Verticillium diseases of vegetable crops in Brazil: Host range,microsclerotia production,molecular haplotype network,and pathogen species determination     

Alba P. Suaste-Dzul  Josiene S. Veloso  Hélcio Costa  Leonardo S. Boiteux  Valdir Lourenço Jr.  Carlos A. Lopes  Ailton Reis 《Plant pathology》2022,71(6):1417-1430

Recent outbreaks of Verticillium wilt diseases in various vegetable crops have been reported in Brazil. This fact was our initial stimulus to carry out a nationwide survey aiming to determine their causal agent(s). Thus far, Verticillium dahliae has been reported as the predominant species based solely on morphological traits. As other Verticillium species can be associated with wilt diseases, we characterized a collection of 80 isolates, collected across 10 agricultural Brazilian regions, by combining morphological, biological, and molecular traits. A multilocus approach was employed for identification of Verticillium species with information from three genomic regions (ribosomal internal transcribed spacer region, glyceraldehyde-3-phosphate dehydrogenase, and actin genes). Only 21 out of the 80 isolates were unable to produce microsclerotia in culture. The analyses of all genomic regions indicated V. dahliae as the sole species associated with vascular wilt of distinct hosts, including major solanaceous vegetables and other hosts such as strawberry, okra, and cacao. Pathogenicity tests confirmed the infection by the V. dahliae isolates and the development of typical disease symptoms on their original hosts. This is the first nationwide characterization of Verticillium isolates associated with major vegetable crops in Neotropical areas. This provides valuable information to design sound management strategies for these diseases, mainly for establishing efficient rotation systems and for the development of resistant cultivars.  相似文献   

Quantitative assessment of the probability of bluetongue virus overwintering by horizontal transmission: application to Germany     

Napp S  Gubbins S  Calistri P  Allepuz A  Alba A  García-Bocanegra I  Giovannini A  Casal J 《Veterinary research》2011,42(1):4

ABSTRACT: Even though bluetongue virus (BTV) transmission is apparently interrupted during winter, bluetongue outbreaks often reappear in the next season (overwintering). Several mechanisms for BTV overwintering have been proposed, but to date, their relative importance remain unclear. In order to assess the probability of BTV overwintering by persistence in adult vectors, ruminants (through prolonged viraemia) or a combination of both, a quantitative risk assessment model was developed. Furthermore, the model allowed the role played by the residual number of vectors present during winter to be examined, and the effect of a proportion of Culicoides living inside buildings (endophilic behaviour) to be explored. The model was then applied to a real scenario: overwintering in Germany between 2006 and 2007. The results showed that the limited number of vectors active during winter seemed to allow the transmission of BTV during this period, and that while transmission was favoured by the endophilic behaviour of some Culicoides, its effect was limited. Even though transmission was possible, the likelihood of BTV overwintering by the mechanisms studied seemed too low to explain the observed re-emergence of the disease. Therefore, other overwintering mechanisms not considered in the model are likely to have played a significant role in BTV overwintering in Germany between 2006 and 2007.  相似文献   

Assessing coincidence between priority conservation areas for vertebrate groups in a Mediterranean hotspot     

Alba Estrada  Raimundo Real  Juan Mario Vargas 《Biological conservation》2011,(3):1120-1129

The effectiveness of selecting umbrella species or groups of species to protect other groups is a key and unresolved issue in conservation planning. We detected areas important to the four groups of terrestrial vertebrates inhabiting Andalusia (southern Spain) according to four conservation-value criteria, i.e., richness, rarity, vulnerability, and endemicity. We calculated coincidences between criteria and taxa by the degree of correlation and fuzzy overlap between the different criteria for the same group (intra-group coincidence) and between the different groups of species for the same criteria (inter-group coincidence). For the groups to be appropriate umbrella species, inter-group coincidence should be high. The results showed that intra-group coincidence was high, but inter-group coincidence was low. Thus, zones of importance to each group of species tended to be located in different places compared to the other groups, and therefore none of them should be used as an indicator or umbrella group to protect the others. This result has implications for conservation policy, as the Andalusian authorities should not assume that protecting a site important to one group of species will also be relevant to conserve the other groups. Nevertheless, we identified the areas of relatively high conjoint importance for all the groups, and the best umbrella group in this region, which proved to be reptiles.  相似文献   

