Separación mediante electrofóresis en 2-D de membranas tilacoidales

4 Pags.- 2 Figs.La deficiencia en hierro disminuye marcadamente la tasa de fotosíntesis. Las hojas deficientes en hierro reducen el número membranas tilacoidales por cloroplasto (Spiller y Terry 1980) y los componentes de las membranas: transportadores electrónicos de la cadena fotosintética (Spiller y Terry 1980), clorofilas y carotenoides (Abadía y Abadía 1993, Morales et al., 1990). Una de las principales características de las hojas deficientes en hierro es la clorosis debida a la baja concentración de clorofilas y carotenoides por área (Morales et al. 1990, 1994; Abadía y Abadía 1993). No todos los pigmentos disminuyen en igual cantidad, ya que existe una pérdida preferente de Chl b y por lo tanto de antena extrínseca LHC. Además Riethman y Sherman 1988 y Burnap et al 1993 publicaron la existencia de un nuevo pigmento-proteína inducido por la deficiencia de hierro en cianobacteria. Todo parece indicar que el patrón polipeptídico de las membranas de hojas deficientes en hierro podría ser distinto al de las membranas de las hojas control. Aunque en nuestro grupo de investigación ya se habían efectuado trabajos sobre electroforesis en 2 D (González-Vallejo, 1999), se han aprovechado los nuevos avances de la proteómica para llevar a cabo esta nueva aproximación.Financiado por los proyectos del Plan Nacional de Investigación AGL2000-1721 a AA, y PB97-1176 y BOS2001-2343 a JA.Peer reviewe

Image techniques: New approaches in metal homeostasis

1 .pdf copia del original presentado por los autores al Meeting.Plant physiological processes take place in a complex cellular environment. Organs are complex structures made up of different tissues with distinct cell types. Traditional biochemistry involves the analysis of bulk samples containing am ixture of heterogeneous tissues, leading to a non correct interpretation of the results. This averaging effect can only be overcome by increasing the spatial resolution of analysis to a tissue-or even cell- specific level, in other words, by using image techniques.This study was supported by MICINN projects AGL2006-1416 and AGL2007-61948,co-financed with FEDER, the European Commission (EU 6th Framework Integrated Project ISAFRUIT, Contract no.FP6-FOOD-CT-2006-016279), and the Aragón Government(groupA03).Peer reviewe

Cambios producidos por el tratamiento de Fe sobre las concentraciones de ácidos orgánicos en xilema de melocotoneros afectados por clorosis férrica

4 Pags.- 3 Figs.La deficiencia de hierro se considera uno de los mayores estreses abióticos que afectan a los frutales cultivados en suelos calcáreos del área mediterránea. Se conoce desde hace décadas que las concentraciones de ácidos orgánicos aumentan en todas las partes de la planta con la clorosis férrica (ver revisión de Abadía et al., 2001). Este aspecto ha sido muy poco estudiado en árboles frutales, en especial por lo que se refiere a la savia de xilema y apoplasto. Chatti (1997) indicó que la concentración de ácidos orgánicos de la savia de melocotonero cambia ligeramente con el grado de clorosis. López-Millán et al., (2001) indicaron que la concentración total de ácidos orgánicos en apoplasto de peral aumenta con el grado de clorosis. También se encontró un aumento de la concentración de ácidos orgánicos en hojas de manzano y peral cloróticos (Sun et al., 1987; López-Millán et al., 2001). Entre los métodos empleados para remediar la clorosis figuran las inyecciones de implantes de Fe en el tronco de los árboles. Se ha descrito que este método es efectivo para aliviar la clorosis, con un efecto duradero por lo menos durante dos o tres años (Hurley et al. 1986). El principal objetivo de este trabajo es investigar los cambios producidos por las inyecciones de implantes de Fe sobre la composición en ácidos orgánicos en xilema de árboles cloróticos.Financiado por los proyectos del Plan Nacional de Investigación AGL2000-1721 a AA, y PB97-1176 y BOS2001-2343 a JA.Peer reviewe

