Sanitation of olive plants infected by Verticillium dahliae using heat treatments

Verticillium wilt, caused by the fungus Verticillium dahliae, is currently the most important disease affecting olive in the Mediterranean basin. There are no effective treatments for controlling this disease. The use of infected nursery stocks has largely contributed to the spread of the pathogen, and therefore the development of treatments to preventively sanitize the propagation stock is critical in the nursery industry. This study describes novel techniques to achieve this aim. The effects of several temperature–exposure time combinations were evaluated: (i) the survival of pathogen on culture medium (PDA); (ii) the pathogen viability on infected shoots and plants; (iii) the vegetative growth of plants of several cultivars; and (iv) the rooting ability of cuttings. The colonies of the pathogen growing in PDA were killed after 8 h and 60 min of exposure at 40 and 47°C, respectively. Temperatures ≥42°C for at least 2 h were lethal for the pathogen infecting the shoots. Likewise, moist hot air treatments at 42–44°C for 6–12 h eradicated the pathogen, without compromising the viability of the plants. Five olive cultivars were also evaluated and classified according to their thermotolerance as follows: sensitive (Chiquitita), moderately sensitive (Koroneiki, Frantoio and Picual) and heat tolerant (Arbequina). However, the optimized sanitation methods were applicable to all of the cultivars. Finally, heat treatments were applied to unrooted cuttings, which severely affected their rooting ability. Thus, this study developed a hot air treatment to produce V. dahliae‐free olive nursery plants.     

Kinetics of the expression of CD163 and CD107a in the lung and tonsil of pigs after infection with PRRSV-1 strains of different virulence

Veterinary Research Communications - The emergence of virulent strains of porcine reproductive and respiratory syndrome virus (PRRSV), causing atypical and severe outbreaks, has been notified...     

Technological classification of basque cider apple cultivars according to their polyphenolic profiles by pattern recognition analysis

The polyphenolic compositions of 31 Basque cider apple cultivars were determined in pulp, peel, and juice by high-performance liquid chromatography--diode array detection analysis of crude extracts and after thiolysis. Data sets, consisting of individual polyphenol concentrations, total procyanidin content, and the average degree of polymerization of procyanidins, were evaluated by multivariate chemometric techniques, to develop decision rules for classifying apple cultivars technologically into bitter and nonbitter categories. A preliminary study of the data structure was performed by cluster analysis and principal component analysis in each apple material. Bitter apple varieties presented higher contents of flavan-3-ols and/or dihydrochalcones than nonbitter cultivars. Different classification systems for the two categories on the basis of the chemical data were obtained applying several supervised pattern recognition procedures, such as linear discriminant analysis, K-nearest neighbors, soft independent modeling of class analogy, partial least-squares, and multilayer feed forward artificial neural networks. Excellent performance in terms of recognition and prediction abilities for both categories (100% of hits) was achieved in every case (pulp, peel, or juice). Polyphenolic profiles of apple pulp, peel, or juice provide enough information to develop classification criteria for establishing the technological group of apple cultivars (bitter or nonbitter).     

Polyphenolic profiles of Basque cider apple cultivars and their technological properties

The polyphenolic compositions of 31 Basque cider apple cultivars were determined in pulp, peel, and juice by high-performance liquid chromatography with diode array detection analysis of crude extracts and after thiolysis. Total polyphenols are distributed in a wide concentration range depending on the cultivar. Procyanidins are the class of polyphenols that present major concentrations in apple. Their average degrees of polymerization range from 4 to 8 depending on the cultivar. Apple cultivars were technologically classified into bitter and nonbitter categories using different classification systems obtained by applying several pattern recognition techniques, such as principal component analysis, K-nearest neighbors, soft independent modeling of class analogy, partial least-squares, and multilayer feed-forward-artificial neural networks, to apple pulp, peel, or juice data (individual polyphenol concentrations, total procyanidin content, and the average degree of polymerization of procyanidins). Bitter apple cultivars present higher contents of flavan-3-ols and/or dihydrochalcones than nonbitter cultivars. Detailed knowledge of the polyphenolic profile of each apple cultivar affords information about their susceptibility to oxidation, their sensory properties (bitterness, astringency), and their possible influence on the characteristics and quality of the final product (juice, cider) when apples are processed.     

Immunohistochemical detection of extrinsic and intrinsic mediators of apoptosis in porcine paraffin-embedded tissues

Apoptosis is a strictly regulated mechanism of cell death that involves a complex network of biochemical pathways. Whether a cell undergoes apoptosis or not depends on a delicate balance of anti- and pro-apoptotic stimuli. This phenomenon can be induced by two different pathways: intrinsic and extrinsic pathways. The main aim of this study was to determine the ideal fixative and antigen retrieval method in porcine paraffin embedded tissues for the immunohistochemical detection of apoptosis mediators, from both extrinsic and intrinsic pathways. Tonsil, retropharyngeal lymph node and lung tissue samples were fixed in 10% neutral buffered formalin, Bouin solution and zinc salts fixative (ZSF) and different unmasking methods were carried out. Both 10% neutral buffered formalin and ZSF resulted as the fixatives of election to study apoptosis phenomena. Tween 20 (0.01% in PBS), citrate buffer (microwave, pH 6.0) and/or protease type XIV were the antigen retrieval methods which displayed better labelling. Our results allow to deep in the knowledge of apoptosis and its role in the pathogenesis of porcine diseases.     

