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Detrimental effect on availability of buserelin acetate administered in seminal doses in rabbits
No full textThe study evaluated a seminal effect on the ability to induce ovulation of a synthetic GnRH analogue, buserelin acetate, administered by vaginal mucosa in rabbit does. In a first experiment, 751 receptive nulliparous and multiparous non-lactating does were randomly assigned to groups of different seminal doses (6, 12, 24, 50, and 100 million total sperm in 0.5 mL). All seminal doses contained 5 mu g of buserelin acetate to induce ovulation by vaginal mucosa absorption. Two hundred and six does from 751 were laparoscopized at 12(th) days of gestation to evaluate ovulation induction, ovulation rate and implanted embryos, while pregnancy rate and total and live born were noted in all females. Results showed that the pregnancy rate was significantly affected by the seminal dose used (0.82 vs 0.72, 0.50, and 0.45, for 6, 24, 50, and 100 million of spermatozoa, respectively). Data from laparoscopized does showed significant differences between the group of 6 and 50 million sperm dose in the ovulation induction and consequently in the pregnancy rate (0.79 vs 0.52, 0.79 vs 0.48, respectively). Does from all groups had similar implanted embryos and litter sizes irrespective of seminal dose used. In a second experiment, inseminations were done without spermatozoa, 0.5 mL of two dilutions of seminal plasma (1/4 and 1/20) with 5 mu g of buserelin acetate were introduced into vagina from 71 receptive females and its results were compared to a control group (35 does) induced to ovulate with 1 mu g of buserelin acetate administered intramuscularly. Only 40% of females from 1/4 plasma dilution group became to ovulate. Consequently, the dilution rate of seminal plasma may reduce the availability rate of the GnRH analogue and the concentration needed to provoke the ovulation induction. (C) 2011 Elsevier Inc. All rights reserved
Multilocus half-tetrad analysis and centromere mapping in citrus: evidence of SDR mechanism for 2n megagametophyte production and partial chiasma interference in mandarin cv 'Fortune'
No full textThe genetic structure of 2n gametes and, particularly, the parental heterozygosity restitution at each locus depends on the meiotic process by which they originated, with first-division restitution and second-division restitution (SDR) being the two major mechanisms. The origin of 2n gametes in citrus is still controversial, although sexual polyploidisation is widely used for triploid seedless cultivar development. In this study, we report the analysis of 2n gametes of mandarin cv 'Fortune' by genotyping 171 triploid hybrids with 35 simple sequence repeat markers. The microsatellite DNA allele counting-peak ratios method for allele-dosage evaluation proved highly efficient in segregating triploid progenies and allowed half-tetrad analysis (HTA) by inferring the 2n gamete allelic configuration. All 2n gametes arose from the female genitor. The observed maternal heterozygosity restitution varied between 10 and 82%, depending on the locus, thus SDR appears to be the mechanism underlying 2n gamete production in mandarin cv 'Fortune'. A new method to locate the centromere, based on the best fit between observed heterozygosity restitution within a linkage group and theoretical functions under either partial or no chiasmata interference hypotheses was successfully applied to linkage group II. The maximum value of heterozygosity restitution and the pattern of restitution along this linkage group would suggest there is partial chiasma interference. The implications of such a restitution mechanism for citrus breeding are discussed. Heredity (2011) 107, 462-470; doi:10.1038/hdy.2011.33; published online 18 May 201
Acta Horticulturae
No full textDifferent deficit irrigation strategies were carried out during seven consecutive years in a young Japanese plum drip irrigated orchard in Spain. The long-term effects of these treatments are summarized. By the end of the seventh year, the water restrictions did not lead to any soil salt accumulation in the dripper zone, a concern when deficit irrigation is applied in the long-term. However, the water restriction led to smaller trees (28% in canopy shaded area). This had a carry over effect on yield which was reduced by 18% in the eighth season, when trees were fully watered, compared to the control. After the seven years of deficit irrigation, several watering and crop load regimes were employed in order to accelerate the recovery of the vegetative growth. The more successful strategy was increasing the wetting zone by adding drippers with water application up to 133% of crop evapotranspiration. This was particularly effective when carried out together with lowering the crop load in order to alleviate the vegetative versus fruit growth competition. After two years of applying this strategy, the previously deficit irrigated trees were able to obtain a similar tree size than the control trees. The results provide for some insights on how to manage the watering regime when a scenario of full water availability follows a drought cycle
Somatic hybridization for citrus rootstock breeding: an effective tool to solve some important issues of the Mediterranean citrus industry
