ReDivia - Repositorio Digital de l'Instit Valencià d'Investigacions Agràries
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Development of SSR markers located in the G1 linkage group of apricot (Prunus armeniaca L.) using a bacterial artificial chromosome library
No full textSixteen simple sequence repeats (SSRs) of apricot (Prunus armeniaca L.) were isolated from a bacterial artificial chromosome (BAC) library. Twelve restriction fragment length polymorphism (RFLP) probes mapped on LG1 of the Prunus general map were hybridized to the BAC library in order to select clones belonging to G1 linkage group of apricot. Selected BACs were digested, subcloned and hybridized with probes containing repeat motifs (GA)(10) and (TA)(10). Sequencing of the positive subclones revealed 18 unique SSR sequences of which 16 allowed the design of primers flanking the SSR. From the 16 primer pairs, 10 amplified polymorphic markers with an average of observed and expected heterozygosities of 0.44 and 0.68, respectively. The procedure described here proves to be a useful technique for obtaining markers in target areas of a genome
A novel RT-PCR approach for detection and characterization of citrus viroids
No full textCitrus plants are natural hosts of five viroid species and a large number of sequence variants. Because of their small size, viroids lend themselves to various RT-PCR approaches for their detection and further characterization. The one-step RT-PCR approach proposed here is based on the synthesis of viroid-cDNA by reverse transcription at 60 degrees C using a viroid specific 27-mer primer followed by standard second strand synthesis plus PCR amplification with various primer pairs. According to the primers used, full or partial length viroid-DNA is obtained. The technique avoids amplicon contamination in routine diagnosis. The Suitability of the technique has been demonstrated using several nucleic acid extraction procedures and different viroid infected host species. The homogenization of tissue inside scaled plastic bags followed by nucleic acid extraction using a SDS/potassium acetate method is recommended because of its efficiency, simplicity and low cost. This extraction procedure, when coupled to the one-step RT-PCR approach, can be useful to avoid cross-contamination during routine diagnosis. A PCR strategy capable of discriminating between mild and severe strains of CEVd and identifying cachexia-inducing isolates of HSVd. is also described
Protección frente a plum pox virus en plantas transgénicas de Nicotiana benthamiana que expresan anticuerpos recombinantes contra proteínas del virus
Get PDFPlum pox virus (PPV) o virus de la sharka produce importantes daños y pérdidas económicas
en frutales de hueso. En este trabajo se propone probar una nueva y prometedora estrategia
de resistencia a la enfermedad de la sharka basada en el uso de anticuerpos recombinantes.
La expresión constitutiva de genes o fragmentos de genes de anticuerpo (anticuerpos recombinantes
o rAbs) específicos de proteínas virales se ha demostrado que puede inmunomodular
o interferir con la infección viral (Tavladoraki y col, 1993). La eficacia de esta estrategia
depende principalmente de la naturaleza del antígeno y/o epítopo reconocido por el fragmento
de anticuerpo recombinante, de la correcta expresión y acumulación del anticuerpo recombinante
y del compartimento celular al que vaya dirigido. El objetivo de este trabajo ha
sido evaluar el efecto sobre la infección viral de la expresión de anticuerpos recombinantes
específicos de proteínas del virus de la sharka en plantas transgénicas de una especie modelo
(Nicotiana benthamiana) como paso previo a su uso en Prunus cuando estos puedan ser
transformados y regenerados con éxito
Cryopreservation of plant germplasm using the encapsulation-dehydration technique: Review and case study on sugarcane
No full textEncapsulation-dehydration is a cryopreservation technique based on the technology developed for producing synthetic seeds, Le. the encapsulation of explants in calcium alginate beads. Encapsulated explants are then precultured in liquid medium with a high sucrose concentration and partially desiccated before freezing. Encapsulating the explants allows the subsequent application of very drastic treatments including preculture with high sucrose concentrations and desiccation to low moisture contents which would be higly damaging or lethal to non-encapsulated samples. An encapsulation-dehydration protocol comprises the following steps: pretreatment, encapsulation, preculture, desiccation, freezing and storage, thawing and regrowth. Encapsulation-dehydration has been applied to around 40 different plant species. The optimization of the successive steps of the encapsulation-dehydration protocol is illustrated for sugarcane apices
Effect of storage temperature on the flavour of citrus fruit
Get PDFThis paper reports the effect of different storage temperatures (5, 15, 20 and 25 degrees C) on the flavour of cv. Valencia Late Frost oranges stored for up to one month (following a pre-experimental two month storage period at 5 degrees C). Samples were instrumentally analysed every week for titratable acidity, soluble solid content, maturity index, and ethanol and acetaldehyde contents. In addition, four sensory attributes were assessed by 20 taste panellists (this work formed part of their training): acidity, maturity index, off-flavours and orange-like flavour. Principal components analysis was performed to determine the correlation structure of the sensorial data. This showed that the presence of off-flavours reduced the orange-like flavour perceived, but affected neither the acidity nor the maturity index. Acidity correlated negatively with the sensorially-perceived maturity index. The higher temperatures reduced the orange-like flavour and increased the presence of off-flavours over storage; this had a negative impact on the sensorial quality of the fruit. These effects were statistically significant, though more accurate results may have been obtained had the panellists received more training
Two native pupal parasitoids of Ceratitis capitata (Diptera, Tephritidae) found in Spain
Get PDFSearching native parasitoids of Ceratitis capitata is one of the activities carried out in the
Valencian Community in plots of citrus and other fruit trees. Adults of two different species of
hymenopterous insects have been obtained from medfly puparia reared under laboratory conditions.
