Igor Florez-Sarasa

Igor Florez-Sarasa
CRAG Centre for Research in Agricultural Genomics | CRAG

PhD
Ramon y Cajal Researcher

About

56
Publications
10,226
Reads
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2,238
Citations
Citations since 2016
29 Research Items
1715 Citations
2016201720182019202020212022050100150200250300
2016201720182019202020212022050100150200250300
2016201720182019202020212022050100150200250300
2016201720182019202020212022050100150200250300
Introduction
I am a plant physiologist with experience in leading my independent research on the regulation of plant primary metabolism under different environmental stresses in several crops (tomato, grapevine, pea, soybean, cucumber, maize and tobacco) and model organisms (Arabidopsis). My major aim is to improve our understanding on the regulation of mitochondria-chloroplast metabolic interactions, which can be used to adopt new biotechnological strategies for improving crop productivity and quality in the upcoming global change scenarios.
Additional affiliations
March 2017 - present
CRAG Centre for Research in Agricultural Genomics
Position
  • PostDoc Position
January 2013 - March 2017
Max Planck Institute of Molecular Plant Physiology
Position
  • PostDoc Position
April 2011 - January 2013
University of the Balearic Islands
Position
  • PostDoc Position

Publications

Publications (56)
Article
Full-text available
In plants salt and water stress result in an induction of respiration and accumulation of stress-related metabolites (SRMs) with osmoregulation and osmoprotection functions that benefit photosynthesis. The synthesis of SRMs may depend on an active respiratory metabolism, which can be restricted under stress by the inhibition of the cytochrome oxida...
Article
Full-text available
The alternative oxidase pathway (AOP) is associated with excess energy dissipation in leaves of terrestrial plants. To address whether this association is less important in palustrine plants, we compared the role of AOP in balancing energy and carbon metabolism in palustrine and terrestrial environments by identifying metabolic relationships betwee...
Article
Full-text available
In plants, there is a complex interaction between carbon (C) and nitrogen (N) metabolism and its coordination is fundamental for plant growth and development. In the present work, the influence of thioredoxin (Trx) m on C and N partitioning was studied using tobacco plants overexpressing Trx m from the chloroplast genome. The transgenic plants show...
Article
When growing in search for light, plants can experience continuous or occasional shading by other plants. Plant proximity causes a decrease in the ratio of R to far-red light (low R:FR) due to the preferential absorbance of R light and reflection of FR light by photosynthetic tissues of neighboring plants. This signal is often perceived before actu...
Article
Full-text available
Plant respiration provides metabolic flexibility under changing environmental conditions by modulating the activity of the nonphosphorylating alternative pathways from the mitochondrial electron transport chain, which bypass the main energy-producing components of the cytochrome oxidase pathway (COP). While adjustments in leaf primary metabolism in...
Article
Geranylgeranyl diphosphate (GGPP) produced by GGPP synthase (GGPPS) serves as a precursor for many plastidial isoprenoids, including carotenoids. Phytoene synthase (PSY) converts GGPP into phytoene, the first committed intermediate of the carotenoid pathway. Here we used biochemical, molecular, and genetic tools to characterize the plastidial membe...
Article
Full-text available
Salinity has a negative impact on plant growth, with photosynthesis being downregulated partially due to osmotic effect and enhanced cellular oxidation. Redox signaling contributes to the plant response playing thioredoxins (TRXs) a central role. In this work we explore the potential contribution of Arabidopsis TRXo1 to the photosynthetic response...
Article
Aluminum (Al) is an important factor that limits plant growth under acidic soil conditions. However, several plant species developed distinct mechanisms that limit the damage caused by high Al concentrations. In highbush blueberry (Vaccinium corymbosum), the Al resistance mechanisms are not fully understood. This study was designed to evaluate the...
Article
Significance Carotenoids are natural pigments whose properties as provitamin A and health-promoting phytonutrients make them ideal targets for biofortification. Here, we show that plastids specialized in carotenoid overaccumulation named chromoplasts can be synthetically produced in plant tissues that do not naturally develop them. We further demon...
Article
Full-text available
Climate change forecasts suggest temperature increases and lower rainfall rates, both of which challenge viticulture, particularly in semi-arid areas where water availability is critical. In this scenario, the use of the genetic variability in grapevine varieties reported around the world represents an important strategy for the selection of climat...
Preprint
Full-text available
