Alkaloids (emetine and cephalin) production - affected by full sunlight stress in Carapichea ipecacuanha.

This study evaluated the responses of Carapichea ipecacuanha to sunlight stress-induced changes in the electron transport chain and its extended effects on alkaloid production (emetine and cephalin). The treatments consisted of: (i). 50, 70, and 90% shading (controls) and their respective exposure to full sunlight; besides, full sunlight (55 days of direct sun exposure). Photosynthetic pigments, chlorophyll a fluorescence transient, antioxidant enzymatic system, and quantification of cephalin and emetine were analyzed. Several changes in the Chl a fluorescence induction were observed, such as a decline in the quantum yield of the conversion of photochemical energy and photosynthetic performance and; an increase in emetine production of plants exposed to full sunlight. These results demonstrated that ipecac plants are extremely sensitive to full exposure to solar radiation, especially in periods with high temperatures, such as in summer, however with increment in emetine production.

Potassium supply promotes the mitigation of NaCl-induced effects on leaf photochemistry, metabolism and morphology of Setaria viridis.

Soil salinity has the potential to severely affect crop performance. To maintain cell functioning and improve salt tolerance, the maintenance of K+ homeostasis is crucial in several plant metabolism processes. Besides, potassium fertilization can efficiently alleviate the perilous effects of salinity. We characterized impacts in Setaria viridis exposed to NaCl and KCl to underlying photochemistry mechanisms, K+ and Na+ shoot contents, enzymatic activity, electrolytic leakage, and morphological responses focusing on non-stomatal limitation of photosynthesis. Plants were exposed to sodium chloride (NaCl; 0, 150 and 250 mM) and potassium chloride (KCl; 0, 5, 9 mM). The exposure to NaCl affected S. viridis leaves morphological and physiologically. Plants submitted to 150 mM showed reductions in performance indexes (PIabs and PItotal; JIP-test), and the presence of positive K- and L-bands. Plants exposed to 250 mM exhibited blockage in electron flow further than QA within 48h and permanent photoinhibition at 96 h. The presence of 9 and 5 mM of KCl counteracted the effects of NaCl on plants submitted to 150 mM, concomitant with increases in K+ accumulation and cell turgidity conservation, causing positive effects in plant growth and metabolism. Neither KCl concentrations were effective in reducing NaCl-induced effects on plants exposed to 250 mM of NaCl. Our results support the conclusion that greater availability of K+ alleviates the harmful effects of salinity in S. viridis under moderate stress and that application of KCl as means of lightning saline stress has a concentration and a salt level limit that must be experimentally determined.

Physiological and molecular responses of Setaria viridis to osmotic stress.

Drought-tolerant species, such as Setaria viridis, a C4 model plant, make physiological and biochemical adjustments water limitation and recover from the stress upon its release. We investigated S. viridis (A10.1 accession) responses to continuing osmotic stress. The osmotic stress was imposed using polyethylene glycol (PEG) 8000 (7.5%) for 10 days. Morphological traits and stomatal conductance were measured daily for the 10 days. On days 6 and 10, the following traits were measured separately for root and shoot: relative water content (RWC), osmotic potential (OP), electrolytic leakage (EL), and proline content. qPCR analysis was used to evaluate the expression of five selected genes in roots (SvLEA, SvDREB1C, SvPIP2-1, SvHSP20, and SvP5CS2), and chlorophyll a fluorescence was measured on three key days. The morphological data demonstrated a drastic reduction in shoot biomass as an effect of water deficit caused by the osmotic stress. Shoot biomass reduction could be associated with putative ABA-dependent signaling involved in SvDREB1C expression. Stomatal conductance and photosynthesis were severely affected up until day 6, however, stomatal conductance and some photosynthetic parameters such as FV/FM, ABS/RC, and DI0/RC showed total or slight recovery on day 10. Root EL decreased in treated plants suggesting an investment in membrane protection by osmoregulator expression such as dehydrin (SvLEA) and proline (SvP5CS2) genes. Our data suggest that S. viridis exhibited a partial recovery from an imposed and constant osmotic stress within 10 days.

