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Optimizing conditions for treating goat semen with cholesterol-loaded cyclodextrins prior to freezing to improve cryosurvival
No full textThe fertility of goat sperm is highly variable and new methods for improving sperm cryosurvival are needed. Cholesterol plays important roles in membrane fluidity, cold shock sensitivity and cryodamage, and treating sperm from cold-shock sensitive species with cholesterol-loaded cyclodextrins (CLC) prior to cryopreservation enhances sperm cryosurvival. The aim of this study was to develop a CLC-treatment to optimize goat sperm cryopreservation. A total of 45 ejaculates coming from eleven adult Murciano-Granadina bucks were used and three experiments were conducted to determine: (1) the optimal CLC concentration to treat goat sperm; (2) the optimal time to treat the sperm (before or after seminal plasma removal); and (3) optimal freezing diluent (either of two Tris-citrate diluents containing 2% or 20% egg yolk and 4% glycerol or a skim milk diluent with 7% glycerol) to cryopreserve goat sperm. Goat sperm cryosurvival rates were greatest when they were treated with 1 mg CLC/120 x 10(6) sperm prior to freezing. The benefit was also greatest if the sperm were treated with CLC after seminal plasma removal. Finally, CLC treatment improved sperm cryosurvival rates for sperm frozen in all three diluents, however, CLC treatment was most effective for sperm frozen in egg-yolk diluents. In conclusion, treating goat sperm, with CLC prior to cryopreservation, improved sperm cryosurvival rates. In addition, CLC treatment was effective for all freezing diluents tested, making this technology practical for the industry using current cryopreservation techniques. Nevertheless, additional studies should be conducted to determine how CLC might affect sperm functionality and fertilizing ability
Effect of sustained and regulated deficit irrigation on fruit quality of pomegranate cv. 'Mollar de Elche' at harvest and during cold storage
No full textThe effect of several irrigation strategies on fruit quality at harvest and during cold storage at 5 °C of ‘Mollar de Elche’ pomegranates (Punica granatum L.) was studied for three seasons. Irrigation treatments consisted of a control irrigated at 100% of crop evapotranspiration (ETc), a sustained deficit irrigation (SDI) where trees were irrigated at 50% of the ETc during the entire season, and three regulated deficit irrigation (RDI) treatments. In the RDI regimes, severe water restrictions (25% ETc) were applied during one of three phases: flowering and fruit set (RDIfl.-fr.set), fruit growth (RDIfr.gr) or the final phase of fruit growth and ripening (RDIripe). Results showed that after 8 or 19 weeks at 5 °C plus 7 days of shelf life at 20 °C, some fruit quality attributes such as the soluble solids content (SSC), anthocyanins and fruit colour were enhanced by deficit irrigation. Higher SSC and more reddish colouration in the fruit peel were noted at harvest and during cold storage in pomegranates from SDI and RDIripe. On the other hand, higher juice anthocyanins content were obtained in the RDIfr.gr. fruit. Control fruit showed greater susceptibility to physiological disorders manifested as peel pitting, blemishes and sinking, and to weight loss with respect to deficit irrigation samples. Weight loss increased with storage time and SDI and RDIripe showed lower weight loss compared to the control treatment. Deficit irrigation, depending on the phenological period when water shortage is applied, can be then used as a field practice to control fruit ripening timing, enhance pomegranate fruit composition and improve fruit postharvest performance
Centenario del Departamento del Arroz (1913-2013). Jornada Técnica Internacional sobre Investigación en Arroz. Sueca (Valencia), 7 y 8 de Febrero de 2013
No full textEn una parcela de arroz, situada en la localidad de Llaurí (Valencia), en el
entorno del Parque Natural de la Albufera, se realizó un ensayo sobre el aprovechamiento de
la paja de arroz, durante el periodo desde el 2003 hasta el 2010. Las modalidades de manejo
de la paja comparadas en el ensayo fueron: a) quema después de la recolección, b)
incorporación directa al suelo en las labores de finales del invierno preparatorias del cultivo,
y e) recogida. El diseño estadístico seguido ha sido el de bloques al azar con 3 repeticiones
de cada uno de los tratamientos comparativos, utilizando parcelas elementales de unos 400
m”. En todas las unidades experimentales se aplicaron las mismas técnicas de cultivo:
laboreo, fertilización, herbicidas, control fitosanitario, etc., las usuales del cultivo del arroz
en la zona.
Los resultados de producción de arroz durante las ocho campañas que ha durado el ensayo,
únicamente mostraron significación estadística en el primer año, registrándose el valor más
bajo con la incorporación de la paja. Pero las cifras de rendimiento medio de todas las
campañas han sido bastante similares: 8,69, 8,45 y 8,43 t/ha, con los tratamientos de quema,
incorporación y recogida de la paja, respectivamente, no presentado diferencias
significativas a nivel estadístico. Los resultados de producción de paja tampoco han dado
diferencias significativas entre los tres tipos de gestión de la paja. Asimismo el efecto del
manejo de la paja de arroz tuvo una escasa repercusión en los contenidos de nutrientes
esenciales en los órganos de las plantas de arroz, tanto en el grano como en la paja. Y en
cuanto a la calidad del suelo, se ha constatado que ninguno de los parámetros fundamentales
del suelo (químicos, físico-químicos y biológicos) ha resultado modificado de forma
significativa por la modalidad de gestión de la paja generada en la cosecha del arroz.
