ReDivia - Repositorio Digital de l'Instit Valencià d'Investigacions Agràries
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Actas de Horticultura
Get PDFLa producción de planta ornamental tiene una larga tradición en las regiones mediterráneas españolas, a las que hay que añadir tanto Galicia como las Islas Canarias. La Comunidad Valenciana aglutina alrededor del 31% de la superficie de planta ornamental nacional y en extensión cultivada solo es superada por Cataluña. Sin embargo es la región con mayor vocación exportadora. El 28% del volumen económico nacional que origina la planta viva procede de la Comunidad Valenciana, muy superior al 20% que aporta Andalucía y el 18% de Cataluña (FEPEX, 2014). Aunque las condiciones económicas de las últimas dos décadas han sido favorables al desarrollo del sector y con ello se ha propiciado grandes mejoras en las instalaciones de los viveros, en el momento actual, los productores se enfrentan a la necesidad de equilibrar los costes derivados de su estructura productiva con la incertidumbre de los mercados, es decir, necesitan tener unos ingresos mínimos que no siempre pueden mantener ni asegurar. El objetivo del trabajo es detectar los aspectos técnicos y comerciales que explicarían la evolución del sector ornamental en la Comunidad Valenciana para poder determinar sus puntos fuertes y débiles. Para ello, y de forma complementaria a los datos estadísticos disponibles, se han revisado los aspectos técnicos y agronómicos que condicionan en mayor medida la producción ornamental, y tras mantener reuniones con agentes del sector, se ha elaborado una matriz DAFO de los viveros valencianos. En ella queda constancia los aspectos internos (debilidades y fortaleza), y los aspectos externos (amenazas y oportunidades), referidos tanto a la faceta productiva como comercial
Diversity of floral regulatory genes of japonica rice cultivated at northern latitudes
Get PDFBackground: Rice is considered a short day plant. Originally from tropical regions rice has been progressively adapted to temperate climates and long day conditions in part by modulating its sensitivity to day length. Heading date 3a (Hd3a) and RICE FLOWERING LOCUS T 1 (RFT1) that code for florigens, are known as major regulatory genes of floral transition in rice. Both Hd3a and RFT1 are regulated by Early heading date 1 (Ehd1) and Days to heading on chromosome 2 (DTH2) while Heading date 1 (Hd1) also governs Hd3a expression. To investigate the mechanism of rice adaptation to temperate climates we have analyzed the natural variation of these five genes in a collection of japonica rice representing the genetic diversity of long day cultivated rice. Results: We have investigated polymorphisms of Hd3a, RFT1, Ehd1, Hd1 and DTH2 in a collection of 57 japonica varieties. Hd3a and RFT1 were highly conserved, displaying one major allele. Expression analysis suggested that RFT1 rather than Hd3a could be the pivotal gene controlling flowering under long day conditions. While few alleles were found in the Ehd1 promoter and DTH2 coding region, a high degree of variation in Hd1, including non-functional alleles, was observed. Correlation analysis between gene expression levels and flowering periods suggested the occurrence of other factors, additionally to Ehd1, affecting RFT1 regulation in long day adapted cultivars. Conclusions: During domestication, rice expansion was accompanied by changes in the regulatory mechanism of flowering. The existence of non-functional Hd1 alleles and the lack of correlation of their presence with flowering times in plants grown under long day conditions, indicate a minor role of this branch in this process and the existence of an alternative regulatory pathway in northern latitudes. Expression analysis data and a high degree of conservation of RFT1 suggested that this gene could be the main factor regulating flowering among japonica cultivars adapted to northern areas. In the absence of inhibition exerted by Hd1 through repression of Hd3a expression, the role of Ehd1 as a regulator of RFT1 and Hd3a appears to be reinforced. Data also indicated the occurrence of additional regulatory factors controlling flowering
Unravelling bacteriophage phi 11 requirements for packaging and transfer of mobile genetic elements in Staphylococcus aureus
Get PDFBacteriophages play a major role in spreading mobile genetic elements (MGEs)-encoded genes among bacterial populations. In spite of this, the molecular requirements for building phage transducing particles have not been completely deciphered. Here, we systematically inactivated each ORF from the packaging and lysis modules of the staphylococcal phage phi 11, used as a model for the Siphoviridae phages infecting Gram-positive bacteria, and determined their functional role in transferring different MGEs including plasmids, staphylococcal pathogenicity islands (SaPIs) and the phage itself. In a previous report, we identified seven of these ORFs as being required for the production of functional phage or SaPI particles. In this report, we have completed the mutational analysis and have identified and characterized 15 additional phage-encoded proteins required for the production of mature phage, SaPI, or transducing particles. Apart from these, we have not yet ascertained any specific function for the six remaining phi 11 genes, though they are highly conserved among the staphylococcal bacteriophages. To the best of our knowledge, this study represents the first systematic deletion analysis of all the ORFs comprising the morphogenetic and lysis modules of a phage, clearly defining the molecular requirements involved in phage-mediated MGEs transfer
