Biologia Vegetal
URI permanente desta comunidadehttps://locus.ufv.br/handle/123456789/11836
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43 resultados
Resultados da Pesquisa
Item The mitochondrial thioredoxin system contributes to the metabolic responses under drought episodes in Arabidopsis(Plant and Cell Physiology, 2019-01) Fonseca-Pereira, Paula da; Daloso, Danilo M.; Gago, Jorge; Silva, Franklin Magnum de Oliveira; Condori-Apfata, Jorge A.; Florez-Sarasa, Igor; Tohge, Takayuki; Reichheld, Jean-Philippe; Nunes-Nesi, Adriano; Fernie, Alisdair R.; Araujo, Wagner L.Thioredoxins (Trxs) modulate metabolic responses during stress conditions; however, the mechanisms governing the responses of plants subjected to multiple drought events and the role of Trxs under these conditions are not well understood. Here we explored the significance of the mitochondrial Trx system in Arabidopsis following exposure to single and repeated drought events. We analyzed the previously characterized NADPH-dependent Trx reductase A and B double mutant (ntra ntrb) and two independent mitochondrial thioredoxin o1 (trxo1) mutant lines. Following similar reductions in relative water content (∼50%), Trx mutants subjected to two drought cycles displayed a significantly higher maximum quantum efficiency (Fv/Fm) and were less sensitive to drought than their wild-type counterparts and than all genotypes subjected to a single drought event. Trx mutant plants displayed a faster recovery after two cycles of drought, as observed by the higher accumulation of secondary metabolites and higher stomatal conductance. Our results indicate that plants exposed to multiple drought cycles are able to modulate their subsequent metabolic and physiological response, suggesting the occurrence of an exquisite acclimation in stressed Arabidopsis plants. Moreover, this differential acclimation involves the participation of a set of metabolic changes as well as redox poise alteration following stress recovery.Item Unraveling interfaces between energy metabolism and cell cycle in plants(Trends in Plant Science, 2018-08) Nunes-Nesi, Adriano; Siqueira, João Antonio; Hardoim, Pablo; Ferreira, Paulo C. G.; Hemerly, Adriana S.Oscillation in energy levels is widely variable in dividing and differentiated cells. To synchronize cell proliferation and energy fluctuations, cell cycle-related proteins have been implicated in the regulation of mitochondrial energy-generating pathways in yeasts and animals. Plants have chloroplasts and mitochondria, coordinating the cell energy flow. Recent findings suggest an integrated regulation of these organelles and the nuclear cell cycle. Furthermore, reports indicate a set of interactions between the cell cycle and energy metabolism, coordinating the turnover of proteins in plants. Here, we discuss how cell cycle-related proteins directly interact with energy metabolism-related proteins to modulate energy homeostasis and cell cycle progression. We provide interfaces between cell cycle and energy metabolism-related proteins that could be explored to maximize plant yield.Item Metallic nanoparticles influence the structure and function of the photosynthetic apparatus in plants(Plant Physiology and Biochemistry, 2018-09) Nunes-Nesi, Adriano; Tighe-Neira, Ricardo; Carmora, Erico; Recio, Gonzalo; Reyes-Diaz, Marjorie; Alberdi, Miren; Rengel, Zed; Inostroza-Blancheteau, ClaudioThe applications of nanoparticles continue to expand into areas as diverse as medicine, bioremediation, cosmetics, pharmacology and various industries, including agri-food production. The widespread use of nanoparticles has generated concerns given the impact these nanoparticles – mostly metal-based such as CuO, Ag, Au, CeO2, TiO2, ZnO, Co, and Pt - could be having on plants. Some of the most studied variables are plant growth, development, production of biomass, and ultimately oxidative stress and photosynthesis. A systematic appraisal of information about the impact of nanoparticles on these processes is needed to enhance our understanding of the effects of metallic nanoparticles and oxides on the structure and function on the plant photosynthetic apparatus. Most nanoparticles studied, especially CuO and Ag, had a detrimental impact on the structure and function of the photosynthetic apparatus. Nanoparticles led to a decrease in concentration of photosynthetic pigments, especially chlorophyll, and disruption of grana and other malformations in chloroplasts. Regarding the