Geranylgeranyl diphosphate (GGPP) produced by GGPP synthase (GGPPS) serves as a precursor for many plastidial isoprenoids, including carotenoids. Here we show that five different GGPPS isoforms exist in tomato (Solanum lycopersicum). From these, SlGGPPS1, 2 and 3 (or SlG1-3 in short) produce GGPP in plastids and exhibit similar kinetic parameters....
Article
Full-text available
The interaction of the alternative oxidase (AOX) pathway with nutrient metabolism is important for understanding how respiration modulates ATP synthesis and carbon economy in plants under nutrient deficiency. Although AOX activity reduces the energy yield of respiration, this enzymatic activity is upregulated under stress conditions to maintain the...
Preprint
Full-text available
Plastids, the defining organelles of plant cells, undergo physiological and morphological changes to fulfill distinct biological functions. In particular, the differentiation of chloroplasts into chromoplasts results in an enhanced storage capacity for carotenoids with industrial and nutritional value such as beta-carotene (pro-vitamin A). Here, we...
Article
Full-text available
Elevated greenhouse gases (GHG) induce adverse conditions directly and indirectly causing decreases in plant productivity. To deal with climate change effects, plants have developed various mechanisms including the fine-tuning of metabolism. Plant respiratory metabolism is highly flexible due to presence of various alternative pathways. The mitocho...
Article
The alternative oxidase (AOX) constitutes a non-phosphorylating pathway of electron transport in the mitochondrial respiratory chain that provides flexibility to energy and carbon primary metabolism. Its activity is regulated in vitro by the mitochondrial thioredoxin (TRX) system which reduces conserved cysteines residues of AOX. However, in vivo e...
Article
Plant cells suffer alterations of their redox state and increase mitochondrial ROS generation during salinity. To avoid this, they activate several mitochondrial antioxidant and redox systems including the alternative oxidase (AOX), superoxide dismutase (SOD) and the ascorbate-glutathione (ASC-GSH) cycle components in a coordinated manner. The redo...
Article
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 an...
Article
In the Mediterranean region, grapevines usually deal with drought during their summer growth season. Concurrently, grapevines are hosts to a large number of viruses from which grapevine leafroll associated virus-3 is one of the most widespread and provokes considerable economic losses in many vineyards. However, information concerning grapevine met...
Article
Mitochondria are not only major sites for energy production but also participate in several alternative functions, among these generation of nitric oxide (NO), and its different impacts on this organelle, is receiving increasing attention. The inner mitochondrial membrane contains the chain of protein complexes, and electron transfer via oxidation...
Article
Full-text available
Plants exhibit respiratory bypasses (e.g., the alternative oxidase, AOX) and increase the synthesis of carboxylates in their organs (leaves and roots) in response to phosphorus (P) deficiency which increases P uptake capacity. They also show differential expression of high-affinity inorganic phosphorus (Pi) transporters, thus avoiding P toxicity at...
Article
Despite intense research on the in vitro characterization of regulatory factors modulating the alternative oxidase (AOX) pathway, the regulation of its activity in vivo is still not fully understood. Advances concerning in vivo regulation of AOX based on the oxygen-isotope fractionation technique are reviewed, and regulatory factors that merit futu...
Chapter
Plant respiration is characterized by the existence of the alternative oxidase pathway (AOP) that competes with cytochrome oxidase pathway (COP) for the electrons of the ubiquinone pool of the mitochondrial electron transport chain, thus reducing ATP synthesis. The oxygen (O2) isotope fractionation technique is the only available to determine the e...
Article
Grapevine leafroll disease is one of the most important viral diseases of grapevine (Vitis vinifera) worldwide. Grapevine leafroll-associated virus 3 (GLRaV-3) is the most predominant virus species causing this disease. Therefore, it is important to identify GLRaV-3 effects, especially in plants which do not systematically show visual symptoms. In...
Article
The effect of arbuscular mycorrhiza (AM) symbiosis on plant growth is associated with the balance between costs and benefits. A feedback regulation loop has been described in which the higher carbohydrate cost to plants for AM symbiosis is compensated by increases in their photosynthetic rates. Nevertheless, plant carbon balance depends both on pho...
Article
Full-text available
Plant mutants for genes encoding subunits of mitochondrial complex I (CI; NADH:ubiquinone oxidoreductase), the first enzyme of the respiratory chain, display various phenotypes depending on growth conditions. Here, we examined the impact of photoperiod, a major environmental factor controlling plant development, on two Arabidopsis (Arabidopsis thal...
Article
Full-text available
The cyclic electron flow around photosystem I (CEF-PSI) increases ATP/NADPH production in the chloroplast acting as an energy balance mechanism. Higher export of reducing power from the chloroplast in CEF-PSI mutants has been correlated with higher mitochondrial alternative oxidase (AOX) capacity and protein amount under high light (HL) conditions....
