Artigos
URI permanente para esta coleçãohttps://locus.ufv.br/handle/123456789/11846
Navegar
5 resultados
Resultados da Pesquisa
Item Modulation of auxin signalling through DIAGETROPICA and ENTIRE differentially affects tomato plant growth via changes in photosynthetic and mitochondrial metabolism(Plant, Cell & Environment, 2019-02) Batista‐ Silva, Willian; Medeiros, David B.; Rodrigues‐ Salvador, Acácio; Daloso, Danilo M.; Omena‐ Garcia, Rebeca P.; Oliveira, Franciele Santos; Pino, Lilian Ellen; Peres, Lázaro Eustáquio Pereira; Nunes‐ Nesi, Adriano; Fernie, Alisdair R.; Zsögön, Agustín; Araújo, Wagner L.Auxin modulates a range of plant developmental processes including embryogenesis, organogenesis, and shoot and root development. Recent studies have shown that plant hormones also strongly influence metabolic networks, which results in altered growth phenotypes. Modulating auxin signalling pathways may therefore provide an opportunity to alter crop performance. Here, we performed a detailed physiological and metabolic characterization of tomato (Solanum lycopersicum) mutants with either increased (entire) or reduced (diageotropica—dgt) auxin signalling to investigate the consequences of altered auxin signalling on photosynthesis, water use, and primary metabolism. We show that reduced auxin sensitivity in dgt led to anatomical and physiological modifications, including altered stomatal distribution along the leaf blade and reduced stomatal conductance, resulting in clear reductions in both photosynthesis and water loss in detached leaves. By contrast, plants with higher auxin sensitivity (entire) increased the photosynthetic capacity, as deduced by higher Vcmax and Jmax coupled with reduced stomatal limitation. Remarkably, our results demonstrate that auxin‐sensitive mutants (dgt) are characterized by impairments in the usage of starch that led to lower growth, most likely associated with decreased respiration. Collectively, our findings suggest that mutations in different components of the auxin signalling pathway specifically modulate photosynthetic and respiratory processes.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 The influence of alternative pathways of respiration that utilize branched‐chain amino acids following water shortage in Arabidopsis(Plant, Cell and Environment, 2015-11-30) Pires, Marcel V.; Pereira Júnior, Adilson A.; Medeiros, David B.; Daloso, Danilo M.; Pham, Phuong Anh; Barros, Kallyne A.; Engqvist, Martin K. M.; Florian, Alexandra; Krahnert, Ina; Maurino, Veronica G.; Araújo, Wagner L.; Fernie, Alisdair R.During dark‐induced senescence isovaleryl‐CoA dehydrogenase (IVDH) and D‐2‐hydroxyglutarate dehydrogenase (D‐2HGDH) act as alternate electron donors to the ubiquinol pool via the electron‐transfer flavoprotein/electron‐transfer flavoprotein:ubiquinone oxidoreductase (ETF/ETFQO) pathway. However, the role of this pathway in response to other stresses still remains unclear. Here, we demonstrated that this alternative pathway is associated with tolerance to drought in Arabidopsis. In comparison with wild type (WT) and lines overexpressing D‐2GHDH, loss‐of‐function etfqo‐1, d2hgdh‐2 and ivdh‐1 mutants displayed compromised respiration rates and were more sensitive to drought. Our results demonstrated that an operational ETF/ETFQO pathway is associated with plants' ability to withstand drought and to recover growth once water becomes replete. Drought‐induced metabolic reprogramming resulted in an increase in tricarboxylic acid (TCA) cycle intermediates and total amino acid levels, as well as decreases in protein, starch and nitrate contents. The enhanced levels of the branched‐chain amino acids in loss‐of‐function mutants appear to be related to their increased utilization as substrates for the TCA cycle under water stress. Our results thus show that mitochondrial metabolism is highly active during drought stress responses and provide support for a role of alternative respiratory pathways within this response.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.