No full textThe prevalence of sour orange rootstock in the southern and eastern part of the Mediterranean Basin is presently threatened by the spread of Citrus Tristeza Virus (CTV) and its main vector Toxoptera citricida, combined with abiotic constraints such as drought, salinity and alkalinity. The search for alternative CTV-resistant rootstocks that also withstand the other constraints is now considered an urgent priority for a sustainable citrus industry in the area. Complementary progenitors can be found in citrus germplasm to combine the desired traits, particularly between Poncirus and Citrus genera. The production of somatic hybrids allows cumulating all dominant traits irrespective of their heterozygosity level, and would appear to be an effective way to solve the rootstock challenge facing the Mediterranean citrus industry. This paper presents the results obtained during a regional collaborative effort between five countries, to develop new rootstocks by somatic hybridization. New embryogenic callus lines to be used for somatic hybridization have been created. Protoplast fusions have been performed at CIRAD and IVIA laboratories, focusing on intergeneric combinations. Analysis of ploidy level by flow cytometry and molecular markers confirmed the acquisition of new interesting tetraploid somatic hybrids for six combinations. Diploid cybrids with intergeneric (Citrus x Poncirus) nucleus and C. reticulata or C. aurantifolia mitochondria were also identified for four combinations. The agronomical performance of a pre-existing somatic hybrid between Poncirus trifoliata and Citrus reticulata was validated in calcareous soils in Morocco. Somatic hybridization is now integrated into the breeding programs of the five Mediterranean countries
Detection, discrimination and absolute quantitation of Tomato spotted wilt virus isolates using real time RT-PCR with TaqMan (R) MGB probes
No full textA quantitative real-time reverse transcription-polymerase chain reaction (RT-qPCR) procedure using a general primer set and three TaqMan (R) MGB probes was developed for general and genotype-specific detection and quantitation of the genomic M segment of Tomato spotted wilt virus (TSWV). Standard curves using RNA transcripts homologous to the three probes allowed reproducible quantitative assays with a wide dynamic range (10(3)-10(10) TSWV M segment RNA copies/ng of total RNA) and high sensitivity. This protocol was assayed with a battery of TSWV isolates, covering the range of the present known genetic variation, in single and/or mix infections in three plant hosts, as well as in the thrips vector Frankliniella occidenialis. This quantitative detection assay will be a valuable tool for molecular biology and epidemiology studies, diagnosis and disease control
Ectopic expression of the p23 silencing suppressor of Citrus tristeza virus differentially modifies viral accumulation and tropism in two transgenic woody hosts
Get PDFCitrus tristeza virus (CTV), a phloem-restricted closterovirus infecting citrus, encodes three different silencing suppressors (p25, p20 and p23), one of which (p23) is a pathogenicity determinant that induces aberrations resembling CTV symptoms when expressed ectopically in transgenic citrus hosts. In this article, the effect of p23 ectopic expression on virus infection was examined in sweet orange (SwO), a highly susceptible host, and sour orange (SO), which severely restricts CTV cell-to-cell movement. Transgenic plants of both species ectopically expressing p23, or transformed with an empty vector, were graft inoculated with the mild CTV isolate T385 or with CTV-BC1/GFP, a clonal strain derived from the severe isolate T36 carrying the gene for the green fluorescent protein (GFP). CTV distribution in infected tissues was assessed by direct tissue blot immunoassay and fluorescence emission, and virus accumulation was estimated by quantitative real-time reverse transcriptase-polymerase chain reaction. CTV accumulation in p23-expressing and control SwO plants was similar, whereas the viral load in transgenic SO expressing p23 was 10-10(5) times higher than in the cognate control plants. Although few infection foci composed of a single cell were observed in the phloem of CTV-infected control SO, the number of foci in p23-expressing plants was higher and usually comprised two to six cells, indicating viral cell-to-cell movement. CTV was detected in mesophyll protoplasts and cells from infected SO and SwO expressing p23, but not in similar protoplasts and cells from infected control plants. Our results show that the ectopic expression of p23 enables CTV to escape from the phloem and, in addition, facilitates systemic infection of the resistant SO host. This is the first report of a viral-encoded protein that enhances virus accumulation and distribution in woody hosts
Usefulness of trunk diameter variations as continuous water stress indicators of pomegranate (Punica granatum) trees
