Iron deficiency enhances the levels of ascorbate, glutathione, and related enzymes in sugar beet roots

The effects of Fe deficiency stress on the levels of ascorbate and glutathione, and on the activities of the enzymes ferric chelate reductase, glutathione reductase (EC 1.6.4.2), ascorbate free-radical reductase (EC 1.6.5.4) and ascorbate peroxidase (EC 1.11.1.11), have been investigated in sugar beet (Beta vulgaris L.) roots. Plasma membrane vesicles and cytosolic fractions were isolated from the roots of the plants grown in nutrient solutions in the absence or presence of Fe for two weeks. Plants responded to Fe deficiency not only with a 20-fold increase in root ferric chelate reductase activity, but also with moderately increased levels of the general reductants ascorbate (2-fold) and glutathione (1.6-fold). The enzymes of the ascorbate-glutathione cycle in roots were also affected by Fe deficiency. Glutathione reductase activity was enhanced 1.4-fold with Fe deficiency, associated to an increased ratio of reduced to oxidized glutathione, from 3.1 to 5.2. The plasma membrane fraction from iron-deficient roots showed 1.7-fold higher ascorbate free-radical reductase activity, whereas in the cytosolic fraction the enzyme activity was not affected by Fe deficiency. The activity of the cytosolic hemoprotein ascorbate peroxidase decreased approximately by 50% with Fe deprivation. These results show that sugar beet responds to Fe deficiency with metabolic changes affecting components of the ascorbate-glutathione cycle in root cells. This suggests that the ascorbate-glutathione cycle would play certain roles in the general Fe deficiency stress responses in strategy I plants.The work was supported by grants PB97-1176 from the Dirección General de Investigación Científica y Técnica and AIR3-CT94-1973 from the Commission of European Communities to J.A. T.Z. was supported by a sabbatical grant (SAB95-0551) from the Spanish Ministry of Science and Education.Peer Reviewe

Dynamics of metabolic responses to iron deficiency in sugar beet roots

This study presents information on the dynamics of sugar beet (Beta vulgaris L.) root metabolic responses to Fe deficiency. Four days after Fe withdrawal from the nutrient solution, the concentration of reduced glutathione (GSH) and the activities of ferric chelate reductase (FC-R, E.C. 1.6.99.13) and ascorbate peroxidase (APX, E.C. 1.11.1.11) showed marked differences with the control values. The differences in root fresh weight, the concentrations of ascorbate (Asc) and soluble proteins, and proton release rates by roots became more prominent after the first week. Time course kinetics of FC-R activity and proton extrusion showed induction maxima, followed by rapid declines with the progress of Fe deficiency. The time courses of root Asc and GSH concentrations showed gradual increases with the advancement of Fe deficiency suggesting that plant responses to Fe deficiency stress may include a shift in the redox balance inside the root cells towards more reduced state. Data imply that an alternative Asc-dependent Fe reduction may become important with the advancement of Fe deficiency stress, when FC-R activity is declining. The time course of APX activity reveals that it could be a sensitive indicator of the initial changes in the plant Fe nutritional status.Work supported by grant BOS2001-2343 from the Spanish Ministry of Science and Technology to J.A. T.Z. was supported by a sabbatical grant (SAB95-0551) from the Spanish Ministry of Science and Education.Peer Reviewe

Caracterización ampelográfica y molecular de variedades tintas de vid antiguas y sin catalogar de Aragón

3 Pag., 4 Fot.Las variedades y ecotipos autóctonos en desuso recuperados en zonas marginales, son un potencial genético susceptible de ser empleado tanto en procesos de mejora como en la comercialización para la creación de nuevos caldos y pueden constituir la base de una respuesta competitiva y sostenible a algunos de los efectos del cambio climático, así como a los desafíos del mercado. El interés del estudio radica en tener disponible un material genético de utilidad en el futuro, adelantándose a las posibles fluctuaciones de mercado y/o efectos adversos producidos por el cambio climáticoProyecto de la Acción estratégicade Conservación de Recursos Genéticos de interés agroalimentario. INIA: RF02-004-C5-5 Sub.5 “Recuperación y caracterización de variedades de vid en peligro de extinción en la mitad norte de España”.Peer reviewe

Genetic control and location of QTLs involved in antioxidant capacity and fruit quality traits in peach [Prunus persica (L.) Batsch]

7 Pags., 1 Tabl., 2 Figs. The definitive version is available at: http://www.actahort.org/index.htmIn peach fruits, phenolic compounds serve as a major source of potential antioxidants which are known to play a significant role in fruit quality and in human well being. This study was conducted in a F1 population derived from the cross ‘Venus’ × ‘Big Top’ nectarines in order to investigate the variability in the fruit antioxidant content and to study the genetic control and location of QTLs involved in fruit quality traits. Biochemical analyses have been performed to measure L-ascorbic acid (vitamin C), total phenolics, flavonoids, anthocyanins contents and antioxidant capacity.This study was funded by the Spanish MIC1NN (Ministry of Science and Innovation) grant AGL-2008-00283, cofunded by FEDER, and the Regional Government of Aragon (A44). W. Abidi was supported by a JAE fellowship from CSIC (Consejo Superior de Investigaciones Científicas).Peer reviewe

Preservation and Molecular Characterization of Ancient Varieties in Spanish Grapevine Germplasm Collections

6 Pag., 3 Tabl.Two hundred accessions from the Movera Grapevine Germplasm Bank in Aragón, Spain, were examined. Molecular profiles at six SSR loci allowed confirmation of the trueness-to-type of 86 accessions, correct names were assigned to 33 misnamed accessions, and 43 "unknown" accessions were identified. Thirty-eight accessions, which gave 24 molecular profiles, may be regarded as belonging to autochthonous varieties. Results offer new SSR allelic profiles of ancient Spanish varieties to form part of the genetic heritage of grapevine and reveal the existence of some synonymies, homonymies, and discrepancies in the published database from the El Encín Grapevine Germplasm Bank in Madrid, Spain.This work was supported by the Spanish Institute for Agricultural Research grant RF02-004-C5-5; Regional Government of Aragón grant A44 and grant CONSID-DGA, PM071/2007; and Spanish Ministry of Science and Innovation grant AGL-2008-00283, cofunded by FEDER.Peer reviewe

Development of an SSR-based identification key for Tunisian local almonds

19 Pags., 4 Figs., 2 Tabls.Ten simple sequence repeat (SSR) loci were used to study polymorphism in 54 almond genotypes. All genotypes used in this study originated from almond-growing areas in Tunisia with different climatic conditions ranging from the sub-humid to the arid and are preserved in the national collection at Sidi Bouzid. Using ten SSR, 130 alleles and 250 genotypes were revealed. In order to develop an identification key for each accession, the data were analysed separately for each microsatellite marker. The most polymorphic microsatellite (CPDCT042) was used as a first marker. Two microsatellite loci (CPDCT042 and CPDCT025) were sufficient to discriminate among all accessions studied. Neighbour-joining clustering and principal coordinate analysis were performed to arrange the genotypes according to their genetic relationships and origin. The results are discussed in the context of almond collection management, conformity checks, identification of homonyms, and screening of the local almond germplasm. Furthermore, this microsatellite-based key is a first step toward a marker-assisted identification almond database.Financial support was provided in part by the Tunisian Ministry of Higher Education, Scientific Research and Technology, the Spanish Ministry of Science and Innovation (AGL2008-00283/AGR co-financed by FEDER), the Aragon Government (Group A44), and the Agencia Española de Cooperación Internacional (A/5339/06 and A/8334/07).Peer reviewe