Variability and selection of verticillium wilt resistant genotypes in cultivated olive and in the Olea genus

Developing verticillium wilt resistant genotypes is currently a major objective in olive breeding. In this study, 6017 genotypes derived from 48 crosses obtained by open pollination and crosses between olive cultivars, wild olive genotypes and other Olea species and Olea europaea subspecies were individually evaluated for verticillium wilt resistance. More than 800 genotypes were identified as resistant to the disease based on the absence of symptoms. High genetic variability and wide segregation in resistance were observed. The inheritance of resistance was studied, and the best parents and crosses to breed resistant genotypes were identified. According to the results, verticillium wilt resistance in olive appears to be a quantitative trait. The results obtained by comparing the level of resistance between different crosses as well as by estimating heritability suggest that it is possible to breed for verticillium wilt resistance in olive.     

Highly infested soils undermine the use of resistant olive rootstocks as a control method of verticillium wilt

Verticillium wilt of olive (VWO) is probably the most devastating fungal disease for olive trees worldwide, and currently the main cultivars are susceptible or moderately susceptible to this disease. The evaluation of resistant cultivars as rootstocks to control the disease has scarcely been explored, and mainly in short-term studies under controlled conditions, which usually do not correspond with field evaluations. The main objective of this study was to assess the responses to VWO of different scion × rootstock combinations of the olive cultivars Picual, Arbequina, Changlot Real, and Frantoio in a long-term field experiment with a soil highly infested with the defoliating pathotype of Verticillium dahliae. The results showed that grafting the susceptible cultivar Picual onto resistant rootstocks delayed the onset of the disease symptoms; however, after 4 years, it was observed that all combinations that contain Picual (a) were extensively colonized by V. dahliae; (b) developed severe symptoms of the disease; and (c) had plant mortality similar to Picual growing on its own roots. This result highlights the importance of long-term field experiments to evaluate VWO and shows that grafting susceptible olive cultivars onto resistant ones does not provide a durable control of VWO under high inoculum potential, as V. dahliae is able to progress through the resistant rootstock and then extensively colonize and kill the susceptible scion. However, the high inoculum potential observed in this study does not allow us to consider the evaluated resistant cultivars as completely ineffective under lower inoculum densities.     

Determination of polyphenolic profiles of Basque cider apple varieties using accelerated solvent extraction

Polyphenols in the peel and pulp of 15 Basque cider apple varieties were determined by accelerated solvent extraction followed by reversed phase high-performance liquid chromatography with diode array detection. It was observed that the polyphenolic composition in apple peel depended on varieties, whereas the main classes of phenolic compounds in apple pulp were flavan-3-ols and hydroxycinnamic acids in all cases, representing both together between 86 and 95% of total polyphenols assayed.     

Enhanced expression of TGFβ protein in lymphoid organs and lung, but not in serum, of pigs infected with a European field isolate of porcine reproductive and respiratory syndrome virus

Transforming growth factor β (TGFβ) is an immunomodulatory cytokine which is able to modulate the host immune response eliciting an inefficient response against pathogens. In this sense, the role of this cytokine in porcine reproductive and respiratory syndrome (PRRS) has been poorly studied and the reported results are contradictory. Thus, in the present study, the expression of TGFβ was analysed both at tissue (lymphoid organs and lung) and serum level to study its correlation with the expression of PRRS virus (PRRSV). To carry out this study, 32 pigs were inoculated with the European PRRSV field isolate 2982 and sequentially killed from 0 dpi to the end of the study (24 dpi). Blood and tissue samples were collected to determine the expression of PRRSV and TGFβ. PRRSV was detected in inoculated animals from 3 dpi until the end of the study, however TGFβ was not detected in sera from inoculated animals. Contrary, an increase of TGFβ antigen was observed both in the lymphoid organs and in the lung of PRRSV-inoculated pigs when compared with control group. Since TGFβ play a role as an immunomodulatory cytokine of the immune response and also in the differentiation of regulatory T cells (Tregs), the upregulation of the TGFβ at tissue level may play a role in the impairment of the host immune response observed during PRRS, being observed a significant correlation between PRRSV and TGFβ expression at lung level.     

Trueness-To-Type and Yield Components of the Banana Hybrid Cultivar FHIA-18 Plants Regenerated Via Somatic Embryogenesis in a Bioreactor

Summary A population of 1,500 plants of the banana hybrid ‘FHIA-18’ (AAAB), regenerated from somatic embryos, which were multiplied in bioreactors, showed similar characteristics to plants propagated from shoot tip cultures both in the acclimatization stage and in field experiments carried out in Cuba. The plants originating from somatic embryos were similar to the plants obtained from shoot tips with respect to plant height, diameter of the pseudostem and number of suckers. Both groups of plants obtained from in vitro cultures were significantly different to the plants obtained from suckers during the flowering period of the mother plants, which was shortened by two months. The greater plant height and diameter of the pseudostem in the plants coming from somatic embryos and shoot tip is due to the effect of in vitro culture, and this was observed in different banana and plantain cultivars. During the second cycle of evaluation, the plants coming from the three propagation methods studied in this work had similar growth habits without significant differences in the majority of the morphological parameters evaluated. These results confirm that the difference obtained during the first cycle between the distinct populations is attributed to temporary changes. The original characteristics of the cultivar were evident from the second cycle of culture. Only 0.13% somaclonal variant was observed in the plants coming from somatic embryogenesis. These percentages are low taking into consideration that other propagated methods accept up to 5% variants in field conditions.