Alcantarea (Bromeliaceae) leaf anatomical characterization and its systematic implications

Alcantarea (Bromeliaceae) has 26 species that are endemic to eastern Brazil, occurring mainly on gneiss-granitic rock outcrops (`inselbergs`). Alcantarea has great ornamental potential and several species are cultivated in gardens. Limited data is available in the literature regarding the leaf anatomical features of the genus, though it has been shown that it may provide valuable information for characterizing of Bromeliaceae taxa. In the present work, we employed leaf anatomy to better characterize the genus and understand its radiation into harsh environments, such as inselbergs. We also searched for characteristics potentially useful in phylogenetic analyses and in delimiting Alcantarea and Vriesea. The anatomical features of the leaves, observed for various Alcantarea species, are in accordance with the general pattern shown by other Bromeliaceae members. However, some features are notable for their importance for sustaining life on rock outcrops, such as: small epidermal thick-walled cells, uneven sinuous epidermal walls, hypodermis often differentiated into lignified layers with thick-walled cells, aquiferous hypodermis bearing collapsible cells, and the presence of well developed epicuticular stratum. Alcantarea leaves tend to show different shapes in the spongy parenchyma, and have chlorenchymatous palisade parenchyma arranged in more well-defined arches, when compared to Vriesea species from the same habitat.FAPESPFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)CNPqConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Building an embryo: An auxin gene toolkit for zygotic and somatic embryogenesis in Brazilian pine

Many studies in the model species Arabidopsis thaliana characterized genes involved in embryo formation. However, much remains to be learned about the portfolio of genes that are involved in signal transduction and transcriptional regulation during plant embryo development in other species, particularly in an evolutionary context, especially considering that some genes involved in embryo patterning are not exclusive of land plants. This study, used a combination of domain architecture phylostratigraphy and phylogenetic reconstruction to investigate the evolutionary history of embryo patterning and auxin metabolism (EPAM) genes in Viridiplantae. This approach shed light on the co-optation of auxin metabolism and other molecular mechanisms that contributed to the radiation of land plants, and specifically to embryo formation. These results have potential to assist conservation programs, by directing the development of tools for obtaining somatic embryos. In this context, we employed this methodology with critically endangered and non-model species Araucaria angustifolia, the Brazilian pine, which is current focus of conservation efforts using somatic embryogenesis. So far, this approach had little success since somatic embryos fail to completely develop. By profiling the expression of genes that we identified as necessary for the emergence of land-plant embryos, we found striking differences between zygotic and somatic embryos that might explain the developmental arrest and be used to improve A. angustifolia somatic culture

The meristematic activity of the endodermis and the pericycle and its role in the primary thickening of stems in monocotyledonous plants

Background: It had long been thought that a lateral meristem, the so-called primary thickening meristem (PTM) was responsible for stem thickening in monocotyledons. Recent work has shown that primary thickening in the stems of monocotyledons is due to the meristematic activity of both the endodermis and the pericycle. Aims: The aim of this work is to answer a set of questions about the developmental anatomy of monocotyledonous plants: (1) Do the stem apices of monocots have a special meristematic tissue, the PTM? (2) Are the primary tissues of the stem the same as those of the root? (3) Is there good evidence for the formation of both the cortex and the vascular tissue from a single meristem, the PTM, in the shoot and from two distinguishable meristems in the root? (4) If the PTM forms only the cortex, what kind of meristem forms the vascular tissue? Methods: Light microscopy was used to examine stem and root anatomy in 16 species from 10 monocotyledonous families. Results: It was observed that radially aligned cortical cells extend outwards from endodermal initial cells in the cortex of the roots and the stems in all the species. The radial gradation in size observed indicates that the cortical cells are derivatives of a meristematic endodermis. In addition, perfect continuity was observed between the endodermis of the root and that of the stem. Meristematic activity in the pericycle gives rise to cauline vascular bundles composed of metaxylem and metaphloem. Conclusion: No evidence was obtained for the existence in monocotyledons of a PTM. Monocotyledons appear to resemble other vascular plants in this respect.Sao Paulo Research Foundation (FAPESP)Sao Paulo Research Foundation (FAPESP)National Council for Scientific and Technological Development (CNPq)National Council for Scientific and Technological Development (CNPq

A 3D model of the AaMps1 kinase domain.