Petroleum contamination and bioaugmentation in bacterial rhizosphere communities from Avicennia schaueriana

ABSTRACT Anthropogenic activity, such as accidental oil spills, are typical sources of urban mangrove pollution that may affect mangrove bacterial communities as well as their mobile genetic elements. To evaluate remediation strategies, we followed over the time the effects of a petroleum hydrocarbon degrading consortium inoculated on mangrove tree Avicennia schaueriana against artificial petroleum contamination in a phytoremediation greenhouse experiment. Interestingly, despite plant protection due to the inoculation, denaturing gradient gel electrophoresis of the bacterial 16S rRNA gene fragments amplified from the total community DNA indicated that the different treatments did not significantly affect the bacterial community composition. However, while the bacterial community was rather stable, pronounced shifts were observed in the abundance of bacteria carrying plasmids. A PCR-Southern blot hybridization analysis indicated an increase in the abundance of IncP-9 catabolic plasmids. Denaturing gradient gel electrophoresis of naphthalene dioxygenase (ndo) genes amplified from cDNA (RNA) indicated the dominance of a specific ndo gene in the inoculated petroleum amendment treatment. The petroleum hydrocarbon degrading consortium characterization indicated the prevalence of bacteria assigned to Pseudomonas spp., Comamonas spp. and Ochrobactrum spp. IncP-9 plasmids were detected for the first time in Comamonas sp. and Ochrobactrum spp., which is a novelty of this study.

Characterization of Laguncularia racemosa transcriptome and molecular response to oil pollution.

Mangroves are ecosystems of economic and ecological importance. Laguncularia racemosa (Combretaceae), popularly known as white mangrove, is a species that greatly contributes to the community structure of neotropical and West African mangrove forests. Despite the significance of these ecosystems, they have been destroyed by oil spills that can cause yellowing of leaves, increased sensitivity to other stresses and death of trees. However, the molecular response of plants to oil stress is poorly known. In this work, Illumina reads were de novo assembled into 46,944 transcripts of L. racemosa roots and leaves, including putative isoform variants. In addition to improving the genomic information available for mangroves, the L. racemosa assembled transcriptome allowed us to identify reference genes to normalize quantitative real-time PCR (qPCR) expression data from oil-stressed mangrove plants, which were used in RNASeq validation. The analysis of expression changes induced by the oil exposure revealed 310 and 286 responsive transcripts of leaves and roots, respectively, mainly up-regulated. Enriched GO categories related to chloroplasts and photosynthesis were found among both leaf and root oil-responsive transcripts, while "response to heat" and "response to hypoxia" were exclusively enriched in leaves and roots, respectively. The comparison of L. racemosa 12-h-oil-stressed leaf expression profile to previous Arabidopsis heat-stress studies and co-expression evidence also pointed to similarities between the heat and oil responses, in which the HSP-coding genes seem to play a key role. A subset of the L. racemosa oil-responsive root genes exhibited similar up-regulation profiles to their Arabidopsis homologs involved in hypoxia responses, including the HRA1 and LBD41 TF-coding genes. Genes linked to the ethylene pathway such as those coding for ERF TFs were also modulated during the L. racemosa root response to oil stress. Taken together, these results show that oil contamination affects photosynthesis, protein metabolism, hypoxia response and the ethylene pathway in L. racemosa 12-h-oil-exposed leaves and roots.

Petroleum contamination and bioaugmentation in bacterial rhizosphere communities from Avicennia schaueriana.

Anthropogenic activity, such as accidental oil spills, are typical sources of urban mangrove pollution that may affect mangrove bacterial communities as well as their mobile genetic elements. To evaluate remediation strategies, we followed over the time the effects of a petroleum hydrocarbon degrading consortium inoculated on mangrove tree Avicennia schaueriana against artificial petroleum contamination in a phytoremediation greenhouse experiment. Interestingly, despite plant protection due to the inoculation, denaturing gradient gel electrophoresis of the bacterial 16S rRNA gene fragments amplified from the total community DNA indicated that the different treatments did not significantly affect the bacterial community composition. However, while the bacterial community was rather stable, pronounced shifts were observed in the abundance of bacteria carrying plasmids. A PCR-Southern blot hybridization analysis indicated an increase in the abundance of IncP-9 catabolic plasmids. Denaturing gradient gel electrophoresis of naphthalene dioxygenase (ndo) genes amplified from cDNA (RNA) indicated the dominance of a specific ndo gene in the inoculated petroleum amendment treatment. The petroleum hydrocarbon degrading consortium characterization indicated the prevalence of bacteria assigned to Pseudomonas spp., Comamonas spp. and Ochrobactrum spp. IncP-9 plasmids were detected for the first time in Comamonas sp. and Ochrobactrum spp., which is a novelty of this study.

