BackgroundEpigenetic modifications, such as cytosine methylation, are inherited in plant species and may occur in response to biotic or abiotic stress, affecting gene expression without changing genome sequence. Laguncularia racemosa, a mangrove species, occurs in naturally contrasting habitats where it is subjected daily to salinity and nutrient variations leading to morphological differences. This work aims at unraveling how CpG-methylation variation is distributed among individuals from two nearby habitats, at a riverside (RS) or near a salt marsh (SM), with different environmental pressures and how this variation is correlated with the observed morphological variation.Principal FindingsSignificant differences were observed in morphological traits such as tree height, tree diameter, leaf width and leaf area between plants from RS and SM locations, resulting in smaller plants and smaller leaf size in SM plants. Methyl-Sensitive Amplified Polymorphism (MSAP) was used to assess genetic and epigenetic (CpG-methylation) variation in L. racemosa genomes from these populations. SM plants were hypomethylated (14.6% of loci had methylated samples) in comparison to RS (32.1% of loci had methylated samples). Within-population diversity was significantly greater for epigenetic than genetic data in both locations, but SM also had less epigenetic diversity than RS. Frequency-based (GST) and multivariate (βST) methods that estimate population structure showed significantly greater differentiation among locations for epigenetic than genetic data. Co-Inertia analysis, exploring jointly the genetic and epigenetic data, showed that individuals with similar genetic profiles presented divergent epigenetic profiles that were characteristic of the population in a particular environment, suggesting that CpG-methylation changes may be associated with environmental heterogeneity.ConclusionsIn spite of significant morphological dissimilarities, individuals of L. racemosa from salt marsh and riverside presented little genetic but abundant DNA methylation differentiation, suggesting that epigenetic variation in natural plant populations has an important role in helping individuals to cope with different environments.

In Brazil most of the effort for the conservation of plant species has comprised evaluation of taxa for the Lista Oficial das Espécies Ameaçadas de Extinção da Flora Brasileira (Official Threatened Flora Species List), and little has been done to conserve individual species. This is a result of the listing process being interpreted as the final goal rather than as a means to achieve conservation effectiveness. In addition, a variety of systems for the classification of extinction risk have been applied, resulting in an inaccurate view of the conservation status of the flora of the country. Here we review the national listing process to highlight the strengths and weaknesses of the Official Threatened Flora Species List. We used all available information to compile a list of taxa officially recorded as threatened in Brazil. The list was revised using the Flora do Brasil database. The resulting list has 4,967 taxa in 1,235 genera and 232 families. Despite controversies about advances in the Red Listing process, several improvements have been made at the institutional level, such as: (1) improving conservation databases, (2) developing information systems, and (3) increasing the number of taxonomists working in conservation biology. However, there is still no classification system for extinction risk that facilitates standardization of the listing process at the national level. In addition, regulatory processes related to the conservation of threatened plant species are not up-todate with the conceptual and methodological advances made by the scientific community. We conclude that adjustments are needed to ensure the effectiveness of the conservation of plant species in Brazil.

Mangrove is an ecosystem subjected to tide, salinity and nutrient variations. These conditions are stressful to most plants, except to mangrove plants that are well-adapted. However, many mangrove areas have extremely stressful conditions, such as salt marshes, and the plants nearby usually present morphological alterations. In Sepetiba Bay, two species of mangrove plants, Avicennia schaueriana and Laguncularia racemosa, have poor development near a salt marsh (SM) compared to plants at the riverside (RS), which is considered a favorable habitat in mangroves. The level of genetic diversity and its possible correlation with the morphological divergence of SM and RS plants of both species were assessed by AFLP molecular markers. We found moderate genetic differentiation between A. schaueriana plants from SM and RS areas and depleted genetic diversity on SM plants. On the other hand, Laguncularia racemosa plants had no genetic differentiation between areas. It is possible that a limited gene flow among the studied areas might be acting more intensely on A. schaueriana plants, resulting in the observed genetic differentiation. The populations of Laguncularia racemosa appear to be well connected, as genetic differentiation was not significant between the SM and RS populations. Gene flow and genetic drift are acting on neutral genetic diversity of these two mangrove species in the studied areas, and the observed

Over the last few decades botanic gardens worldwide have been encouraged to adopt complementary measures for the conservation of plant species from their own regions, combining in situ conservation efforts with ex situ methods, both in cultivation and in storage. This integrated approach is particularly important for botanic gardens in the tropics, which face the challenge of conserving a highly diverse and often threatened flora. We gathered information on the occurrence of threatened species in the natural vegetation reserves of 21 Brazilian botanic gardens. The data were collected from herbarium records in the database of the National Centre for Flora Conservation, and from the available plant inventories of these reserves. The results indicate that 148 species from the List of Threatened Species of Brazilian Flora are recorded as having been collected in the reserves. Of these, 51 species were maintained in the living collections of 18 botanic gardens and 83 species were recorded in federally protected areas. The occurrence of threatened species in the reserves of botanic gardens highlights the scientific value of these areas, as well as their biological, social and cultural importance for conservation. The results may be used to inform the planning of integrated conservation strategies for threatened species.

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