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URI permanente para esta coleçãohttps://locus.ufv.br/handle/123456789/11846
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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 Metabolic control and regulation of the tricarboxylic acid cycle in photosynthetic and heterotrophic plant tissues(Plant, Cell and Environment, 2011-04-08) Nunes-Nesi, Adriano; Araújo, Wagner L.; Nikoloski, Zoran; Sweetlove, Lee J.; Fernie, Alisdair R.The tricarboxylic acid (TCA) cycle is a crucial component of respiratory metabolism in both photosynthetic and heterotrophic plant organs. All of the major genes of the tomato TCA cycle have been cloned recently, allowing the generation of a suite of transgenic plants in which the majority of the enzymes in the pathway are progres- sively decreased. Investigations of these plants have provided an almost complete view of the distribution of control in this important pathway. Our studies suggest that citrate synthase, aconitase, isocitrate dehydrogenase, succi- nyl CoA ligase, succinate dehydrogenase, fumarase and malate dehydrogenase have control coefficients flux for res- piration of -0.4, 0.964, -0.123, 0.0008, 0.289, 0.601 and 1.76, respectively; while 2-oxoglutarate dehydrogenase is esti- mated to have a control coefficient of 0.786 in potato tubers. These results thus indicate that the control of this pathway is distributed among malate dehydrogenase, aconitase, fumarase, succinate dehydrogenase and 2-oxoglutarate dehydrogenase. The unusual distribution of control esti- mated here is consistent with specific non-cyclic flux mode and cytosolic bypasses that operate in illuminated leaves. These observations are discussed in the context of known regulatory properties of the enzymes and some illustrative examples of how the pathway responds to environmental change are given.Item Exploring natural variation of photosynthetic, primary metabolism and growth parameters in a large panel of Capsicum chinense accessions(Planta, 2015-05-26) Rosado-Souza, Laise; Scossa, Federico; Chaves, Izabel S.; Kleessen, Sabrina; Salvador, Luiz F. D.; Milagre, Jocimar C.; Finger, Fernando; Bhering, Leonardo L.; Sulpice, Ronan; Araújo, Wagner L.; Nikoloski, Zoran; Fernie, Alisdair R.; Nunes-Nesi, AdrianoDiversity of accessions within the same species provides an alternative method to identify physiological and metabolic traits that have large effects on growth regulation, biomass and fruit production. Here, we investigated physiological and metabolic traits as well as parameters related to plant growth and fruit production of 49 phenotypically diverse pepper accessions of Capsicum chinense grown ex situ under controlled conditions. Although single-trait analysis identified up to seven distinct groups of accessions, working with the whole data set by multivariate analyses allowed the separation of the 49 accessions in three clusters. Using all 23 measured parameters and data from the geographic origin for these accessions, positive correlations between the combined phenotypes and geographic origin were observed, supporting a robust pattern of isolation-by-distance. In addition, we found that fruit set was positively correlated with photosynthesis-related parameters, which, however, do not explain alone the differences in accession susceptibility to fruit abortion. Our results demonstrated that, although the accessions belong to the same species, they exhibit considerable natural intraspecific variation with respect to physiological and metabolic parameters, presenting diverse adaptation mechanisms and being a highly interesting source of information for plant breeders. This study also represents the first study combining photosynthetic, primary metabolism and growth parameters for Capsicum to date.Item Impaired malate and fumarate accumulation due the mutation of tonoplast dicarboxylate transporter(Plant Physiology, 2017-09-20) Medeiros, David B.; Barros, Kallyne; Barros, Jessica AS; Omena-Garcia, Rebeca P; Detmann, Kelly C; Silva, Willian Batista; DaMatta, Fabio; Nunes-Nesi, Adriano; Araújo, Wagner L.; Arrivault, Stéphanie; Sanglard, Lilian Vincis Pereira; Daloso, Danilo M.; Fernie, Alisdair R.Malate is a central metabolite involved in a multiplicity of plant metabolic pathways, being associated with mitochondrial metabolism and playing significant roles n stomatal movements. Vacuolar malate transport has been characterized at the molecular level and is performed by at least one carrier protein and two channels in Arabidopsis vacuoles. The absence of the Arabidopsis thaliana tonoplast Dicarboxylate Transporter (tDT) in tdt knockout mutant was previously associated with an impaired accumulation of malate and fumarate in leaves. Here, we investigated the consequences of this lower accumulation on stomatal behaviour and photosynthetic capacity as well as ts putative metabolic impacts. Neither the stomatal conductance (g s ) nor the kinetic responses to dark, light or high CO 2 were highly affected in tdt plants. In addition, we did not observe any impact on stomatal aperture following incubation with either bscisic acid (ABA), malate or citrate. Further, an effect on photosynthetic capacity was not observed in the mutant lines. However, leaf mitochondrial metabolism was affected in the tdt plants. Levels of the intermediates of the tricarboxylic acid cycle were altered and increases in both light and dark respiration were observed. We conclude that manipulation of the tonoplastic organic acid transporter impacted mitochondrial metabolism, while the overall stomatal and photosynthetic capacity were unaffected.