Anatomy and ultrastructure of embryonic leaves of the C4 species Setaria viridis.

Background and Aims: Setaria viridis is being promoted as a model C4 photosynthetic plant because it has a small genome (~515 Mb), a short life cycle (~60 d) and it can be transformed. Unlike other C4 grasses such as maize, however, there is very little information about how C4 leaf anatomy (Kranz anatomy) develops in S. viridis. As a foundation for future developmental genetic studies, we provide an anatomical and ultrastructural framework of early shoot development in S. viridis, focusing on the initiation of Kranz anatomy in seed leaves. Methods: Setaria viridis seeds were germinated and divided into five stages covering development from the dry seed (stage S0) to 36 h after germination (stage S4). Material at each of these stages was examined using conventional light, scanning and transmission electron microscopy. Key Results: Dry seeds contained three embryonic leaf primordia at different developmental stages (plastochron 1-3 primordia). The oldest (P3) leaf primordium possessed several procambial centres whereas P2 displayed only ground meristem. At the tip of P3 primordia at stage S4, C4 leaf anatomy typical of the malate dehydrogenase-dependent nicotinamide dinucleotide phosphate (NADP-ME) subtype was evident in that vascular bundles lacked a mestome layer and were surrounded by a single layer of bundle sheath cells that contained large, centrifugally located chloroplasts. Two to three mesophyll cells separated adjacent vascular bundles and one mesophyll cell layer on each of the abaxial and adaxial sides delimited vascular bundles from the epidermis. Conclusions: The morphological trajectory reported here provides a foundation for studies of gene regulation during early leaf development in S. viridis and a framework for comparative analyses with other C4 grasses.

Streptomyces odonnellii sp. nov., a proteolytic streptomycete isolated from soil under cerrado (savanna) vegetation cover.

A novel streptomycete, strain 594T, isolated from Brazilian soil collected under cerrado (savanna) vegetation cover is described. Strain 594T produced thermophilic chitinolytic proteases in assays containing feather meal and corn steep liquor as sole sources of carbon and nitrogen. The strain produced white to grey aerial mycelium and spiral chains of spiny-surfaced spores on the aerial mycelium and did not produce diffusible pigments. The ll-isomer of diaminopimelic acid was present in the cell wall and menaquinones were predominantly MK-9(H6) (52 %) and MK-9(H8) (30 %) with 6 % MK-9(H4) and slightly less than 1 % MK-9(H2). Polar lipids present were phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol and an unknown phospholipid. The major fatty acids were anteiso-C15 : 0, anteiso-C16 : 0, anteiso-C14 : 0 and anteiso-C17 : 0. The G+C content of the genomic DNA was 70.4 mol%. Phylogenetic analysis of the nearly complete 16S rRNA gene sequence indicated that it differed from described Streptomyces species. Multilocus sequence analysis (MLSA) using five housekeeping genes (atpD, gyrB, rpoB, recA and trpB) comparing Streptomyces type strains showed that the MLSA distance of strain 594T to the most closely related species was greater than the 0.007 threshold. The in silico DNA-DNA relatedness between the genome sequence of strain 594T and that of the phylogenetically nearest species was well below the species level recommendation. There was thus multiple evidence justifying the description of this strain as representing a novel species, for which the name Streptomyces odonnellii sp. nov. is proposed. The type strain is 594T (=IMPPG 594T=DSM 41949T=NRRL B-24891T).

Diagnosing the level of stress on a mangrove species (Laguncularia racemosa) contaminated with oil: A necessary step for monitoring mangrove ecosystems.