Article
Full-text available
Salt respiration is defined as the increase of respiration under early salt stress. However, the response of respiration varies depending on the degree of salt tolerance and salt stress. It has been hypothesized that the activity of the alternative pathway may increase preventing over-reduction of the ubiquinone pool in response to salinity, which...
Article
The mitochondrial alternative oxidase pathway (AOP) has been suggested to act as a sink for excess reducing power generated in the chloroplast under high-light (HL) stress and thus may reduce photoinhibition. The aim of this study was to compare different species to investigate the in vivo regulation and role of AOP under HL stress. The in vivo act...
Article
Plant defense mechanisms against pathogens result in differential regulation of various processes of primary and secondary metabolism. Imaging techniques, such as fluorescence imaging and thermography, are very valuable tools providing spatial and temporal information about these processes. In this study, effects of GLRaV-3 on grapevine physiology...
Article
The mitochondrial alternative oxidase (AOX) is suggested to modulate metabolic homeostasis and is activated at transcript and protein level in cadmium (Cd)-exposed Arabidopsis thaliana plants. In this study, the importance of AOX in the metabolic response to Cd stress was investigated. Primary metabolites were determined in roots and leaves of wild...
Article
Full-text available
The development of abiotic stress resistant cultivars is of premium importance for the agriculture of developing countries. Further progress in maize performance under stresses is expected by combining marker assisted breeding with metabolite markers. In order to dissect metabolic responses and to identify promising metabolite marker candidates, me...
Article
Seedling recruitment is a critical developmental stage in the regeneration of plant populations under Mediterranean conditions that strongly depends on water availability. Seed mass and relative growth rate (RGR) may affect the early establishment of seedlings through different physiological processes. Here, we examined the effects of the seed mass...
Conference Paper
Under salt stress the alternative oxidase (AOX) may prevent over-reduction of the mitochondrial ubiquinone pool, reducing the formation of reactive oxygen species (ROS). Although several studies have established a tolerance/sensitivity degree in different genotypes of Medicago truncatula in basis to the gene expressions of antioxidant enzymes (Mhad...
Article
An experiment was designed to investigate the effect of silicon supply (0 and 500μM) on Spartina densiflora plants grown at two copper (Cu) concentrations: 0 and 15mM. Growth parameters together with total concentrations of calcium, Cu, potassium, magnesium, manganese, sodium and nitrogen were determined in roots and leaves. Photosynthetic traits w...
Article
The plant respiratory chain contains several pathways which bypass the energy-conserving electron transport complexes I, III, and IV. These energy-bypasses, including type II NAD(P)H dehydrogenases and the alternative oxidase (AOX), may have a role in redox-stabilisation and regulation, but current evidence is inconclusive. Using RNA interference,...
Article
Plant adaptations associated with a high efficiency of phosphorus (P) acquisition can be used to increase productivity and sustainability in a world with a growing population and decreasing rock phosphate reserves. White lupin (Lupinus albus) produces cluster roots that release carboxylates to efficiently mobilize P from P-sorbing soils. It has bee...
Article
Ca(2+)-dependent oxidation of cytosolic NADPH is mediated by NDB1, which is an external type II NADPH dehydrogenase in the plant mitochondrial electron transport chain. Using RNA interference, the NDB1 transcript was suppressed by 80% in Arabidopsis thaliana plants, and external Ca(2+)-dependent NADPH dehydrogenase activity became undetectable in i...
Article
Nitric oxide (NO) has emerged as an important signaling molecule in plants, but little is known about the effects of reactive nitrogen species in plant mitochondria. In this study, the effects of DETA-NONOate, a pure NO slow generator, and of SIN-1 (3-morpholinosydnonimine), a peroxynitrite producer, on the activities of respiratory pathways, enzym...
Article
• The effect of previous light conditions on metabolite and transcript levels was investigated in leaves of Arabidopsis thaliana during illumination and after light-enhanced dark respiration (LEDR), when dark respiration was measured. • Primary carbon metabolites and the expression of light-responsive respiratory genes were determined in A. thalian...
Article
Full-text available
Leaf water gets isotopically enriched through transpiration, and diffusion of enriched water through the leaf depends on transpiration flow and the effective path length (L). The aim of this work was to relate L with physiological variables likely to respond to similar processes. We studied the response to drought and vein severing of leaf lamina h...
