ReDivia - Repositorio Digital de l'Instit Valencià d'Investigacions Agràries
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Suitability of the tomato borer Tuta absoluta as prey for Macrolophus pygmaeus and Nesidiocoris tenuis
No full textThe tomato borer, Tuta absoluta (Meyrick) (Lep.: Gelechiidae), is an important tomato pest native to South America, which appeared in eastern Spain at the end of 2006. Prey suitability of T. absoluta eggs and larval instars was examined under laboratory conditions to evaluate whether two indigenous predators, Macrolophus pygmaeus (Rambur) and Nesidiocoris tenuis Reuter (Hem.: Miridae), can adapt to this invasive pest. Both predators preyed actively on T. absoluta eggs and all larval stages, although they preferred first-instar larvae. Our results demonstrate that both mirids can adapt to this invasive pest, contributing to their value as biological control agents in tomato crops
Effect of recombinant gonadotropins on embryo quality in superovulated rabbit does and immune response after repeated treatments
No full textThis study aimed first to evaluate the effect of recombinant human FSH (rhFSH) with and without recombinant human LH (rhLH) on fresh and frozen-thawed embryo development and also to analyze the immune response of rabbit does (Oryctolagus cuniculus) subjected to repeated rhFSH treatments. Nulliparous New Zealand White does were used. In Experiment 1, 120 does were superovulated with 25 IU rhFSH alone or in combination with 5% or 10% rhLH (1.25 IU or 2.50 IU rhLH). A total of 1116 embryos at the compacted morula stage were cultured at 38.5 T, 5% CO(2), and saturated humidity for 48 It. The embryo development to hatching blastocyst was significantly lower for the group with 10% rhLH versus that of the control group (65.6 vs. 79.5 for rhFSH + 10% rhLH vs. control, respectively). However, no significant difference was found in development to hatching blastocyst for the control, rhFSH alone, and rhFSH + 5% rhLH groups. The developmental potential of frozen-thawed embryos obtained from all groups was similar, with an 83.5% in vitro development rate until the expanded blastocyst stage. To detect anti-FSH antibodies, in Experiment 2, does were subject to four superovulation treatments. The hormone administration had a significant effect on immune response in the superovulation group after two treatments (0.14 +/- 0.074 and 0.15 +/- 0.076 vs. 0.46 +/- 0.078 and 0.50 +/- 0.078 optical density for the first, second, third, and forth cycles, respectively). Nevertheless, none of the treated does had an immune response in both the first and second treatments; on the contrary, a significant increase in the antibody levels was observed in these females at the moment of the third and fourth superovulation treatments. In conclusion, rhFSH superovulation treatments increase the reproductive potential of rabbit does. (C) 2009 Elsevier Inc. All rights reserved
Effect of a Field-Source Mixture of Citrus Viroids on the Performance of Nules; Clementine and Navelina; Sweet Orange Trees Grafted on Carrizo Citrange
Get PDFA field-source mixture of citrus viroids was characterized and shown to contain Citrus exocortis viroid (CEVd), Hop stunt viroid (HSVd), Citrus bent leaf viroid (CBLVd), and Citrus dwarfing viroid (CDVd). Sequencing results showed that: (i) CEVd contained the PL and PR characteristic of class A variants; (ii) HSVd was a noncachexia variant; (iii) CBLVd was related to CVd-Ia variants; (iv) CDVd was a mixture of two types (CVd-IIIa and CVd-IIIb) of variants. The presence of the same type of variants in inoculated clementine (Citrus clementina ‘Nules’) and sweet orange (C. sinensis ‘Navelina’) trees on Carrizo citrange (Poncirus trifoliata × C. sinensis) rootstocks was confirmed. The effect of infection was determined by assessing the performance of infected and noninfected trees growing in the field. Infection resulted in small trees with reduced canopy, yielding a reduced crop. Fruit characteristics were also affected: (I) clementine and sweet orange fruits from infected trees were larger than those from noninfected trees; (II) clementine fruits from infected trees differed in shape from those of noninfected trees; (III) sweet orange fruits from infected trees had maturity indexes and juice contents higher than those from noninfected trees; (IV) in both species, the density of the juice, the amount of soluble solids, and the acidity of the fruits from infected trees were lower than those of fruits from noninfected trees. Infected trees had a poorly developed root system with fibrous roots containing fewer amyloplasts than noninfected trees. The results of an in vitro assay on the induction and development of roots in cultured explants are discussed
Non-additive phenotypic and transcriptomic inheritance in a citrus allotetraploid somatic hybrid between C. reticulata and C. limon: the case of pulp carotenoid biosynthesis pathway