functions of the photosynthetic apparatus, nanoparticles were associated with a decrease in the photosynthetic efficiency of photosystem II and decreased net photosynthesis. However, CeO2 and TiO2 nanoparticles may have a positive effect on photosynthetic efficiency, mainly due to an increase in electron flow between the photosystems II and I in the Hill reaction, as well as an increase in Rubisco activity in the Calvin and Benson cycle. Nevertheless, the underlying mechanisms are poorly understood. The future mechanistic work needs to be aimed at characterizing the enhancing effect of nanoparticles on the active generation of ATP and NADPH, carbon fixation and its incorporation into primary molecules such as photo-assimilates.Item Downregulation of the δ-subunit reduces mitochondrial ATP synthase levels, alters respiration, and restricts growth and gametophyte development in Arabidopsis(The Plant Cell, 2012-07) Nunes-Nesi, Adriano; Geisler, Daniela A.; Päpke, Carola; Obata, Toshihiro; Matthes, Annemarie; Schneitz, Kay; Maximova, Eugenia; Araújo, Wagner L.; Fernie, Alisdair R.; Persson, StaffanThe mitochondrial ATP synthase (F1Fo complex) is an evolutionary conserved multimeric protein complex that synthesizes the main bulk of cytosolic ATP, but the regulatory mechanisms of the subunits are only poorly understood in plants. In yeast, the δ-subunit links the membrane-embedded Fo part to the matrix-facing central stalk of F1. We used genetic interference and an inhibitor to investigate the molecular function and physiological impact of the δ-subunit in Arabidopsis thaliana. Delta mutants displayed both male and female gametophyte defects. RNA interference of delta resulted in growth retardation, reduced ATP synthase amounts, and increased alternative oxidase capacity and led to specific long-term increases in Ala and Gly levels. By contrast, inhibition of the complex using oligomycin triggered broad metabolic changes, affecting glycolysis and the tricarboxylic acid cycle, and led to a successive induction of transcripts for alternative respiratory pathways and for redox and biotic stress-related transcription factors. We conclude that (1) the δ-subunit is essential for male gametophyte development in Arabidopsis, (2) a disturbance of the ATP synthase appears to lead to an early transition phase and a long-term metabolic steady state, and (3) the observed long-term adjustments in mitochondrial metabolism are linked to reduced growth and deficiencies in gametophyte development.Item Data-mining bioinformatics: connecting adenylate transport and metabolic responses to stress(Trends in Plant Science, 2018-11) Fonseca-Pereira, Paula da; Neri-Silva, Roberto; Cavalcanti, João Henrique F.; Brito, Danielle S.; Weber, Andreas P. M.; Araújo, Wagner L.; Nunes-Nesi, AdrianoAdenine nucleotides are essential in countless processes within the cellular metabolism. In plants, ATP is mainly produced in chloroplasts and mitochondria through photophosphorylation and oxidative phosphorylation, respectively. Thus, efficient adenylate transport systems are required for intracellular energy partitioning between the cell organelles. Adenylate carriers present in different subcellular compartments have been previously identified and biochemically characterized in plants. Here, by using data-mining bioinformatics tools, we propose how, and to what extent, these carriers integrate energy metabolism within a plant cell under different environmental conditions. We demonstrate that the expression pattern of the corresponding genes is variable under different environmental conditions, suggesting that specific adenylate carriers have distinct and nonredundant functions in plants.Item Differential root and shoot responses in the metabolism of tomato plants exhibiting reduced levels of gibberellin(Environmental and Experimental Botany, 2019-01) Martins, Auxiliadora O.; Omena-Garcia, Rebeca P.; Oliveira, Franciele S.; Silva, Welder A.; Hajirezaei, Mohammad-Reza; Vallarino, José G.; Ribeiro, Dimas Mendes; Fernie, Alisdair R.; Nunes-Nesi, Adriano; Araújo, Wagner L.The ability to adapt to the environment is crucial for plant survival and thus a refined communication system capable of integrating endogenous and exogenous signals and further relaying this information to different parts of the plant is a key component of such adaptability. Given that they grow in highly distinct environments it is arguably unsurprising that roots and shoots display different responses