<p>(A) An overview of the kinase domain. Rose: activation loop; Blue: DFG motif; and Cyan: threonines. (B) A detailed view of the DFG motif. (C) A detailed view of the threonine residues (T870, T871, and T881) that are related to autophosphorylation.</p

The morphology of <i>A</i>. <i>angustifolia</i> PEMs in cell suspension culture.

<p>Morphological features of PEMs after 15 days of incubation in MSG basic culture medium without (A) or with the Mps1 inhibitor SP600125 (10 μM) (B). EH = embryonal head; EC = embryogenic cells; SC = suspensor cells. Bars = 200 μm.</p

Quantification of the AaMps1 protein.

<p>Relative concentration (%) of AaMps1 protein by HDMS^E (data-independent acquisition, with ion mobility) mass spectrometry analysis in embryogenic suspension cultures of <i>A</i>. <i>angustifolia</i> before (0) and after 15 days of incubation in MSG basic culture medium with (10 μM) or without Mps1 inhibitor SP600125. Means followed by different letters are significantly different (<i>P</i> < 0.01) according to Tukey's test. (n = 3; Coefficient of variation = 14.1%).</p

Mass increment (g) in <i>A</i>. <i>angustifolia</i> embryogenic suspension cultures.

<p>(A) FM and (B) DM values in embryogenic suspension cultures before (0) and after 6, 15, 21, and 27 days of incubation in MSG basic culture medium with (10 μM) or without Mps1 inhibitor SP600125. Lowercase letters denote significant differences (<i>P</i> < 0.01) between treatments for each day of incubation. Capital letters denote significant differences (<i>P</i> < 0.01) in the same treatment during incubation. Means followed by different letters are significantly different (<i>P</i> < 0.01) according to Tukey's test. CV = coefficient of variation (n = 6; CV FM = 10.3%; CV DM = 7.3%).</p

AaMps1 protein identification.

<p>AaMps1 protein identification.</p

Phenogram of Mps1.

<p>Sequence data details are listed in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0153528#pone.0153528.s004" target="_blank">S1 Table</a>. The topology of the tree was consistent with the phylogenetic distribution of the species. Mps1 is encoded by a single-copy gene in monocotyledons and <i>Araucaria angustifolia</i>. Paralogs were found in some species inside the Eudicotyledons clade, indicating species-specific duplications. The bootstrap values are shown on the branches. The tree was rooted with MAPKs of <i>Arabidopsis thaliana</i> as the outgroup. <i>Amborella trichopoda</i> (Ab), <i>Aquilegia coerulea</i> (Ac), <i>Arabidopsis lyrata</i> (Al), <i>Arabidopsis thaliana</i> (At), <i>Araucaria angustifolia</i> (Aa), <i>Boechera stricta</i> (Bs), <i>Brachypodium distachyon</i> (Bd), <i>Brassica rapa</i> (Br), <i>Capsella grandiflora</i> (Cg), <i>Capsella rubella</i> (Cr), <i>Carica papaya</i> (Cp), <i>Citrus clementina</i> (Cc), <i>Cucumis sativus</i> (Cs), <i>Eucalyptus grandis</i> (Eg), <i>Eutrema salsugineum</i> (Es), <i>Fragaria vesca</i> (Fv), <i>Glycine max</i> (Gm), <i>Gossypium raimondii</i> (Gr), <i>Linum usitatissimum</i> (Lu), <i>Malus domestica</i> (Md), <i>Manihot esculenta</i> (Me), <i>Medicago trunculata</i> (Mt), <i>Mimulus guttatus</i> (Mg), <i>Oryza sativa</i> (Os), <i>Panicum virgatum</i> (Pv), <i>Phaseolus vulgaris</i> (Phv), <i>Pinus pinaster</i> (Ppi), <i>Populus trichocarpa</i> (Pt), <i>Prunus persica</i> (Pp), <i>Ricinus communis</i> (Rc), <i>Salix purpurea</i> (Sp), <i>Solanum tuberosum</i> (St), <i>Sorghum bicolor</i> (Sb), <i>Theobroma cacao</i> (Tc), <i>Vitis vinifera</i> (Vv), and <i>Zea mays</i> (Zm).</p

Phosphorylation sites of the kinase domain.

<p>Phosphorylation sites of the kinase domain.</p