Inheritance of Rootstock Effects and Their Association with Salt Tolerance Candidate Genes in a Progeny Derived from 'Volkamer' Lemon
Get PDFA seedling population from hybrids between ‘Volkamer’ lemon (Citrus volkameriana) and ‘Rubidoux’ trifoliate orange (Poncirus trifoliata) was grafted with ‘Hashimoto’ Satsuma mandarin (Citrus unshiu) to study the inheritance of rootstock effects on salt tolerance in terms of fruit yield. Trees were maintained in a screenhouse, and a salt treatment (25 mm NaCl) was applied to 32 genotypes from June to September every year for 5 years. Rootstocks were genotyped for five salt tolerance candidate genes. Significant effects of rootstock genotype (G) and treatment (E) were found for most traits. Salinity decreased yield and juice volume but improved soluble solids concentration (TSS) and rind thickness. Year effects were highly significant in most cases. G × E interactions were found for fruit weight, total fruit weight, juice volume (JV), leaf water content (LWC), and leaf [Na+]. Therefore, rootstocks that induce early fruit maturation under salinity (by increasing TSS and maintaining JV) can be selected to expand the harvesting calendar of mandarin cultivars. Salt tolerance candidate genes SOS1 and NHX1 were associated with fruit yield traits under normal conditions (1.4 dS·m−1), and SOS1 and CCC were associated with LWC under salinity conditions (4 dS·m−1). Only 5% progeny induced higher accumulated yield than ‘Volkamer’ lemon under salinity. Given the low heritability of rootstock effects on fruit yield under salinity conditions (0.18 at most), marker-assisted selection might be useful
Epigenetic regulation of bud dormancy events in perennial plants
Get PDFRelease of bud dormancy in perennial plants resembles vernalization in Arabidopsis thaliana and cereals. In both cases, a certain period of chilling is required for accomplishing the reproductive phase, and several transcription factors with the MADS-box domain perform a central regulatory role in these processes. The expression of DORMANCY-ASSOCIATED MADS-box (DAM)-related genes has been found to be up-regulated in dormant buds of numerous plant species, such as poplar, raspberry, leafy spurge, blackcurrant, Japanese apricot, and peach. Moreover, functional evidence suggests the involvement of DAM genes in the regulation of seasonal dormancy in peach. Recent findings highlight the presence of genome-wide epigenetic modifications related to dormancy events, and more specifically the epigenetic regulation of DAM-related genes in a similar way to FLOWERING LOCUS C, a key integrator of vernalization effectors on flowering initiation in Arabidopsis. We revise the most relevant molecular and genomic contributions in the field of bud dormancy, and discuss the increasing evidence for chromatin modification involvement in the epigenetic regulation of seasonal dormancy cycles in perennial plants
Usefulness of stem dendrometers as continuous indicator of loquat trees water status
No full textPostharvest regulated deficit irrigation (RDI) is an effective strategy to hasten flowering and harvest in loquat (Eriobotrya japonica Lindl.) trees, which in the Mediterranean countries has been related to an increase in the economic return. The success of an RDI strategy, however, depends on the duration and severity of the water stress reached by the trees. When RDI is applied, then, it is important to regularly monitor the plant water status. The measurement of the trunk diameter variations by means of stem dendrometers, which can be automated to remotely determine the plant water status, is a proven method for many fruit trees. In loquat, however, its use has not been yet assessed. In this experiment performed in a loquat orchard planted with the cv. 'Cardona' during the summer of 2009, the suitability of using stem dendrometers to detect plant water stress was assessed by taking measurements in fully irrigated and trees subjected to a drought cycle of 47 days. Results showed that at the beginning of the drought cycle period there was an increase in the maximum daily trunk shrinkage (MDS) in non-irrigated trees even before that clear differences in stem water potential (Psi(s)) could be detected between treatments. However, when plant water stress became more severe (Psi(s) lower than -1.4 MPa), MDS did not increase further. The maximum trunk diameter (MXTD) evolution in control trees showed a steadily increase in trunk growth during the whole experimental period. In non-irrigated trees, however, MXTD remained stable until the end of the treatment when irrigation was resumed. The Psi(s) was the most sensitive indicator to water stress due to its very low tree-to-tree variability in comparison with the other indicators. Overall results show that trunk diameter variations have some limitations to monitor plant water status in loquat RDI orchards and therefore new alternatives should be explored. (C) 2014 Elsevier B.V. All rights reserved
