Chloride regulates leaf cell size and water relations in tobacco plants

19 páginas.-- 9 figuras.-- 5 tablas.-- 77 referencias.-- Supplementary Data: Supplementary_figures_S1_S7___Tables_S1_S7.pdfChloride (Cl–) is a micronutrient that accumulates to macronutrient levels since it is normally available in nature and actively taken up by higher plants. Besides a role as an unspecific cell osmoticum, no clear biological roles have been explicitly associated with Cl– when accumulated to macronutrient concentrations. To address this question, the glycophyte tobacco (Nicotiana tabacum L. var. Habana) has been treated with a basal nutrient solution supplemented with one of three salt combinations containing the same cationic balance: Cl–-based (CL), nitrate-based (N), and sulphate+phosphate-based (SP) treatments. Under non-saline conditions (up to 5mM Cl–) and no water limitation, Cl– specifically stimulated higher leaf cell size and led to a moderate increase of plant fresh and dry biomass mainly due to higher shoot expansion. When applied in the 1–5mM range, Cl– played specific roles in regulating leaf osmotic potential and turgor, allowing plants to improve leaf water balance parameters. In addition, Cl– also altered water relations at the whole-plant level through reduction of plant transpiration. This was a consequence of a lower stomatal conductance, which resulted in lower water loss and greater photosynthetic and integrated water-use efficiency. In contrast to Cl–, these effects were not observed for essential anionic macronutrients such as nitrate, sulphate, and phosphate. We propose that the abundant uptake and accumulation of Cl– responds to adaptive functions improving water homeostasis in higher plants.This work was supported by the Spanish Ministry of Science and Innovation-FEDER grant AGL2009-08339/AGR. The help, expertise, and technical assistance of C. Rivero, A. Vázquez, S. Luque, B.J. Sañudo, F.J. Durán, Y. Pinto, and J. Espartero are gratefully acknowledged. We would like to extend our gratitude to the valuable reviews and contributions by the anonymous referees and the editor, Timothy Colmer, which helped us to improve the manuscript substantially.Peer reviewe

Chloride Nutrition Regulates development, Water Balance and Drought Resistance in Plants

6 páginas.-- 5 figuras.-- 9 referencias.-- Poster presentado en el XII Luso-Spanish Symposium on Plant Water Relations – Water to Feed the World. 30th of September – 3rd of October (Evora) PortugalCl- is a strange micronutrient since actual Cl- concentration in plants is about two orders of magnitude higher than the content required as essential micronutrient. This accumulation requires a high cost of energy, and since Cl- is a major osmotically active solute in the vacuole, we propose that Cl- plays a role in the regulation of water balance in plants. We show here that, when accumulated to macronutrient levels, Cl- specifically regulates leaf cell elongation and water balance parameters, improving water relations at both the leaf tissue and the whole plant levels, increasing drought resistance in higher plants.This work was supported by the Spanish Ministry of Science and Innovation-FEDER grant AGL2009-08339/AGR.Peer Reviewe

Identificación inequívoca de variedades de cítricos mediante comparación genómica

Ibáñez, Victoria et al.-- 9 páginas, 7 figuras, 2 referencias.En los últimos años, el uso de marcadores moleculares que identifican cambios polimórficos a nivel del ADN, está jugando un papel cada vez mayor en las aplicaciones biotecnológicas de todo tipo así como en los estudios básicos de genética. Sin embargo, todos los esfuerzos realizados hasta la fecha para discriminar variedades de cítricos próximas y, en particular, variedades derivadas por mutaciones espontáneas e inducidas, han resultado infructuosos. En este contexto, el consorcio CITRUSEQ formado por 3 instituciones públicas, el Instituto Valenciano de Investigaciones Agrarias, el IRNASE del Consejo Superior de Investigaciones Científicas y la Fundación Centro de Investigación Príncipe Felipe y 6 entidades privadas: Eurosemillas, S.L., Investigación Citrícola Castellón S.A., Anecoop, Special Newfruit Licensing Mediterraneo S.L., GMC Variedades Vegetales A.I.E y Fundación Ruralcaja está desarrollando un número considerable de aplicaciones biotecnológicas basadas en el conocimiento del genoma de los cítricos entre las que se incluyen protocolos y procedimientos de identificación inequívoca de especies y variedades de agrios. En este artículo describimos la estrategia de detección y validación de marcadores de ADN derivados de la comparación genómica que permiten mediante análisis de PCR la discriminación rápida, eficaz y asequible de variedades comerciales generadas por mutaciones espontáneas e inducidas.Esta investigación ha sido financiada por el Consorcio Citruseq y el Ministerio de Ciencia e Innovación a través de los proyectos PSE-060000-2009-8 y IPT- 010000-2010-43 y el Fondo Europeo de Desarrollo Regional.Peer Reviewe