No full textAllopolyploidy is known to induce novel patterns of gene expression and often gives rise to new phenotypes. Here we report on the first attempt to relate phenotypic inheritance in an allotetraploid somatic hybrid with gene expression. Carotenoid compounds in the fruit pulp of the two parental species and the hybrid were evaluated quantitatively by HPLC. Only very low levels of beta-carotene and beta-cryptoxanthin were observed in Citrus limon, while beta-cryptoxanthin was a major component of C. reticulata, which also displayed high levels of phytoene, phytofluene, beta-carotene, lutein, zeaxantin and violaxanthin. Total carotenoid content in mandarin juice sacs was 60 times greater than that in lemon. The allotetraploid hybrid produced all the same compounds as mandarin but at very low levels. Transgressive concentration of abscisic acid (ABA) was observed in the somatic hybrid. Real-time RT-PCR of total RNA from juice sacs was used to study expression of seven genes (CitDxs, CitPsy, CitPds, CitZds, CitLcy-b, CitChx-b, and CitZep) of the carotenoid biosynthetic pathway and two genes (CitNced1 and CitNced2) involved in abscisic acid synthesis from carotenoid. Gene expression was significantly higher for mandarin than lemon for seven of the nine genes analyzed. Lemon under expression was partially dominant in the somatic hybrid for three upstream steps of the biosynthetic pathway, particularly for CitDxs. Transgressive over expression was observed for the two CitNced genes. A limitation of the upstream steps of the pathway and a downstream higher consumption of carotenoids may explain the phenotype of the somatic hybrid
Rootstock Effects on Leaf Photosynthesis in 'Navelina' Trees Grown in Calcareous Soil
Get PDFCitrus crops in the Mediterranean region are often grown in high pH calcareous soils, which promote nutrient imbalances, especially iron deficiency. 'Navelina' trees grafted on eight different citrus rootstocks were assessed in terms of their relative tolerance to these soils. To do so, leaf gas exchange and chlorophyll a fluorescence parameters were measured for 2 consecutive years in leaves without visible injury symptoms. Trees were grown on the rootstocks Carrizo citrange, hybrids of Cleopatra mandarin x Poncirus trifoliata no. 5 (F-A 5),13 (F-A 13), and 16 (030116), Troyer citrange x common mandarin no. 18 (F-A 418), King mandarin x P. trifoliata no. 7 (F-A 517), 020324 (Troyer citrange x Cleopatra mandarin), and Volkamer lemon x P. trifoliata no. 64 (230164). gs and transpiration rate were clearly lower in leaves of shoots grafted on Carrizo citrange than in those on the other rootstocks assayed, but net photosynthetic flux did not differ. However, leaves of shoots on Carrizo citrange displayed a decline in their maximum quantum yield of PSII photochemistry [variable fluorescence/maximum fluorescence (F(v)/F(m)) ratio] and other chlorophyll parameters in the steady state such as photochemical quenching (qp) and the quantum efficiency of PSII photochemistry as well as an increase in nonphotochemical quenching (q(N)). Other rootstocks such as 030116, F-A 517 and, especially, F-A 5 showed the highest Phi(PSU) and F(v)/F(m) values, whereas F-A 5 had the lowest qN in the steady state. The photosynthetic characteristics observed in leaves on Carrizo citrange showed them to be the least tolerant to these calcareous conditions, whereas photosynthesis of 'Navelina' trees budded on F-A 5 were the most tolerant
Simple and Rapid Method for PCR Characterization of Large Bacillus thuringiensis Strain Collections
No full textPolymerase chain reaction (PCR)-based identification of Bacillus thuringiensis toxin genes has become a routine step in most B. thuringiensis isolation and characterization initiatives. In the present study we propose a simplified method for extensive PCR analysis of B. thuringiensis cry and cyt genes of particular interest in large-scale screening programs. Fifty B. thuringiensis strains were screened for the presence of genes of the cry1 subfamily. Identical results were obtained when our method was used in comparison to other methodology based on a standard alkaline lysis preparation of plasmid DNA. Additional tests evidenced the fitness of our method in a particular multiplex-PCR analysis. The main advantages of the proposed methodology are that it is simpler and quicker than commonly used protocols (as DNA template preparation is substituted by direct addition of small amounts of B. thuringiensis liquid cell suspension to the reaction mixture) and that it allows simultaneous handling (bacterial growth and PCR) of up to 96 strains per round
Headspace-based techniques to identify the principal volatile compounds in red grape cultivars