No full textPomegranate trees (Punica granatum L.) is a deciduous fruit tree included in the so-called group of minor fruit tree species, not widely grown but of some importance in the south east of Spain. Pomegranate trees are considered as a culture tolerant to soil water deficit. However, very little is known about pomegranate orchard water management. The objective of this research was to asses the feasibility of using trunk diameter variation (TDV) indexes, obtained by means of LVDT sensors, as a plant water stress indicators for pomegranate trees. The experiment was carried out with mature trees grown in the field under three irrigation regimes: control well watered trees; trees continuously deficit irrigated at 50% of the control regime (SDI); and trees that had a summer water stress cycle being irrigated at 25% of the control rates only in July and August (RDI). The seasonal variations of maximum diurnal trunk shrinkage (MDS) and trunk growth rates (TGR) were compared with midday stem water potential (Psi stem) measurements. During the course of the entire season, control trees maintained lower MDS values than the SDI ones. In the RDI treatment, as water restrictions began, there was a slow increase in MDS, in correspondence with a decrease in Psi stem. When water was returned at full dosage, the RDI quickly recovered to MDS and Psi stem values similar to the control. However, lower MDS for a given Psi stem values were observed as the season advanced. The magnitude of differences between well watered and deficit irrigated trees was much larger in the case of MDS than for tPstem. However, the tree-to-tree variability of the MDS readings was more than four times higher than for Psi stem; average coefficient of variation of 7.5 and 36% for Psi stem and MDS, respectively. On the other hand, TGR did not clearly reflect differences in tree water status. Overall, results reported indicated that MDS is a good indicator of pomegranate tree water status and it can be further used for managing irrigation. However, the seasonal changes in the MDS-Psi stem relationship should be taken into account when attempting to use threshold MDS values for scheduling irrigation. (C) 2011 Elsevier B.V. All rights reserved
The Gypsy Database (GyDB) of mobile genetic elements: release 2.0
Get PDFThis article introduces the second release of the Gypsy Database of Mobile Genetic Elements (GyDB 2.0): a research project devoted to the evolutionary dynamics of viruses and transposable elements based on their phylogenetic classification (per lineage and protein domain). The Gypsy Database (GyDB) is a long-term project that is continuously progressing, and that owing to the high molecular diversity of mobile elements requires to be completed in several stages. GyDB 2.0 has been powered with a wiki to allow other researchers participate in the project. The current database stage and scope are long terminal repeats (LTR) retroelements and relatives. GyDB 2.0 is an update based on the analysis of Ty3/Gypsy, Retroviridae, Ty1/Copia and Bel/Pao LTR retroelements and the Caulimoviridae pararetroviruses of plants. Among other features, in terms of the aforementioned topics, this update adds: (i) a variety of descriptions and reviews distributed in multiple web pages; (ii) protein-based phylogenies, where phylogenetic levels are assigned to distinct classified elements; (iii) a collection of multiple alignments, lineage-specific hidden Markov models and consensus sequences, called GyDB collection; (iv) updated RefSeq databases and BLAST and HMM servers to facilitate sequence characterization of new LTR retroelement and caulimovirus queries; and (v) a bibliographic server. GyDB 2.0 is available at http://gydb.org
Marinomonas alcarazii sp nov., M. rhizomae sp nov., M. foliarum sp nov., M. posidonica sp nov and M. aquiplantarum sp nov., isolated from the microbiota of the seagrass Posidonia oceanica
No full textFive novel Gram-reaction-negative aerobic marine bacterial strains with DNA G+C contents <50 mol% were isolated from the seagrass Posidonia oceanica. 16S rRNA sequence analysis indicated that they belonged to the genus Marinomonas. Major fatty acid compositions, comprising C(10:0) 3-OH, C(16:0), C(16:1)omega 7C and C(18:1)omega 7c, supported the affiliation of these strains to the genus Marinomonas. Strains IVIA-Po-14b(T), IVIA-Po-145(T) and IVIA-Po-155(T) were closely related to Marinomonas pontica 46-16(T), according to phylogenetic analysis. However, DNA-DNA hybridization values <35% among these strains revealed that they represented different species. Further differences in the phenotypes and minor fatty acid compositions were also found among the strains. Another two strains, designated IVIA-Po-181(T) and IVIA-Po-159(T), were found to be closely related to M. dokdonensis DSW10-10(T) but DNA-DNA relatedness levels <40% in pairwise comparisons, as well as some additional differences in phenotypes and fatty acid compositions supported the creation of two novel species. Accordingly, strains IVIA-Po-14b(T) (=CECT 7730(T) =NCIMB 14671(T)), IVIA-Po-145(T) (=CECT 7377(T) =NCIMB 14431(T)), IVIA-Po-155(T) (=CECT 7731(T) =NCIMB 14672(T)), IVIA-Po-181(T) (=CECT 7376(T) =NCIMB 14433(T)) and IVIA-Po-159(T) (=CECT 7732(T) =NCIMB 14673(T)) represent novel species, for which the names Marinomonas alcarazii sp. nov., Marinomonas rhizomae sp. nov., Marinomonas foliarum sp. nov., Marinomonas posidonica sp. nov. and Marinomonas aquiplantarum sp. nov. are proposed, respectively
'Moixent', an Apricot Resistant to Sharka
Get PDF‘Moixent’ is a self-compatible, earlyripening apricot cultivar (Prunus armeniaca L.) with excellent fruit quality and resistance to sharka (plum pox virus), a serious disease limiting apricot fruit production in affected areas. ‘Moixent’ fruits have excellent organoleptic characteristics, significantly improved
from other early cultivars available in themarket.
‘Moixent’ is well adapted to areas with warm winter and Mediterranean climate and presents good fruit set and productivity