Sequencing of 150 Citrus Varieties: Linking Genotypes to Phenotypes

5 páginas. 2 tablas.-- 3 referencias.-- Artículo publicado en el XII International Citrus Congress.-- Terol, Javier et al...Elucidation of genomic sequences is an essential and necessary first step to identify genetic variants associated with agronomic traits of interest. The Citruseq Consortium, a joint effort developed by public institutions and private companies has sequenced the genomes of 150 citrus varieties with the Illumina platform at high average coverage. Paired end genomic DNA libraries of 100 (2x) bp reads and with an average insert size of 500 bp were constructed. The haploid genome of Citrus clementine (www.phytozome.com) was used as reference genome. More than 150 Citrus genomes including rootstocks and species of mandarins, oranges, lemons, grapefruits and limes were sequenced. The consortium also generated a web portal that allows searching and sequence comparisons among approximately 8 million of gene variants and 45 billion of base pairs. Initial analyses suggest that the stored information can help unravel fundamental aspects of biological and evolutionary interest such as the origin of citrus. From the commercial standpoint this information may help to authenticate varieties, to improve marker-assisted breeding and to identify genes of major agronomic interest.This work was funded by the Spanish Ministerio de Ciencia e Innovación PSE-060000-2009-8 and IPT-010000-2010-43 grants. We would like to thank Elena Blazquez,Angel Boix, Juan Vicente Muñoz, Matilde Sancho and Isabel Sanchis for his invaluable help in field and laboratory tasks.Peer reviewe

Citrus Genomics and Breeding: Identification of Candidate Genes by the Use of Mutants and Microarrays

The survival of the citrus industry is critically dependent on genetically superior cultivars. Improvements in these traits through traditional techniques are unfortunately extremely difficult due to the unusual combination of biological characteristics of citrus. Genomic science holds promise of improvements in breeding and the main goal of our group is to develop genomics tools for the generation of new genotypes. We pursue the identification of candidate genes, alleles and genotypes improving citrus fruit quality and performance, correlating phenotypic analyses, metabolic profiling and gene expression. At completion, genes and alleles with major functions in nutritional quality and stress tolerance could be selected and genotypes with improved fruit composition searched among existing or generated collections. This goal is supported by two complementary strategies the identification of genes of agricultural interest by the use of mutants and microarrays and the elucidation of the citrus genome sequence. In this communication the efforts we are developing in this first approach are revised while the other strategy will be resumed elsewherePeer Reviewe