No full textThe control of the raw material has a great influence on the final quality of wine. Nowadays, wineries have practically not incorporated an effective quality control of grape juice on their production process. Although wine aroma has been widely analysed, grape juice aroma for wine-making has been poorly studied. In this study, two headspace-based technique methodologies have been proposed to characterise the aroma of grape juice: static headspace (SHS) and headspace solid phase microextraction (HS-SPME). Both techniques were applied on the samples from three maturation stages of two red grape cultivars: Tempranillo and Bobal, ranked first in Spanish and in Valencian Community cultivars, respectively. This study identifies the principal volatile compounds of grape juice: C(6) compounds, especially alcohols and aldehydes, using both techniques. It was confirmed that SHS and HS-SPME techniques could be incorporated into the process of the grape quality control in wineries as a result of its operational simplicity, low cost and reduced ecological impact compared with other conventional organic solvent-based techniques
Delay of early fruitlet abscission by branch girdling in citrus coincides with previous increases in carbohydrate and gibberellin concentrations
No full textCurrent evidence in citrus indicates that gibberellins (GAs) are main determinants of early fruit set while subsequent growth of developing fruits is mostly dependent upon carbohydrate availability. In this work, branch girdling performed at anthesis in Satsuma mandarin (Citrus unshiu (Mak.) Marc.) cv. Okitsu transitorily reduced early abscission rates (12-32 days after anthesis, DAA) delaying initially the process of natural fruitlet drop. The effects of girdling on growth, gibberellin (GA) and carbohydrate concentrations in developing ovaries and fruitlets were assessed during this initial growth stage (0-69 DAA). In girdled branches, abscission rate reduction was preceded by elevated concentrations of carbohydrate and GA in developing ovaries and fruitlets. Girdling at anthesis stimulated higher hexose (21 DAA) and starch (6-20 DAA) concentrations and also higher GA(1) (6 DAA), GA(19) (13-20 DAA) and GA(20) (6-20 DAA). The results established a relationship between the reduction of early abscission rates and higher concentrations of carbohydrates and GAs induced by girdling in developing fruitlets. These findings revealed that girdling certainly increased GA concentration and strongly suggested that its effect on early fruitlet abscission delay is likely mediated by both GA and carbohydrates
A novel hybridization approach for detection of citrus viroids
No full textCitrus plants are natural hosts of several viroid species all belonging to the family Pospiviroidae. Previous attempts to detect viroids from field-grown species and cultivars yielded erratic results unless analyses were performed using Etrog citron a secondary bio-amplification host. To overcome the use of Etrog citron a number of RT-PCR approaches have been proposed with different degrees of success. Here we report the suitability of an easy to handle northern hybridization protocol for viroid detection of samples collected from field-grown citrus species and cultivars. The protocol involves: (i) Nucleic acid preparations from bark tissue samples collected from field-grown trees regardless of the growing season and storage conditions; (ii) Separation in 5% PAGE or 1% agarose, blotting to membrane and. xing; (iii) Hybridization with viroid-specific DIG-labelled probes and detection with anti-DIG-alkaline phosphatase conjugate and autoradiography with the CSPD substrate. The method has been tested with viroid-infected trees of sweet orange, lemon, mandarin, grapefruit, sour orange, Swingle citrumello, Tahiti lime and Mexican lime. This novel hybridization approach is extremely sensitive, easy to handle and shortens the time needed for reliable viroid indexing tests. The suitability of PCR generated DIG-labelled probes and the sensitivity achieved when the samples are separated and blotted from non-denaturing gels are discussed
Acta Horticulturae
No full textConventional breeding of fruit trees is a slow process due to their long generation time as well as high degree of heterozygosis of these species. Biotechnology techniques and in vitro tissue culture, which includes genetic transformation, are considered promising for the improvement of these species. An efficient protocol for regeneration of whole plants is a prerequisite for the development of an efficient Agrobacterium-mediated transformation system. The objective of this paper was to develop a protocol for plant regeneration of Diospyros kaki Thunb. cv. ‘Rojo Brillante’ via organogenesis from leaf explants. Combined phytohormones and dosage were evaluated for regeneration. The best regeneration efficiencies (29.2%) were obtained with 9 mg/L zeatin in combination with 0.1 mg/L naphtalenacetic acid. The cultures were maintained in the dark for 20 days followed by incubation under photoperiod conditions. Shoots were micrografted in vitro onto seedling rootstocks. The rootstocks came from Diospyros virginiana L. seedlings; they were micrografted after 6 to 8 days after germination