Estos resultados indican que los suelos de arrozal de la Comunidad Valenciana debido a su
alto poder amortiguador (textura arcillo-limosa, y niveles altos de materia orgánica),
precisan de un periodo muy largo de tiempo para que la incorporación de la paja al suelo
genere modificaciones significativas en las propiedades básicas del suelo
Acta Horticulturae
No full textIn Spain the persimmon production is based on the cultivar 'Rojo Brillante' which is astringent at harvest (PVA type). The application of postharvest CO2-treatments that allow removing the astringency while preserving the firmness has been the main factor for the important expansion of persimmon crop in the last decades. Relying the crop only on one cultivar implied agronomic and commercial risks, thus the availability of new cultivars is currently an important research goal. In this sense the Instituto Valenciano de Investigaciones Agrarias (IVIA, Spain) has recently started a program focused on the introduction of cultivars from other persimmon growth countries, with positive agronomic features as well as diversity in ripening date, astringency, and fruit characteristics. The study of the postharvest quality of those cultivars with good agronomic performance is necessary for their commercial potential. In this study the fruit quality at harvest of eight cultivars has been evaluated at two commercial maturity stages; diameter, firmness, external color, total soluble solids and level of astringency were determined. In those cultivars astringent at harvest, the effectiveness of deastringency treatment with high concentration of CO2, applied in commercial standard conditions, has also been investigated. The analysis of soluble tannins, acetaldehyde production and sensory astringency evaluation revealed that, although this treatment was effective in most of the cultivars assayed, some of them maintained a level of astringency too high after treatment for consumption. Moreover, maturity at harvest influences the effectiveness of the deastringency treatment on some cultivars
Phage dUTPases Control Transfer of Virulence Genes by a Proto-Oncogenic G Protein-like Mechanism
No full textdUTPases (Duts) have emerged as promising regulatory molecules controlling relevant cellular processes. However, the mechanism underlying this regulatory function remains enigmatic. Using staphylococcal pathogenicity island (SaPI) repression as a model, we report here that phage Duts induce the transfer of SaPI-encoded virulence factors by switching between active (dUTP-bound) and inactive (apo state) conformations, a conversion catalyzed by their intrinsic dUTPase activity. Crystallographic and mutagenic analyses demonstrate that binding to dUTP reorders the C-terminal motif V of the phage-encoded Duts, rendering these proteins into the active conformation required for SaPI derepression. By contrast, the conversion to the apo state conformation by hydrolysis of the bound dUTP generates a protein that is unable to induce the SaPI cycle. Because none of the requirements involving Duts in SaPI transfer are exclusive to the phage-encoded proteins, we propose that Duts are widespread cellular regulators acting in a manner analogous to the eukaryotic G proteins
Estudio de la flora arvense como posible reservorio natural de agentes implicados en el nuevo problema fitosanitario que afecta a los cultivos de apio y zanahoria en Villena (Alicante)
Get PDFResumen: En primavera de 2008 apareció una nueva patología en cultivos de apio (Apium graveolens) y zanahoria (Daucus carota) de la empresa Agrícola Villena Coop. V de Villena (Alicante). que provocó importantes pérdidas en ambos cultivos. Con el fin de identificar posibles reservorios naturales de los agentes implicados en su desarrollo, se tomaron muestras de las especias arvenses presentes en campos de apio y zanahoria y sus alrededores y se realizaron análisis moleculares para la detección de fitoplasmas, Spiroplasma citri y “Candidatus Liberibacter solanacearum”. Se procesaron 135 muestras de flora arvense, algunas presentaban alteraciones en su desarrollo, pero la gran mayoría eran asintomáticas. Se identificaron 58 especies pertenecientes a 23 familias. De los tres agentes fitopatógenos analizados, únicamente se detectaron fitoplasmas en Setaria adhaerens y Amaranthus blitoides
Use of chlorophyll fluorescence imaging as diagnostic technique to predict compatibility in melon graft
No full textGrafts cause stress in plants that can be measured by changes in chlorophyll (Chl) fluorescence. Variations in fluorescence parameters can be visualized through images that reveal spatial and temporal changes in grafted plants. To validate the sensitivity of chlorophyll fluorescence imaging (CFI) as a diagnostic method of studying compatibility/incompatibility in grafted plants, we used melon cultivars (‘Ricura’ and ‘Sancho’, Cucumis melo L. var. saccharinus Naud.) grafted onto Cucurbita maxima Duchesne × Cucurbita moschata Duchesne (‘Shintoza’). Previous results had shown different compatibility behaviour of the two cultivars, ‘Ricura’ (R) having in more relative frequency higher compatibility problems with ‘Shintoza’ (SH) rootstock than ‘Sancho’ (S). The use of double grafting using an intermediate melon cultivar between R and SH has proved effective in increasing compatibility. Among all the fluorescence parameters measured (Fv/Fm, ϕPSII and ϕNPQ), the Fv/Fm ratio, proportional to the maximal quantum yield of PSII photochemistry, was shown to be the most sensitive to graft stress.