Effect of a low oxygen atmosphere combined with 1-MCP pretreatment on preserving the quality of 'Rojo Brillante' and 'Triumph' persimmon during cold storage
No full textFor the purpose of prolonging the storage of ‘Rojo Brillante’ and ‘Triumph’, the main persimmon varieties cultivated in Spain, the effect of a controlled atmosphere based on 4–5% O2 + N2, applied alone or in combination with 1-MCP pretreatment, was evaluated herein after storage at 1 °C for up to 90 days and subsequent simulated shelf life conditions at 20 °C. Our results showed for the first time that ‘Triumph’, a cultivar hitherto considered insensitive to chilling injury when cultivated under Spanish conditions, manifests flesh gelling and drastic fruit softening during cold storage, both of which are important symptoms of chilling injury in persimmon. ‘Rojo Brillante’ and ‘Triumph’ fruit showed different responses to the controlled atmosphere (CA) conditions studied. For ‘Rojo Brillante’, the combination of CA and 1-MCP pretreatment substantially alleviated chilling injury (flesh softening and gelling). However, all the fruit stored under CA, pretreated with 1-MCP or not, manifested internal flesh browning. For ‘Triumph’ fruit, the combined use of 1-MCP pretreatment and CA storage retarded fruit softening and markedly alleviated flesh gelling. This treatment was not associated with manifestations of internal disorders, and helped extend the storage period up to 90 d, plus 5 d at 20 °C. CA-exposed fruit also displayed considerably fewer black spots caused by Alternaria alternata. Therefore, although the 1-MCP pretreatment and CA storage combination based on 4–5% O2 + N2 must be considered a useful technology to prolong the storage of ‘Triumph’ as it preserves internal and external fruit quality, it is necessary to optimise the appropriate CA storage conditions for ‘Rojo Brillante’
Genetic variation and diversity among loquat accessions
No full textLoquat (Eriobotrya japonica (Thunb.) Lindl., Maloideae, Rosaceae) is a subtropical evergreen fruit tree indigenous of China, where the center of origin of the species is located. Loquat is grown in all subtropical areas and was introduced in the Mediterranean basin in late eighteenth century. In Europe, the largest germplasm bank is located at Instituto Valenciano de Investigaciones Agrarias (IVIA; Valencia, Spain). Thirteen microsatellites and a conserved region of S-allele were used to assess the genetic diversity of 102 accessions of the IVIA collection. A total of 38 SSR alleles and 11 putative S-alleles were used to study the genetic structure of the loquat germplasm bank using the STRUCTURE software, Factorial Correspondence Analysis (FCA), and unweighted pair-group method (UPGMA) cluster analyses. The total diversity was H T = 0.5682, the genetic differentiation G ST = 0.1660, and the standardized G ST reached a much higher value of G′ST = 0.4948. The Evanno’s test indicated that the most informative number of populations was five, with accessions distributed according to their geographic origin in two, one, and two groups of Spanish, Italo-Spanish, and non-European origin, respectively. Knowledge of the substructure and diversity of the IVIA loquat collection and the self-incompatibility genotype data will allow us to select and incorporate useful materials into the loquat breeding program
Can we forecast the effects of climate change on entomophagous biological control agents?
No full textThe worldwide climate has been changing rapidly over the past decades. Air temperatures have been increasing in most regions and will probably continue to rise for most of the present century, regardless of any mitigation policy put in place. Although increased herbivory from enhanced biomass production and changes in plant quality are generally accepted as a consequence of global warming, the eventual status of any pest species will mostly depend on the relative effects of climate change on its own versus its natural enemies' complex. Because a bottom-up amplification effect often occurs in trophic webs subjected to any kind of disturbance, natural enemies are expected to suffer the effects of climate change to a greater extent than their phytophagous hosts/preys. A deeper understanding of the genotypic diversity of the populations of natural enemies and their target pests will allow an informed reaction to climate change. New strategies for the selection of exotic natural enemies and their release and establishment will have to be adopted. Conservation biological control will probably become the keystone for the successful management of these biological control agents. (c) 2013 Society of Chemical Industr