Monitoring the effects of pollution on mangrove vegetation is a challenge. A specific study using an oil spill simulation on mangrove species was conducted to address this challenge. We tested the effectiveness of the chlorophyll a fluorescence kinetics as a fast and robust method to diagnose the vitality of Laguncularia racemosa. We used L. racemosa plants contaminated with marine fuel oil in mangrove microcosm models. Several parameters of the JIP-test were capable of detecting the impairment of the photosynthetic function prior to the visual manifestation of symptoms in response to oil contamination. The results support the use of the chlorophyll fluorescence transient as a reliable, fast and easy to apply diagnostic method for evaluating oil-impacted mangroves. To the best of our knowledge, it is the first time that consistent data showing photosynthetic impairment in response to oil contamination is shown for a mangrove tree species.

Are sun- and shade-type anatomy required for the acclimation of Neoregelia cruenta?

Sun and shade plants are often discriminated by a number of sun- and shade-type anatomies. Nonetheless, we propose that among tank-bromeliads, changes in rosette architecture satisfy the requirements for coping with contrasting light levels. The tank-bromeliad Neoregelia cruenta naturally colonises sub-habitats ranging from full exposure to direct sunlight, to shaded environments in sand ridge plains. We quantified anatomical and morphological traits of leaves and rosettes of N. cruenta grown under sun and shade conditions. Cells with undulated lateral walls within the water parenchyma are for the first time described for the family. Under high light, leaf blades were wider, shorter, and yellowish. The rosette diameter of sun plants was less than half that of shade plants. Sun leaves overlapped with neighbouring leaves for most of their length, forming a cylindrical rosette where water accumulates. Shade leaves only overlapped in the centre of the rosette. Most anatomical traits were similar under both growth conditions. Stomata were absent from the base of sun leaves, which is probably explained by limited gas exchange at the base of the tight sun-type rosette. Data suggest that the ability of N. cruenta to acclimate to sun and shade is better explained by changes in rosette architecture than by leaf anatomy.

Physiological aspects of mangrove (Laguncularia racemosa) grown in microcosms with oil-degrading bacteria and oil contaminated sediment.

To assess the severity of oil spills on mangroves, diagnosis of the vegetation health is crucial. Some aspects of photosynthesis such as photochemical efficiency and leaf pigment composition together with the level of oxidative stress may constitute reliable indicators for vegetation health. To test this approach 14 month old Laguncularia racemosa were contaminated with 5 L m(-2) of the marine fuel oil MF-380 and treated with an oil degrading bacterial consortium in microcosms. Contamination resulted in a 20% decrease in shoot dry weight after 128 days. Photochemical efficiency, pigment content, catalase and ascorbate peroxidase remained unchanged. Multivariate ordination of DGGE microbial community fingerprints revealed a pronounced separation between the oil contaminated and the non-contaminated samples. Further studies are necessary before physiological parameters can be recommended as indicators for plant's health in oil polluted mangroves.

Characterization of the photosynthetic conditions and pigment profiles of the colour strains of Hypnea musciformis from field-collected and in vitro cultured samples

Hypnea musciformis (Wulfen) JV Lamour. is a species of great economic interest as it produces Κ-carrageenan and has shown biological activities against HIV and HSV viruses. This species displays different colour strains in its natural habitat, which may have implications for the biotechnological potential of the species. The aim of this study was to characterize the photosynthetic apparatus and pigment profile of three colour strains of H. musciformis (green, brown and red) in their natural habitat and in culture. Chlorophyll a fluorescence of photosystem II was measured with a pulse-amplitude modulated fluorometer and pigments were quantified by spectrofluorimetry (chlorophyll a) and spectrophotometry (phycobiliproteins). In the natural habitat, we detected significant differences between the colour strains for the following photochemical parameters: the green strain had a higher effective quantum yield (ΦPSII) than the red strain and a higher maximum relative electron transport rate (rETRmax) than the brown and red strains. Saturation irradiances were 1000 µE.m-2.s-1 (green) and 500 µE.m-2.s-1 (brown and red). Concerning in vitro culture, the green strain presented the lowest ΦPSII, rETRmax, and α rETR, while the brown strain presented the highest values for these same parameters. The chlorophyll a content of the cultured green strain was the lowest. The phycoerythrin contents of the three colour strains were unchanged by either natural of in vitro conditions: lower in green, intermediate in brown and higher in the red strain, ensuring the chromatic identity of the strains. Our results suggest that the green strain has a better performance when exposed to high irradiance, but a lower efficiency under low irradiance compared to the brown and red strains.