Metal species involved in long distance metal transport in plants

20 Pags.- 2 Tabls.- 1 Fig. © 2014 Álvarez-Fernández, Díaz-Benito, Abadía, López-Millán and Abadía. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.The mechanisms plants use to transport metals from roots to shoots are not completely understood. It has long been proposed that organic molecules participate in metal translocation within the plant. However, until recently the identity of the complexes involved in the long-distance transport of metals could only be inferred by using indirect methods, such as analyzing separately the concentrations of metals and putative ligands and then using in silico chemical speciation software to predict metal species. Molecular biology approaches also have provided a breadth of information about putative metal ligands and metal complexes occurring in plant fluids. The new advances in analytical techniques based on mass spectrometry and the increased use of synchrotron X-ray spectroscopy have allowed for the identification of some metal-ligand species in plant fluids such as the xylem and phloem saps. Also, some proteins present in plant fluids can bind metals and a few studies have explored this possibility. This study reviews the analytical challenges researchers have to face to understand long-distance metal transport in plants as well as the recent advances in the identification of the ligand and metal-ligand complexes in plant fluids.This study was supported by the Spanish Ministry of Economy and Competitiveness (projects AGL2010-16515 and AGL2012-31988), and the Aragón Government (group A03). Pablo Díaz-Benito was supported by a MINECO-FPI grant.Peer reviewe

Metabolite Profile Changes in Xylem Sap and Leaf Extracts of Strategy I Plants in Response to Iron Deficiency and Resupply

The metabolite profile changes induced by Fe deficiency in leaves and xylem sap of several Strategy I plant species have been characterized. We have confirmed that Fe deficiency causes consistent changes both in the xylem sap and leaf metabolite profiles. The main changes in the xylem sap metabolite profile in response to Fe deficiency include consistent decreases in amino acids, N-related metabolites and carbohydrates, and increases in TCA cycle metabolites. In tomato, Fe resupply causes a transitory flush of xylem sap carboxylates, but within 1 day the metabolite profile of the xylem sap from Fe-deficient plants becomes similar to that of Fe-sufficient controls. The main changes in the metabolite profile of leaf extracts in response to Fe deficiency include consistent increases in amino acids and N-related metabolites, carbohydrates and TCA cycle metabolites. In leaves, selected pairs of amino acids and TCA cycle metabolites show high correlations, with the sign depending of the Fe status. These data suggest that in low photosynthesis, C-starved Fe-deficient plants anaplerotic reactions involving amino acids can be crucial for short-term survival

Leaf structural changes associated with iron deficiency chlorosis in field-grown pear and peach: physiological implications

The final version is available at: http://www.springerlink.com/content/y62g0r6712184032/fulltext.pdfPlants grown in calcareous, high pH soils develop Fe deficiency chlorosis. While the physiological parameters of Fe-deficient leaves have been often investigated, there is a lack of information regarding structural leaf changes associated with such abiotic stress. Iron-sufficient and Fe-deficient pear and peach leaves have been studied, and differences concerning leaf epidermal and internal structure were found. Iron deficiency caused differences in the aspect of the leaf surface, which appeared less smooth in Fe-deficient than in Fe-sufficient leaves. Iron deficiency reduced the amount of soluble cuticular lipids in peach leaves, whereas it reduced the weight of the abaxial cuticle in pear leaves. In both plant species, epidermal cells were enlarged as compared to healthy leaves, whereas the size of guard cells was reduced. In chlorotic leaves, bundle sheaths were enlarged and appeared disorganized, while the mesophyll was more compacted and less porous than in green leaves. In contrast to healthy leaves, chlorotic leaves of both species showed a significant transient opening of stomata after leaf abscission (Iwanoff effect), which can be ascribed to changes found in epidermal and guard cells. Results indicate that Fe-deficiency may alter the barrier properties of the leaf surface, which can significantly affect leaf water relations, solute permeability and pest and disease resistance.This study was supported by the Spanish Ministry of Science and Education (MEC, grants AGL2006-01416 and AGL2007-61948, co-financed with FEDER), the European Commission (ISAFRUIT project, Thematic Priority 5-Food Quality and Safety of the 6th Framework Programme of RTD; Contract no. FP6-FOOD-CT-2006-016279) and the Aragón Government (group A03). V.F. was supported by a “Juan de la Cierva”-MEC post-doctoral contract, co-financed by the European Social Fund. T.E. was supported by the CAI Europa XXI for a short term stay at the EEAD-CSIC.Peer reviewe

Avaliação da tolerância à clorose férrica de porta-enxertos de citrinos em solução nutritiva

4 Pags.- 3 Figs.Um dos principais factores indutores da clorose férrica em solos calcários é o ião bicarbonato cuja acção parece afectar diversos processos metabólicos nas raízes e nas folhas, diminuindo a disponibilidade de Fe no interior da planta. Nestas condições, quando a absorção de Fe é baixa, os genótipos Fe-eficientes desencadeiam mecanismos de resposta ao nível da parte aérea e/ou radicular que incluem alterações fisiológicas, bioquímicas e morfológicas (Schmidt, 1999). Ao nível da parte aérea, o ferro é um elemento essencial para a formação das membranas dos tilacóides e para a biossíntese clorofilina (Abadía, 1992). Consequentemente, a eficiência de conversão da energia fotossintética é afectada pela clorose férrica e pode ser avaliada pelos parâmetros de fluorescência da clorofila a (Abadía et al., 1999). Neste ensaio em solução nutritiva pretendeu-se caracterizar a tolerância de três porta-enxertos de citrinos à clorose férrica com base em diversos parâmetros e processos fisiológicos da planta.Peer reviewe