The pteromalids Spalangia cameroni Perkins and Pachycrepoideus vindemmiae (Rondani) have been
identified as idiobiont pupal parasitoids of the Medfly
Identification of an Erwinia sp different from Erwinia amylovora and responsible for necrosis on pear blossoms
No full textNecrotic pear blossoms (NPB) were found in several pear orchards of ‘Ercolini’ (‘Coscia’) and ‘Tendral’ in Turís, Valencia (Spain), in April 1999, during a routine survey, in an area free of Erwinia amylovora. The symptoms resembled those of fire blight [E. amylovora] but affected only blossoms and did not progress to other parts of the tree. Erwinia-like colonies were isolated from the necrotic blossoms that year and the following 2 years, and the morphology of the colonies on CCT medium of Ishimaru and Klos, King’s B medium, and sucrose nutrient agar was similar to that of Erwinia amylovora. The isolates were identified as an Erwinia sp. by their microbiological characteristics and showed API 20E, API 20NE, API ZYM, API 50CH patterns and fatty acid profiles similar, but not identical, to those of E. amylovora and Erwinia pyrifoliae. The isolates reacted as E. amylovora in immunofluorescence with several antisera and one monoclonal antibody (MAb) employed for E. amylovora detection, but did not react in the enzyme-linked immunosorbent assay against specific E. amylovora monoclonal antibodies. Polymerase chain reaction with primers from 23S rDNA sequences of E. amylovora were positive, but no signal was obtained with primers from plasmid pEa29 or from chromosomal DNA sequences of E. amylovora. The isolates were able to elicit the hypersensitive reaction on tobacco and tomato leaves and to induce necrosis in pear flowers, but were unable to develop typical fire blight symptoms in other organs of pear trees, and on various host plants of E. amylovora. The isolated Erwinia sp. strains are pathogenic and different from E. amylovora and other described bacterial species affecting pear trees
Comportamiento productivo al aire libre y en invernadero de híbridos entre materiales locales de berenjena (Solanum melongena)
Get PDFLos híbridos de berenjena (Solanum melongena L.) son las variedades predominantes para
cultivo en invernadero en nuestro país (Prohens et al., 2005a). La selección y desarrollo de
híbridos para cultivo en invernadero ha permitido obtener materiales con una buena adaptación
a las estas condiciones. En cambio, en cultivo al aire libre ha existido un predominio de
las variedades no híbridas. Sin embargo, en los últimos años se está incrementando el uso de
híbridos al aire libre, utilizándose, fundamentalmente las mismas variedades que para cultivo
en invernadero (Marín, 2005). Ya que la berenjena es un cultivo que presenta vigor híbrido
para caracteres relacionados con la producción al cruzar parentales no relacionados (Prohens
et al., 2005b), la utilización de germoplasma local, adaptado a las condiciones de cultivo al
aire libre, podría contribuir al desarrollo de nuevos híbridos mejorados. Asimismo, es de interés
conocer el potencial de estos materiales para el desarrollo de nuevos híbridos para cultivo
en invernadero
Interactions Between Citrus Viroids Affect Symptom Expression and Field Performance of Clementine Trees Grafted on Trifoliate Orange
Get PDFCitrus exocortis viroid (CEVd), Citrus bent leaf viroid (CBLVd), a noncachexia variant of Hop stunt viroid (HSVd), Citrus viroid III (CVd-III), and Citrus viroid IV (CVd-IV) were co-inoculated as two-, three-, four-, and five-viroid mixtures to Clementine trees grafted on trifoliate orange to evaluate their effect on symptom expression, tree growth, and fruit yield. Most trees infected with CEVd-containing viroid mixtures developed exocortis scaling symptoms, as did CEVd alone, whereas most trees infected with HSVd- or CVd-IV-containing mixtures developed bark-cracking symptoms. Trees infected with mixtures containing both CEVd and CVd-IV revealed the existence of antagonism between these two viroids in terms of the expected bark-scaling and cracking symptoms. Synergistic interactions also were identified in trees infected with certain viroid combinations that, in spite of lacking CEVd, expressed exocortis-like scaling symptoms. Viroid interactions also affected the expected response of trees in terms of vegetative growth and fruit yield. Trees infected with viroid combinations containing CEVd or CVd-III were smaller and produced less fruit than trees infected with mixtures not containing these viroids. Viroid interactions on scion circumference and cumulative fruit yield, in terms of additivity of their effects, were statistically confirmed using a factorial analysis of variance model with two mean estimation approaches. In single-viroid infections, CEVd, CVd-III, and, to a lesser extent, CBLVd consistently and significantly reduced tree size and fruit yield. Conversely, HSVd and CVd-IV slightly increased fruit yield and reduced scion circumference. Rare and not consistent significant interactions were detected with the five-, four-, and three-viroid combinations. Antagonistic interactions between CEVd and CVd-III or CBLVd and CVd-III were revealed over the years with consistent significance. The antagonistic interaction between CEVd and CVd-IV was highly significant over the years when additional viroids were present; however, this antagonism appeared much later in the case of an exclusive interaction. HSVd and CVd-IV showed a consistent and significant synergistic interaction on yield only when both viroids were exclusively present. These results demonstrate antagonistic or synergistic relationships between citrus viroids depending on the viroid mixtures present in the host