Early development of Moniliophthora perniciosa basidiomata and developmentally regulated genes

<p>Abstract</p> <p>Background</p> <p>The hemibiotrophic fungus <it>Moniliophthora perniciosa </it>is the causal agent of Witches' broom, a disease of <it>Theobroma cacao</it>. The pathogen life cycle ends with the production of basidiocarps in dead tissues of the infected host. This structure generates millions of basidiospores that reinfect young tissues of the same or other plants. A deeper understanding of the mechanisms underlying the sexual phase of this fungus may help develop chemical, biological or genetic strategies to control the disease.</p> <p>Results</p> <p>Mycelium was morphologically analyzed prior to emergence of basidiomata by stereomicroscopy, light microscopy and scanning electron microscopy. The morphological changes in the mycelium before fructification show a pattern similar to other members of the order <it>Agaricales</it>. Changes and appearance of hyphae forming a surface layer by fusion were correlated with primordia emergence. The stages of hyphal nodules, aggregation, initial primordium and differentiated primordium were detected. The morphological analysis also allowed conclusions on morphogenetic aspects. To analyze the genes involved in basidiomata development, the expression of some selected EST genes from a non-normalized cDNA library, representative of the fruiting stage <it>of M. perniciosa</it>, was evaluated. A macroarray analysis was performed with 192 selected clones and hybridized with two distinct RNA pools extracted from mycelium in different phases of basidiomata formation. This analysis showed two groups of up and down-regulated genes in primordial phases of mycelia. Hydrophobin coding, glucose transporter, Rho-GEF, Rheb, extensin precursor and cytochrome p450 monooxygenase genes were grouped among the up-regulated. In the down-regulated group relevant genes clustered coding calmodulin, lanosterol 14 alpha demethylase and PIM1. In addition, 12 genes with more detailed expression profiles were analyzed by RT-qPCR. One aegerolysin gene had a peak of expression in mycelium with primordia and a second in basidiomata, confirming their distinctiveness. The number of transcripts of the gene for plerototolysin B increased in reddish-pink mycelium and indicated an activation of the initial basidiomata production even at this culturing stage. Expression of the glucose transporter gene increased in mycelium after the stress, coinciding with a decrease of adenylate cyclase gene transcription. This indicated that nutrient uptake can be an important signal to trigger fruiting in this fungus.</p> <p>Conclusion</p> <p>The identification of genes with increased expression in this phase of the life cycle of <it>M. perniciosa </it>opens up new possibilities of controlling fungus spread as well as of genetic studies of biological processes that lead to basidiomycete fruiting. This is the first comparative morphologic study of the early development both <it>in vivo </it>and <it>in vitro </it>of <it>M. perniciosa </it>basidiomata and the first description of genes expressed at this stage of the fungal life cycle.</p

Physiological analyses of Genipa americana L. reveals a tree with ability as phytostabilizer and rhizofilterer of chromium ions for phytoremediation of polluted watersheds

International audienceGenipa americana L. is a tree that tolerates soil flooding and high levels of Cr3+, therefore it can be used in recomposition of ciliary forests at chromium-polluted watersheds. In this study, the ability of G. americana to phytoremediate the two major ionic Cr forms was assessed through Cr3+ and Cr6+ speciation, leaf gas exchange, growth and chemical composition of seedlings under Cr3+ and Cr6+ treatments. In greenhouse experiment, 4-month old seedlings were transferred to nutrient solution and, after three months, were submitted to 15 and 30 mg L−1 of each ionic Cr form. After 15-days, leaf gas exchanges were measured and seedlings were sampled for evaluation of growth and chemical composition. Results showed that Cr6+ is fully converted into Cr3+ inside the plant; the absorption of Cr3+ and Cr6+ interfered with the absorption kinetics of Zn, Cu, Fe, K, Mg, Ca and P; increments in nutrient solution of Cr6+ decreased root biomass and of both forms decreased shoot biomass; both Cr ions increased leaf area; mainly the exposure to Cr6+ form decreased net photosynthesis per unit leaf area, stomatal conductance to water vapor and leaf transpiration; and Cr highly accumulated in roots only as Cr3+, independently from the ionic form applied to seedlings. Hence, although exposure to Cr3+ and Cr6+ affected growth and development of G. americana seedlings, this woody species demonstrated a relevant capacity for phytoremediation of chromium, by phytostabilizing Cr6+ and rhizofiltering Cr3+

Lippia alba morphotypes cidreira and melissa exhibit significant differences in leaf characteristics and essential oil profile