Aplicación de técnicas de microscopía a la determinación de cambios anatómicos derivados del déficit de hierro en Medicago truncatula

El hierro (Fe) es un micronutriente esencial para la vida de las plantas, y el cuarto elemento más abundante de la corteza terrestre. Sin embargo, la deficiencia de Fe es uno de los factores más limitantes de la producción agrícola, especialmente en suelos calizos. En condiciones de deficiencia de Fe las plantas como Medicago truncatula desarrollan una serie de cambios adaptativos a nivel fisiológico, morfológico y metabólico. Estudios previos en esta especie mostraron que la deficiencia de Fe induce alteraciones en la abundancia de proteínas de la ruta de los fenilpropanoides de la cual deriva la lignina. En este trabajo se utilizaron distintas técnicas de microscopía tanto óptica como de fluorescencia para identificar posibles modificaciones en la lignificación en esta especie como respuesta a la deficiencia de Fe con o sin la presencia de carbonato de calcio (CaCO3) en el medio. Cortes de raíz, tallo y peciolo se estudiaron mediante microscopía de autoflourescencia, y con las tinciones de safranina, fluoroglucinol y Johansen. La tinción con fluoroglucinol y la autofluorescencia en general resultaron adecuadas para evaluar los cambios en la lignificación. Los tejidos nuevos como raíz y peciolo crecidos durante el periodo de deficiencia de Fe, mostraron una reducción de la lignificación. Por el contrario, cuando la deficiencia de Fe fue acompañada de CaCO3 se observó un aumento de la lignificación del peciolo

Accumulation and secretion of coumarinolignans and other coumarins in Arabidopsis thaliana roots in response to iron deficiency at high pH

22 Pags.- 3 Tabls.- 8 Figs. This Document is Protected by copyright and was first published by Frontiers (http://journal.frontiersin.org/journal/373). All rights reserved. it is reproduced with permission.Root secretion of coumarin-phenolic type compounds has been recently shown to be related to Arabidopsis thaliana tolerance to Fe deficiency at high pH. Previous studies revealed the identity of a few simple coumarins occurring in roots and exudates of Fe-deficient A. thaliana plants, and left open the possible existence of other unknown phenolics. We used HPLC-UV/VIS/ESI-MS(TOF), HPLC/ESI-MS(ion trap) and HPLC/ESI-MS(Q-TOF) to characterize (identify and quantify) phenolic-type compounds accumulated in roots or secreted into the nutrient solution of A. thaliana plants in response to Fe deficiency. Plants grown with or without Fe and using nutrient solutions buffered at pH 5.5 or 7.5 enabled to identify an array of phenolics. These include several coumarinolignans not previously reported in A. thaliana (cleomiscosins A, B, C, and D and the 5′-hydroxycleomiscosins A and/or B), as well as some coumarin precursors (ferulic acid and coniferyl and sinapyl aldehydes), and previously reported cathecol (fraxetin) and non-cathecol coumarins (scopoletin, isofraxidin and fraxinol), some of them in hexoside forms not previously characterized. The production and secretion of phenolics were more intense when the plant accessibility to Fe was diminished and the plant Fe status deteriorated, as it occurs when plants are grown in the absence of Fe at pH 7.5. Aglycones and hexosides of the four coumarins were abundant in roots, whereas only the aglycone forms could be quantified in the nutrient solution. A comprehensive quantification of coumarins, first carried out in this study, revealed that the catechol coumarin fraxetin was predominant in exudates (but not in roots) of Fe-deficient A. thaliana plants grown at pH 7.5. Also, fraxetin was able to mobilize efficiently Fe from a Fe(III)-oxide at pH 5.5 and pH 7.5. On the other hand, non-catechol coumarins were much less efficient in mobilizing Fe and were present in much lower concentrations, making unlikely that they could play a role in Fe mobilization. The structural features of the array of coumarin type-compounds produced suggest some can mobilize Fe from the soil and others can be more efficient as allelochemicals.Work supported by the Spanish Ministry of Economy and Competitiveness (MINECO) (grant AGL2013-42175-R, co-financed with FEDER) and the Aragón Government (group A03). PS-T and AL-V were supported by MINECO-FPI contracts.Peer reviewe