Article
Full-text available
To investigate the role of plant mitochondria in drought tolerance, the response to water deprivation was compared between Nicotiana sylvestris wild type (WT) plants and the CMSII respiratory complex I mutant, which has low-efficient respiration and photosynthesis, high levels of amino acids and pyridine nucleotides, and increased antioxidant capac...
Article
Full-text available
Plants may exhibit some degree of acclimation after experiencing drought, but physiological adjustments to consecutive cycles of drought and re-watering (recovery) have scarcely been studied. The Mediterranean evergreen holm oak (Q. ilex) and the semi-deciduous rockrose (C. albidus) showed some degree of acclimation after the first of three drought...
Article
Full-text available
The in vivo activity of the alternative pathway (ν(alt)) has been studied using the oxygen isotope fractionation method in leaves of Arabidopsis thaliana modified for the expression of the AtAOX1a gene by anti-sense (AS-12) or overexpression (XX-2). Under non-stressful conditions, ν(alt) was similar in all plant lines regardless of its different al...
Article
Full-text available
Mitochondria play an essential role in reactive oxygen species (ROS) signal transduction in plants. Redox regulation is an essential feature of mitochondrial function, with thioredoxin (Trx), involved in disulphide/dithiol interchange, playing a prominent role. To explore the participation of mitochondrial PsTrxo1, Mn-superoxide dismutase (Mn-SOD),...
Article
*The effects of zinc (Zn) toxicity on photosynthesis and respiration were investigated in sugar beet (Beta vulgaris) plants grown hydroponically with 1.2, 100 and 300 microM Zn. *A photosynthesis limitation analysis was used to assess the stomatal, mesophyll, photochemical and biochemical contributions to the reduced photosynthesis observed under Z...
Article
Full-text available
The interaction of photosynthesis and respiration has been studied in vivo under conditions of limited water supply and after consecutive rewatering. The role of the alternative (valt) and cytochrome (vcyt) pathways on drought stress-induced suppression of photosynthesis and during photosynthetic recovery was examined in the Nicotiana sylvestris wi...
Article
In vitro studies demonstrated that alternative oxidase (AOX) is biochemically regulated by a sulfhydryl-disulfide system, interaction with alpha-ketoacids, ubiquinone pool redox state and protein content among others. However, there is still scarce information about the in vivo regulation of the AOX. Cucumis sativus wild-type (WT) and MSC16 mutant...
Article
Full-text available
While the responses of photosynthesis to water stress have been widely studied, acclimation to sustained water stress and recovery after re-watering is poorly understood. In particular, the factors limiting photosynthesis under these conditions, and their possible interactions with other environmental conditions, are unknown. To assess these issues...
Article
We tested the hypotheses that relative activity of the less efficient alternative oxidase (AOX) path changes with diurnal temperature changes, and thus changes carbon use efficiency with temperature. The activities of the alternative and cytochrome oxidase (COX) paths in plant tissues of three species were determined by measuring 18O/16O discrimina...
Article
The close rosette growth form, short petioles and small leaves of Arabidopsis thaliana make measurements with commercial gas exchange cuvettes difficult. This difficulty can be overcome by growing A. thaliana plants in 'ice-cream cone-like' soil pots. This design permitted simultaneous gas exchange and chlorophyll fluorescence measurements from whi...
Article
The activities of the cytochrome and alternative respiratory pathways were measured during the growth cycle in Arabidopsis thaliana using a newly developed Isotope Ratio Mass Spectrometer (IRMS) dual-inlet system that allows very precise measurements of oxygen-isotope fractionation under low oxygen consumption rates. Under optimum growth conditions...

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Project
I have manipulated endogenous Arabidopsis QPT (quinolinate phosphoribosyltransferase) levels to deregulate NAD production. Knock-down mutants for the single qpt gene in Arabidopsis exhibited a severe reduced growth due to diminished pools of NAD, an increased NAD/NADH ratio and drastic perturbations of C and N metabolism. I next used a respiratory complex I mutant of Arabidopsis to link the increase of NAD biosynthesis and contents to an impaired photoperiodic response, correlated with significant reconfiguration of C and N metabolism, and redox perturbations. These experiments highlight a critical role of NAD in C/N interactions by altering nitrogen assimilation and carbon primary metabolism upon photorespiratory conditions. These results provide the foundations for probing the role of NAD in signalling mechanisms modulating major metabolic functions. The study of qpt mutant requires some additional experiments prior to being communicated to the scientific community. An additional paper describing a mitochondrial mutant is under revision in Plant Physiology journal (Pétriacq et al. PP2016-00131).