Lippia alba (Mill.) N.E. Br. ex Britton & P. Wilson, Verbenaceae, is widely used in traditional Brazilian medicine for the treatment of abdominal distress. The species exhibits considerable chemical and morphological diversity, and various chemotypes have been characterized. A comparative study of L. alba, has been carried out of the morphoanatomical characteristics of the leaves and the profiles of the essential oils of the morphotypes cidreira and melissa grown in the Medicinal Plant Garden of the Universidade Estadual de Santa Cruz, Ilhéus, Bahia, Brazil. The mean plant height of cidreira was 1.80 m and the stems and branches were fairly erect, while melissa plants were smaller (1.60 m) and presented prostrate stems and branches. Although the leaf of the morphotypes look were similar, the mean values of length, width and area of the leaves of cidreira (respectively, 7.42 cm, 3.32 cm and 17.31 cm²) differed significantly from those of melissa (4.68 cm, 2.35 cm and 7.32 cm2). The morphotypes presented amphistomatic leaves with uniseriate epidermis on both surfaces. The mesophyll was dorsiventral, but in cidreira the palisade parenchyma was biseriate while in melissa it was uniseriate. Simple tector and capitate glandular trichomes were present on the adaxial and abaxial surfaces of the leaf blades of both morphotypes. Six distinct types of glandular trichomes could be distinguished: types I and II were present in both morphotypes, while type III was detected only in cidreira, and types IV to VI were present only in melissa. The two morphotypes also differed with respect to the composition of the essential oil, cidreira produced oil composed mainly of citral, while the oil from melissa was rich in citral, limonene and carvone

Light intensity on growth, leaf micromorphology and essential oil production of Ocimum gratissimum

Light conditions can promote the growth and development of plants and contribute to increase the essential oil production of commercially cultivated medicinal and aromatic species. In view of the great importance of Ocimum gratissimum L., Lamiaceae, as an aromatic plant, the objective of this work was to determine the effect of light intensities (approximately 4, 7, 11 and 20 mol m-2 d-1) on growth, foliar micromorphology, essential oil content, yield and chemical composition of O. gratissimum. Biomass production of different organs, root:shoot ratio and leaf mass per area were found to linearly increase with increased light availability, whereas stem dry matter fraction, number of leaves, leaf area and plant height have increased up to 10 mol m-2 d-1 and decreased from this value. The tector trichomes density increased with increased light availability, but there was no effect of light treatments on the glandular trichomes density and essential oil content. Regardless of the light level, the major component of the essential oil was eugenol. The essential oil yield per plant increased linearly with light intensity as a direct effect of increased leaf biomass under similar conditions

Erratum to: Meristematic activity of the endodermis and the pericycle in the primary thickening in monocotyledons. Considerations on the "PTM" [An Acad Bras Cienc 77(2005): 259-274]

This paper proposes a new interpretation for primary thickening in monocotyledons. The anatomy of the vegetative organs of the following species was examined: Cephalostemon riedelianus (Rapataceae), Cyperus papyrus (Cyperaceae), Lagenocarpus rigidus, L. junciformis (Cyperaceae), Echinodorus paniculatus (Alismataceae) and Zingiber officinale (Zingiberaceae). The endodermis with meristematic activity was observed in the root of all the species, in the stem of Cyperus, Cephalostemum and Lagenocarpus rigidus, and in the leaf trace of Cyperus and leaf of Echinodorus. Considering the continuity of tissues through the root, stem and leaf, the authors conclude that in the stem the pericycle remains active throughout the life of the plant as the generator of the vascular tissue. The "Primary Thickening Meristem" is in fact the pericycle plus the endodermis and its derivatives (or only the pericycle). Close to the stem apex, the assemblage of seems to be a unique meristem, giving rise to the inner cortex and vascular tissues.A proposta deste trabalho é mostrar uma nova interpretação do meristema de espessamento primário em monocotiledôneas. Anatomia dos órgãos vegetativos das seguintes espécies foi examinada: Cephalostemon riedelianus (Rapataceae), Cyperus papyrus (Cyperaceae), Lagenocarpus rigidus, L. Junciformis (Cyperaceae), Echinodorus paniculatus (Alismataceae) and Zingiberofficinale (Zingiberaceae). A atividade meristemática da endoderme foi observada nas raizes de todas as espécies, no caule de Cyperus, Cephalostemum e Lagenocarpus rigidus, e no traço foliar de Cyperus e folha de Echinodorus. Considerando a continuidade dos tecidos através da raiz, caule e folha, as autoras concluem que no caule o periciclo permanece ativo durante a vida da planta, como um gerador de tecidos vasculares. O "Meristema de Espessamento Primário" é o periciclo em fase meristemática, juntamente com a endoderme e suas derivadas (ou apenas o periciclo). Próximo ao ápice caulinar, esses tecidos se assemelham a um único meristema, dando origem ao córtex interno e aos tecidos vasculares