The values of the Fv/Fm ratio images were higher in S single-grafted plants than R single grafted, while Fv/Fm values were similar in both cultivars in double grafted plants. On the other hand, R double grafted had higher Fv/Fm values than R single grafts.
The results showed that CFI is useful in evaluating graft compatibility problem
Identification of transcription factors potentially involved in the juvenile to adult phase transition in Citrus
No full textThe juvenile to adult transition (JAT) in higher plants is required for them to reach reproductive competence. However, it is a poorly understood process in woody plants, where only a few genes have been definitely identified as being involved in this transition. This work aims at increasing our understanding of the mechanisms regulating the JAT in citrus. Juvenile and adult plants from Pineapple sweet orange (Citrus sinensis) and Rough lemon (C. jambhiri) were used to screen for differentially expressed transcription factors (TFs) using a 115K microarray developed on the basis of the CitrusTF database. Murcott tangor (C. reticulata C. sinensis) and Duncan grapefruit (C. paradisi) were incorporated into the quantitative real-time reverse transcriptionPCR validation in order to select those genes whose phase-specific regulation was common to the four species. A browsable web database has been created with information about the structural and functional annotation related to 1152 unigenes of putative citrus TFs (CTFs). This database constitutes a valuable resource for research on transcriptional regulation and comparative genomics. Moreover, a microarray has been developed and used that contains these putative CTFs, in order to identify eight genes that showed differential expression in juvenile and adult meristems of four different species of citrus. Those genes have been characterized, and their expression pattern in vegetative and reproductive tissues has been analysed. Four of them are MADS-box genes, a family of TFs involved in developmental processes, whereas another one resembles MADS-box genes but lacks the MADS box itself. The other three showed high partial sequence similarity restricted to specific Arabidopsis protein domains but negligible outside those domains. The work presented here indicates that the JAT in citrus could be controlled by mechanisms that are in part common to those of Arabidopsis, but also somehow different, since specific factors without Arabidopsis orthologues have also been characterized. The potential involvement of the genes in the JAT is discussed
Elucidating mechanisms underlying organ abscission
No full textAbscission consists in the detachment of entire vegetative and reproductive organs due to cell separation processes occurring at the abscission zones (AZs) at specific positions of the plant body. From an evolutionary point of view, abscission is a highly advantageous process resulting into fruit and seed dispersal as well as the shedding of no longer useful organs. In an agricultural context, however, abscission may become a major limiting factor for crop productivity. Domestication of major crops included the selection of plants that did not naturally shed ripe fruits or seeds. The understanding of abscission is of great importance to control seed and fruit production and to improve breeding and harvesting practices. Thus, advances made on model plants and crops are of major importance since they may provide potential candidate genes for further biotechnological applications. Here, we review the current knowledge of the physiological, genetic and genomic aspects related to abscission including the most recently disclosed putative regulators that appear to be implicated in the development and/or activation of the AZs. (C) 2012 Elsevier Ireland Ltd. All rights reserved
Cucumber vein yellowing virus isolate-specific expression of symptoms and viral RNA accumulation in susceptible and resistant cucumber cultivars
No full textSince its outbreak in Spain during the fall of 2000, Cucumber vein yellowing virus (CVYV) has become into a limiting factor in cucurbit cultivation in this country, particularly in cucumber. The impact of the virus has been limited after the introduction of resistant cucumber cultivars and the implementation of cultural practices to control whitefly, the virus vector. In Spain, CVYV isolates are genetically similar and cucumber resistance breaking isolates have not been reported. A CVYV isolate from Jordan (Jor) was previously reported as being more virulent in cucumber cv. Beit Alfa than an isolate from Israel. To study the reactions of different cucumber cultivars to the virulent Jor isolate in comparison with a Spanish isolate of (Alm 1A), we have inoculated both isolates in 10 commercial cucumber cultivars with resistance to the virus. Also, we have used real-time RT-PCR to estimate virus accumulation of Jor and Alm 1A isolates in three of these cultivars, one described as susceptible and two as resistant to CVYV. The Spanish Alm 1A isolate caused mild or no symptoms in resistant cultivars whereas Jor isolate caused intense symptoms in all cultivars. Alm 1A genomic RNA accumulated similarly in the three cultivars, whereas the accumulation of Jor genomic RNA was lower in the resistant cultivars than in the susceptible cultivar. Also the Jor isolate and accumulated earlier and at a higher level than the Alm 1A isolate in the three cultivars. (C) 2012 Elsevier Ltd. All rights reserved