraná state, southern Brazil. This work extends its distribution southwards to Santa Catarina state, representing a range extension of ca. 300 km.

Clarifying the occurrence and conservation status of Plantago dielsiana Pilg. and P. australis Lam. subsp. pretoana Rahn (Plantaginaceae) in Brazil

Problems in the original description of a species can have long-lasting consequences. This is the case of Plantago dielsiana and P. australis subsp. pretoana, two taxa referred to occur in Brazil by different authors. This work has the objective of clarifying the long standing misunderstanding about the occurrence of these two taxa in Brazil. Additionally, we revise the distribution and assess the conservation status of P. australis subsp. pretoana, an endangered, rather poorly understood subspecies endemic to southeastern Brazil.

Growing knowledge: an overview of Seed Plant diversity in Brazil

Abstract An updated inventory of Brazilian seed plants is presented and offers important insights into the country's biodiversity. This work started in 2010, with the publication of the Plants and Fungi Catalogue, and has been updated since by more than 430 specialists working online. Brazil is home to 32,086 native Angiosperms and 23 native Gymnosperms, showing an increase of 3% in its species richness in relation to 2010. The Amazon Rainforest is the richest Brazilian biome for Gymnosperms, while the Atlantic Rainforest is the richest one for Angiosperms. There was a considerable increment in the number of species and endemism rates for biomes, except for the Amazon that showed a decrease of 2.5% of recorded endemics. However, well over half of Brazillian seed plant species (57.4%) is endemic to this territory. The proportion of life-forms varies among different biomes: trees are more expressive in the Amazon and Atlantic Rainforest biomes while herbs predominate in the Pampa, and lianas are more expressive in the Amazon, Atlantic Rainforest, and Pantanal. This compilation serves not only to quantify Brazilian biodiversity, but also to highlight areas where there information is lacking and to provide a framework for the challenge faced in conserving Brazil's unique and diverse flora.

First records of Melilotus albus Medik. (Fabaceae, Faboideae) in Santa Catarina, southern Brazil

Melilotus albus Medik. is a cosmopolite and invasive species, native to the Old World, which in Brazil had its occurrence hitherto recorded only in the states of São Paulo, Paraná and Rio Grande do Sul. This study extends its distribution to Santa Catarina state, southern Brazil, due to the recent discovery of populations in the municipalities of Florianópolis and Xanxerê. These new records are ca. 250 km distant from the nearest records, in Paraná state, also in southern Brazil.