Adsorptive properties of highly porous activated carbon from açaí (Euterpe oleracea) towards the toxic herbicide atrazine

The great variety and possibilities of consumption of açaí pulp (Euterpe oleracea) have made its consumption increase considerably in recent years, mainly in Brazilian territory. The big problem is the generation of tons of waste that characterizes the fruit stone. This waste was converted into a highly porous activated carbon and employed to remove the herbicide atrazine. The characterization analyses confirmed that the applied methodology generated an adsorbent with good textural characteristics (specific surface area 920.56 m² g−1, pore volume 0.467 cm3 g−1; average pore diameter 1.13 nm). Furthermore, it was found that the adsorption of atrazine reached satisfactory results at natural pH and with an adsorbent mass of 0.54 g for each liter of solution. The Redlich-Peterson model presented the most satisfactory fit with the equilibrium data. This study found that the evolution of system temperature increased the concentration in the solid phase of 178 mg g−1 at 328 K. Regarding adsorption kinetics, the linear driving force model can represent the experimental data. Also, the predicted adsorption data of the model follows the experimental data. The application of the adsorbent in the removal of the herbicide mixture presented an efficiency of 81.45%. Therefore, using residual açaí fruit seeds as biomass for producing activated carbon employing zinc chloride as an agent activator is the possible application of the material. The material showed high efficiency and affinity with the target molecule

Anatomical analysis of leaf cross-sections of WT and <i>CsGolS6-</i>overexpressing transgenic plants under control (irrigated) and drought stress conditions.

(A) Leaf cross-section of WT and CsGolS6-overexpressing transgenic (L3, L6 and L10) plants subjected to drought stress, as observed under photonic microscope. The mesophyll region is shown. Magnification bars represent 100 μm. Adaxial side (adx), abaxial side (adx), palisade parenchyma (pp), spongy parenchyma (pe), glandular trichomes (tg), stomata (*), vascular tissue (arrow) and idioblasts (i). (B) Quantitative analysis of the leaf anatomy of WT and transgenic (L3, L6, L10 and L12) plants subjected to control (irrigated) and drought stress treatments. The data are means ± SE of three technical replicates, each containing three slides composed for each plant line. *Statistically significant differences between WT and transgenic plants by the Dunnett test at P ≤ 0.05.</p

Physiological analysis of WT and <i>CsGolS6-</i>overexpressing transgenic tobacco plants under different water regimes in greenhouse conditions.

WT and transgenic (L3-L12) plants were exposed to three water regimes: (i) control (leaf water potential at -0.3 a -0.5 MPa), (ii) drought (leaf water potential at -1.5 a -2.0 MPa) and (iii) rehydration (leaf water potential at -0.3 a -0.5 MPa after a cycle of drought stress). The data are means ± SE of ten biological replicates. *,**Significantly different from WT at the respective water treatment by the Dunnett test at P ≤ 0.05 or P ≤ 0.01, respectively.</p

In vitro stress tolerance assay of <i>CsGolS6</i>-overexpressing transgenic tobacco plants.

(A) Representative phenotypes of WT and CsGolS6-overexpressing transgenic (L3-12) lines grown under control, salt and PEG treatments for 20 days. (B) Seedling biomass of WT and transgenic lines under control, salt and PEG treatments for 20 days. The data are means ± SE of three technical replicates composed of fifteen seedlings for each line. *,**,***Significantly different from WT at the respective treatment by the Student’s t test at P ≤ 0.05, P ≤ 0.01 or P ≤ 0.001, respectively.</p

Phylogeny and expression of <i>C</i>. <i>sinensis GolS</i> (<i>CsGolS</i>) genes.

(A) Phylogenetic relationships of CsGolS amino acid sequences with those of Arabidopsis thaliana (At). (B) RNA-Seq data of CsGolS expression in the different C. sinensis tissues. RPKM: reads per kilobase per million mapped. (C-G) Expression analysis of CsGolS genes in response to drought (C, D) and salt (E, F) stresses and ‘Ca. L. asiaticus’ infection (G). Ratios (log2) of relative mRNA levels in leaves and roots between stressed and control plants of sweet orange (C-F) and in leaves between infected and control plants of rough lemon (RL) and sweet orange (SW) at 0, 7, 17, and 34 WAI (G), as measured by qPCR. GAPC2 was used as an endogenous control. Data are means ± SE from three biological replicates. *,**,***Significantly different from control treatment (C-F) or sweet orange at the respective WAI (G) by the Student’s t test at P ≤ 0.05, P ≤ 0.01 or P ≤ 0.001, respectively.</p