to a given environmental condition. Accordingly, a higher sensitivity of roots to gibberellins (GAs) allows rapid adjustments in growth and development possibly triggering (a) stress tolerance mechanism(s). Here we investigated the differential metabolic responses between root and shoot following reductions of the endogenous GA content using tomato (Solanum lycopersicum L.) plants deficient in GA biosynthesis (gib3, moderately deficient, gib2, intermediate deficiency and gib1, extremely deficient in GAs). GA depletion impedes shoot growth to a greater extent than root growth in all mutants. Moreover, the greater the reduction in GA content the greater the extent of a disturbance at the metabolic level. Low leaf carbohydrate contents were observed in plants displaying higher root growth, suggesting an enhanced flow of photoassimilate to support root growth. Large increases in amino acids contents of either roots or shoot were observed. The increased amino acid content was coupled to reduced levels of TCA cycle intermediates suggesting that these changes are directly linked to early reactions of nitrogen assimilation. The combined data are discussed in terms of our current understanding of the interaction between GA and primary metabolism and their crosstalk in environmental responses.Item Increased urea availability promotes adjustments in C/N metabolism and lipid content without impacting growth in Chlamydomonas reinhardtii(Metabolomics, 2019-03) Batista, Aline D.; Rosa, Rinamara M.; Machado, Mariana; Magalhães, Alan S.; Shalaguti, Bárbara A.; Gomes, Priscilla F.; Covell, Lidiane; Vaz, Marcelo G. M. V.; Araújo, Wagner L.; Nunes-Nesi, AdrianoThe use of urea as a nitrogen (N) source by Chlorophytes usually enhances biomass and lipid production when compared to ammonium (NH4+). However, the metabolic shifts displayed byChlamydomonas reinhardtii growing with this organic N source are not known. This study aimed: (i) to characterize the metabolism of C. reinhardtii cultivated in media containing only urea as N source as well as combined with different NH4+ ratios; (ii) to understand how metabolism respond to urea availability. Specific quantification of metabolites using 96-well microplates, and high-performance liquid chromatography combined with non-targeted metabolite profiling by gas chromatography (GC)–time-of-flight (TOF)-mass spectrometry (MS) were used in this study. In addition, GC analysis was used to determine fatty acid profiling. The use of urea did not alter the growth rate in comparison with NH4+. Interestingly, the cell number decreased and the cell size increased proportionally with urea availability. Furthermore, chlorophyll, protein and lipid contents increased with the amount of urea. Regarding the fatty acid profile, oleic acid (C18:1 w8) decreased with amount of urea, while linoleic acid (C18:2 w6) doubled in urea-containing medium. These results indicate that urea promotes remarkable adjustments in metabolism, without drastic changes in biomass, promoting changes in carbohydrate and amino acid metabolism, as well as in lipids production and fatty acid profile.Item Metabolic diversity in tuber tissues of native Chiloé potatoes and commercial cultivars of Solanum tuberosum ssp. tuberosum L.(Metabolomics, 2018-10) Silva, Franklin Magnum de Oliveira; Machado, Mariana; Nunes-Nesi, Adriano; Inostroza-Blancheteau, Claudio; Durán, Fabiola; Solano, Jaime; Obata, Toshihiro; Fernie, Alisdair R.; Reyes-Díaz, MarjorieThe native potatoes (Solanum tuberosum ssp. tuberosum L.) cultivated on Chiloé Island in southern Chile have great variability in terms of tuber shape, size, color and flavor. These traits have been preserved throughout generations due to the geographical position of Chiloé, as well as the different uses given by local farmers. The present study aimed to investigate the diversity of metabolites in skin and pulp tissues of eleven native accessions of potatoes from Chile, and evaluate the metabolite associations between tuber tissues. For a deeper characterization of these accessions, we performed a comprehensive metabolic study in skin and pulp tissues of tubers, 3 months after harvesting. Specific targeted quantification of metabolites using 96 well microplates, and high-performance liquid chromatography combined with non-targeted metabolite profiling by gas chromatography time-of-flight mass spectrometry were used in this study. We observed differential levels of antioxidant activity and phenolic