Citruseq: una aproximación genómica a la mejora de los cítricos

La mejora de los cultivos cítricos en general está muy mermada debido entre otros obstáculos a la combinación tan inusual de características reproductivas y biológicas que tienen lugar en los cítricos. Las aproximaciones genómicas, por otro lado, permiten vislumbrar desarrollos biotecnológicos que podrían facilitar o al menos acortar los periodos de mejora en este cultivo. En este contexto, el Centro de Genómica del Instituto Valenciano de Investigaciones Agrarias (IVIA), está desarrollando la propuesta Citruseq, un proyecto de colaboración público-privado, liderado por la Fundación Ruralcaja Grupo CRM,, en el que también intervienen otras instituciones públicas como el Instituto de Recursos Naturales y Agrobiología de Sevilla (IRNAS, CSIC) y la Fundación de la Comunidad Valenciana Centro de Investigación Príncipe Felipe (CPF), y cinco empresas del sector cítricola español como Eurosemillas, S.L., Investigación Citrícola Castellón S.A., Anecoop S. Coop., Special Newfruit Licensing Mediterraneo S.L. / Citrus Genesis S.L., y GCM Variedades Vegetales. La propuesta Citruseq, que lleva por título ¿Secuenciación, genotipado, y desarrollo de herramientas genómicas para la mejora de cítricos ¿está financiada por el Ministerio de Ciencia e Innovación a través de los Proyectos Singulares y Estratégicos y por las entidades privadas del propio consorcio. Uno de los objetivos principales del proyecto es la dilucidación de la secuencia del genoma de las variedades de cítricos más importantes de la citricultura española, información que en definitiva permitirá la identificación de genes responsables de la calidad y de la producción. Otro de los objetivos fundamentales de la propuesta es la generación directa de nuevas variedades mediante metodologías de irradiación e hibridación. El proyecto dedica además un gran esfuerzo al desarrollo de herramientas biotecnológicas que aceleren la obtención y autentificación de variedades.Esta investigación está financiada por el Ministerio de Ciencia e Innovación a través del proyecto CITRUSEQ, PSE-060000-2009-8.Peer Reviewe

Fundamentos y aplicaciones posibles de la genómica de cítricos

16 páginas, 8 figuras, 18 referencias.En resumen, la tecnología genómica está poniendo al servicio de la citricultura una batería de herramientas moleculares que en su conjunto poseen una gran capacidad para obtener información y un potencial amplio para mejorar productos actuales o producir nuevas selecciones de cítricos de interés comercial. Algunas de estas herramientas son la hibridación de micromatrices de ADNc de cítricos. La adquisición y la utilización de estas tecnologías en la Comunidad Valenciana permitirán generar el conocimiento teórico– práctico necesario para optimizar el cultivo de los cítricos.Peer reviewe

Aplicaciones de la Genómica al estudio de la biología de los cítricos y del arroz, dos especies de interés agronómico en la Comunidad Valenciana

[EN]: Biotechnology is currently offering to Agriculture a broad set of reliable and powerful molecular tools that could lead to a revolution of the crop cultures. The knowledge and use of these technologies will allow us to generate the theoretical and practical background needed to optimize the culture, yield and quality of the crops. With this purpose, the Valencian Institute for Agricultural Research (IVIA) has created the Genomics Center. A wide range of physiological, biochemical, molecular and genomic techniques are being developed in this center in order to study the Biology of citrus and rice, two species of major interest in the Valencian Community.[ES]: La biotecnología actual ha puesto al servicio de la Agricultura una batería de herramientas moleculares fiables y muy poderosas, que pueden revolucionar el cultivo de las especies de interés agrícola tal como lo entendemos en la actualidad. La adquisición y la utilización de estas tecnologías nos permitirá generar el conocimiento teórico-práctico necesario para optimizar el cultivo, producción y calidad de los productos actuales. Con este fin, el Instituto Valenciano de Investigaciones Agrarias ha creado el Centro de Genómica. En este Centro se desarrolla un amplio abanico de técnicas de fisiología, bioquímica, biología molecular y genómica con el objetivo de estudiar la biología del arroz y de los cítricos, dos especies de interés agrícola en la Comunidad Valenciana.Peer Reviewe

Changes in transcriptional profiles of mature and immature citrus leaves acclimated to salinity