Influence of blue light on the leaf morphoanatomy of in vitro Kalanchoe pinnata (Lamarck) Persoon (Crassulaceae).

Kalanchoe pinnata (Lamarck) Persoon (Crassulaceae) (air plant, miracle leaf) is popularly used to treat gastrointestinal disorders and wounds. Recently, the species was tested to treat cutaneous leishmaniasis with successful results. This medicinal activity was associated with the phenolic fraction of the plant. Blue light induces biosynthesis of phenolic compounds and many changes in anatomical characteristics. We studied the effects of supplementary blue light on the leaf morphology of in vitro K. pinnata. Plants cultured under white light (W plants) only and white light plus blue light (WB plants) show petioles with plain-convex section, amphistomatic leaf blades with simple epidermis, homogeneous mesophyll with densely packed cells, and a single collateral vascular bundle in the midrib. W plants have longer branches, a larger number of nodes per branch, and smaller leaves, whereas WB plant leaves have a thicker upper epidermis and mesophyll. Leaf fresh weight and leaf dry weight were similar in both treatments. Phenolic idioblasts were observed in the plants supplemented with blue light, suggesting that blue light plays an important role in the biosynthesis of phenolic compounds in K. pinnata.

Urban ethnobotany in Petrópolis and Nova Friburgo (Rio de Janeiro, Brazil) / Etnobotânica urbana em Petrópolis e Nova Friburgo (Rio de Janeiro, Brasil)

The main goal of this paper was the study of the useful plants sold in the open-air fairs of Petrópolis and Nova Friburgo, Rio de Janeiro, Brazil. Data collection was obtained through participant observation, semi structured interviews and free listing with four herbalist informants. From the interviews, 115 species (belonging to 49 families) were recorded: 94 for medicinal purposes, 12 with religious application, and 9 for ornamental purposes. Thirty percent of the species were native, and 72 percent herbaceous. The most representative families were Asteraceae (26 species) and Lamiaceae (10 species). The medicinal species related to diseases of the respiratory system were more common during the winter and autumn. "Espinheira-santa" (Clarisia cf. ilicifolia) had the highest Relative Importance (1.8) and collocation in all seasons using the Preference Ranking, although its effectiveness or toxicity levels have not been established. The importance of the study is to gather knowledge from local herbalists about commercialized species in open-air fairs and popular markets in the Rio de Janeiro State, which represent valuable resources for bioprospection.

O principal objetivo desse trabalho foi estudar as plantas úteis comercializadas em feiras livres em Petrópolis e Nova Friburgo, Rio de Janeiro, Brasil. Os dados foram coletados utilizando as técnicas de observação participante, entrevistas semi-estruturadas e listagem livre com quatro comerciantes de plantas medicinais. A partir dessas entrevistas, 115 espécies (pertencentes a 49 famílias) foram relacionadas: 94 com uso medicinal, 12 com uso religioso e 9 com uso ornamental. Trinta por cento das espécies são nativas e 72 por cento possuem hábito herbáceo. As famílias mais representativas foram Asteraceae (26 espécies) e Lamiaceae (10 espécies). As espécies medicinais indicadas para o tratamento de doenças do sistema respiratório foram mais freqüentes durante o outono e inverno. A espécie denominada como Espinheira-santa (Clarisia cf. ilicifolia) obteve o valor mais alto de Importância Relativa (1,8) e a mais alta colocação em todas as estações do ano utilizando o cálculo Preference Ranking, embora seus níveis de eficiência e toxidez não tenham sido ainda estabelecidos. O estudo se mostrou relevante, pois visa reunir o conhecimento dos informantes sobre as espécies que comercializam em feiras livres e mercados populares no estado do Rio de Janeiro, que representa uma valiosa fonte para a bioprospecção.

Influence of nitrogen supply on the photoprotective response of Neoregelia cruenta under high and low light intensity.