compounds between skin and pulp compared to a common commercial cultivar (Desireé). In addition, we uncovered considerable metabolite variability between different tuber tissues and between native potatoes. Network correlation analysis revealed different metabolite associations among tuber tissues that indicate distinct associations between primary metabolite and anthocyanin levels, and antioxidant activity in skin and pulp tissues. Moreover, multivariate analysis lead to the grouping of native and commercial cultivars based on metabolites from both skin and pulp tissues. As well as providing important information to potato producers and breeding programs on the levels of health relevant phytochemicals and other abundant metabolites such as starch, proteins and amino acids, this study highlights the associations of different metabolites in tuber skins and pulp, indicating the need for distinct strategies for metabolic engineering in these tissues. Furthermore, this study shows that native Chilean potato accessions have great potential as a natural source of phytochemicals.Item On the role of plant mitochondrial metabolism and its impact on photosynthesis in both optimal and sub-optimal growth conditions(Photosynthesis Research, 2014-02) Araújo, Wagner L.; Nunes-Nesi, Adriano; Fernie, Alisdair R.Given that the pathways of photosynthesis and respiration catalyze partially opposing processes, it follows that their relative activities must be carefully regulated within plant cells. Recent evidence has shown that the components of the mitochondrial electron transport chain are essential for the proper maintenance of intracellular redox gradients, to allow considerable rates of photorespiration and in turn efficient photosynthesis. Thus considerable advances have been made in understanding the interaction between respiration and photosynthesis during the last decades and the potential mechanisms linking mitochondrial function and photosynthetic efficiency will be reviewed. Despite the fact that manipulation of various steps of mitochondrial metabolism has been demonstrated to alter photosynthesis under optimal growth conditions, it is likely that these changes will, by and large, not be maintained under sub-optimal situations. Therefore producing plants to meet this aim remains a critical challenge. It is clear, however, that although there have been a range of studies analysing changes in respiratory and photosynthetic rates in response to light, temperature and CO2, our knowledge of the environmental impact on these processes and its linkage still remains fragmented. We will also discuss the metabolic changes associated to plant respiration and photosynthesis as important components of the survival strategy as they considerably extend the period that a plant can withstand to a stress situation.Item Antisense inhibition of the 2-oxoglutarate dehydrogenase complex in tomato demonstrates its importance for plant respiration and during leaf senescence and fruit maturation(The Plant Cell, 2012-06) Araújo, Wagner L.; Nunes-Nesi, Adriano; Tohge, Takayuki; Osorio, Sonia; Lohse, Marc; Balbo, Ilse; Krahnert, Ina; Sienkiewicz-Porzucek, Agata; Usadel, Björn; Fernie, Alisdair R.Transgenic tomato (Solanum lycopersicum) plants expressing a fragment of the gene encoding the E1 subunit of the 2-oxoglutarate dehydrogenase complex in the antisense orientation and exhibiting substantial reductions in the activity of this enzyme exhibit a considerably reduced rate of respiration. They were, however, characterized by largely unaltered photosynthetic rates and fruit yields but restricted leaf, stem, and root growth. These lines displayed markedly altered metabolic profiles, including changes in tricarboxylic acid cycle intermediates and in the majority of the amino acids but unaltered pyridine nucleotide content both in leaves and during the progression of fruit ripening. Moreover, they displayed a generally accelerated development exhibiting early flowering, accelerated fruit ripening, and a markedly earlier onset of leaf senescence. In addition, transcript and selective hormone profiling of gibberellins and abscisic acid revealed changes only in the former coupled to changes in transcripts encoding enzymes of gibberellin biosynthesis. The data obtained are discussed in the context of the importance of this enzyme in both photosynthetic and respiratory metabolism as well as in programs of plant development connected to carbon–nitrogen interactions.