Poster presentado en the XII International Citrus Congress. Valencia, Spain 18th–23rd November 2012While the molecular response of salinized plants in the short-medium term (hours-days) has been broadly studied, the knowledge about the nature of the genes involved in maintaining homeostatic conditions the long term (months-years) has remained elusive. With this aim, we have analyzed the transcriptome of leaves from citrus plants acclimated to moderate salinity (2 years with NaCl 30 mM). Through functional genomics, using the 7K cDNA chip from ¿Consorcio Valenciano de Genómica Funcional de Cítricos¿, the transcriptome of citrus plants acclimatized to salinity was analyzed in mature leaves (8 months) and immature leaves (2 months). Although immature leaves accumulated low levels of chloride (0.51%±0.06), they exhibited high responsiveness to salinity (1,211 differential-responsive genes) compared with mature leaves, which cumulated higher chloride levels (1.05% ± 0.01), and showed a lower number of differentially-responsive genes (100 genes). Immature leaves induced functional categories that were not induced in mature leaves, like ¿cell wall biosynthesis¿, ¿metabolism¿, ¿defense¿, ¿secretion and membrane traffic¿, ¿water transport¿ and ¿antioxidant activity¿. On the other hand, the degree of coincidence was higher in the group of genes that were repressed by salinity. Both mature and immature leaves repressed genes mostly involved in ¿stress response¿. We highlight how the same plant organ in different developmental stages show huge differences in the amount and nature of genes which are responding to an abiotic stimulus.Peer Reviewe

Chloride nutrition at macronutrient levels regulates plant development, water balance and drought resistance of tobacco plants

Chloride (Cl-) is considered to be a strange micronutrient since actual Cl- concentrations in plants is 10-100 times higher than the content required as essential micronutrient, (Marschner, 1995; Brumós et al, 2010), whereas all the other mineral micronutrients (B, Cu, Fe, Mn, Mo, Ni, Zn) are present at much lower concentrations in plant tissues (1-5 orders of magnitude below). Since Cl- uptake and transport is an energetically expensive process (White and Broadley 2001; Brumós et al, 2010), we propose that Cl-, when accumulated to concentrations typical of the content of a macronutrient, plays a poorly understood biological role, not critical under normal growth conditions. Since Cl- appears to be particularly well suited to accomplish osmoregulatory functions, the proposed biological role could be related to the regulation of water balance at both the cell and the whole plant level. There is little experimental evidence in this regard since: i) it is unclear in which extent Cl- is specifically required to fulfil osmoregulatory roles or whether other anions, like nitrate, phosphate, sulphate, and organic acids can replace chloride in such functions; ii) usually the role of Cl- is not adequately differentiated from that of their accompanying cations; iii) the concepts linking Cl- homeostasis with osmotic/turgor regulation have been frequently discussed in the context of halophyte species and in glycophytes under salt stress conditions (Flowers et al, 1988), what have led to some confusion in the context of Cl- nutrition. We intend to establish the role of Cl- in glycophyte plants when accumulated to macronutrient levels, and we will present results showing that under non-saline conditions (1-5 mM external Cl- concentrations) and no water limitation, Cl- specifically promotes the growth of tobacco plants through mechanisms regulating leaf cell elongation and water relations. Furthermore, under water deficit conditions, Cl--treated plants exhibit drought resistance due to the sum of stress avoidance (reduced estomatal water loss) and tolerance (probably due to higher solute accumulation) mechanisms. - Brumós J., Talón M., Bouhlal R.Y.M. & Colmenero-Flores J.M. (2010) Cl- homeostasis in includer and excluder citrus rootstocks: transport mechanisms and identification of candidate genes. Plant Cell Env, 33, 2012-2027. - Marschner H. (1995) Mineral Nutrition of Higher Plants, 2nd ed. (Second Edition ed.). Academic Press, London. - Flowers T.J. (1988) Chloride as a nutrient and as an osmoticum. In: Advances in plant nutrition (ed L.A. Tinker B), pp. 55-78. Praeger, New York.ENVIRONMENT WORKSHOPS 2013 “GENOMIC, PHYSIOLOGICAL AND BREEDING APPROAHES FOR ENHANCING DROUGHT RESISTANCE IN CROPS ” Baeza, Spain, 23–25 September 2013Peer Reviewe