This paper originates from a presentation at the IIIrd International Congress on Crassulacean Acid Metabolism, Cape Tribulation, Queensland, Australia, August 2001. We investigated preference for nitrogen source and the influence of ammonium nitrate on leaf pigment content, crassulacean acid metabolism (CAM) activity, and the efficiency of PSII in Neoregelia cruenta (R.Graham) L.B. Smith, a CAM bromeliad of major ecological importance to restinga (coastal sand ridge plains) environments. Plants showed a preference for ammonium over nitrate in a 24-h experiment where plants were exposed to 15NH4NO3 or NH415NO3. Mature individuals of N. cruenta were exposed to 95 and 20% full sunlight, and treated with 5 mm NH4NO3 or tap water only. After 4 months under the different treatments we found that nitrogen uptake and carotenoid content were independent of light exposure. Total chlorophyll decreased under nitrogen limitation and high light. Net titratable acid accumulation was not influenced by light or nitrogen regimes. Plants under low light showed consistently high photochemical efficiency of PSII (Fv/Fm) throughout the day. In contrast, plants under high light and nitrogen limitation showed a significant decline in Fv/Fm around midday, which recovered by the end of the light period. This decline in Fv/Fm was attributed to increased non-photochemical quenching. Our findings that plants under high light and with high nitrogen behave similarly to shade plants were unexpected. They suggest that the high light, high nitrogen leaves used a greater portion of the light absorbed in PSII antennae for photochemistry than the high light, low nitrogen plants. High nitrogen content in the leaves of N. cruenta appears to protect this CAM bromeliad against photoinhibition.

Is crassulacean acid metabolism activity in sympatric species of hemi-epiphytic stranglers such as Clusia related to carbon cycling as a photoprotective process?

A comparison of carbon isotope discrimination characteristics, crassulacean acid metabolism (CAM) activity and gas exchange together with concurrent analysis of photosystem II (PSII) chlorophyll fluorescence was conducted on leaves of sympatric species of Clusia from the restinga of Barra de Maricá, Brazil. The carbon isotope discrimination (Δ) and leaf-sap titratable acidity for leaves collected in the field indicated that the carbon metabolism of one species, C. lanceolata, was predominantly C3-like, and a second, C. fluminensis, constitutive CAM. When well-watered under glasshouse conditions C. lanceolata displayed a gas exchange pattern expected of a C3 plant, where values of instantaneous discrimination (Δ) rose from 13.5% shortly after dawn to 21.9‰ at midday, suggesting that all CO2 uptake was mediated solely by ribulose 1,5-bisphosphate carboxylase (RUBISCO). C. fluminensis showed a gas exchange pattern which clearly exhibited all four phases of CAM. Δ values during phase II ranged from -0.4‰ at dawn to 5.9‰ some 3 h later, indicating that C4 carboxylation dominated CO2 uptake during the morning with an increasing contribution by RUBISCO, suggested by the 5‰ shift in Δ at this time. The dominance of phosphoenol-pyruvate carboxylase (PEPc) activity was also found during phase IV, and extended throughout the dark period (phase I) in C. fluminensis, such that values of Δ measured were negative (-5.0 to -0.4‰). This is the first time that negative Δ values have been reported, close to those predicted theoretically for PEPc activity. The day-time uptake of CO2 mediated by PEPc could lead to futile cycling through RUBISCO. In C. fluminensis organic acids were subjected to carbon turnover between PEPc and RUBISCO during phase II of CAM, serving perhaps to dissipate ATP and reductant at a time when excess photons are absorbed. Under low levels of photosynthetically active radiation (PAR) the two species displayed similar chlorophyll fluorescence characteristics, although for the CAM C. fluminensis a lower rate of decarboxylation of acids in the afternoon was reflected in changed quenching capacity. Under high PAR both species responded directly to changes in incident radiation, reflected by decreases in photon use efficiency (ΦPSII) and the intrinsic photochemical efficiency (F V/F M), together with high and reversible quenching of excess light by the means of radiationless or thermal dissipation (q N). Both species, with such markedly different carboxylation characteristics achieve similar rates of electron transport and maintain photosynthetic integrity. Under field conditions, however the severity of a prolonged dry season caused the CAM species to become deciduous, whereas the "C3-like" species remained healthy. This suggests that the widely expected advantages of CAM do not extend to tolerance of extreme environmental conditions, in contrast to the more C3-like of these sympatric species.