Effects of cryopreservation on germinability of olive (<Emphasis Type="Italic">Olea europaea</Emphasis> L.) pollen     

V. Alba  V. Bisignano  E. Alba  A. De Stradis  G. B. Polignano 《Genetic Resources and Crop Evolution》2011,58(7):977-982

Long term storage of viable pollen is important for bank germplasm constitution to preserve resources that can be used in breeding programs, biotechnologies and genetic engineering. Pollen from 12 olive (Olea europaea L.) cultivars was stored for 1 year in liquid nitrogen at −196°C. The morphology of pollen grains and germination rates on fresh and long term stored pollen were observed. Results on in vitro pollen germinability, both before and after cryopreservation, showed highly significant responses among the 12 cultivars. The relationship between germinability and pollen grain size did not reveal any significant relationships in both treatments. Our findings will contribute to the improvement of olive pollen preservation and lead to find a more efficient method for its long term storage, while retaining its germinability.  相似文献   

Assessment of different surveillance systems for avian influenza in commercial poultry in Catalonia (North-Eastern Spain)     

Alba A  Casal J  Napp S  Martin PA 《Preventive veterinary medicine》2010,97(2):107-118

Compulsory surveillance programmes for avian influenza (AI) have been implemented in domestic poultry and wild birds in all the European Member States since 2005. The implementation of these programmes is complex and requires a close evaluation. A good indicator to assess their efficacy is the sensitivity (Se) of the surveillance system. In this study, the sensitivities for different sampling designs proposed by the Spanish authorities for the commercial poultry population of Catalonia were assessed, using the scenario tree model methodology. These samplings were stratified throughout the territory of Spain and took into account the species, the types of production and their specific risks. The probabilities of detecting infection at different prevalences at both individual and holding level were estimated. Furthermore, those subpopulations that contributed more to the Se of the system were identified. The model estimated that all the designs met the requirements of the European Commission. The probability of detecting AI circulating in Catalonian poultry did not change significantly when the within-holding design prevalence varied from 30% to 10%. In contrast, when the among-holding design prevalence decreased from 5% to 1%, the probability of detecting AI was drastically reduced. The sampling of duck and goose holdings, and to a lesser extent the sampling of turkey and game bird holdings, increased the Se substantially. The Se of passive surveillance in chickens for highly pathogenic avian influenza (HPAI) and low pathogenicity avian influenza (LPAI) were also assessed. The probability of the infected birds manifesting apparent clinical signs and the awareness of veterinarians and farmers had great influence on the probability of detecting AI. In order to increase the probability of an early detection of HPAI in chicken, the probability of performing AI specific tests when AI is suspected would need to be increased.  相似文献   

类似但成土因素不同的土壤：巴西始成土的趋同演变     

Alba L. A. SKORUPA  Sérgio H. G. SILVA  Giovana C. POGGERE  Diego TASSINARI  Leandro C. PINTO  Yuri L. ZINN  Nilton CURI 《土壤圈》2017,27(4):747-757

Soils result from the interaction of five independent formation factors.If one factor varies,while the others remain constant,different soils can be produced.Herein,we demonstrated an opposing trend,wherein two soils were similar,despite considerable differences in all factors of soil formation.We sampled two Inceptisols (Oxic Dystrudepts) formed on different parent materials (gneiss vs.mica schist),climate (tropical altimontane vs.warmer,drier plateau),topography (1 650 m,45％ slope vs.1000 m,8％ slope),time (rejuvenated vs.old,stable surface),and vegetation (rainforest vs.Cerrado savanna).The two soils had similar chemical properties,whereas the soil on mica schist had finer particle size distribution,lower porosity,and lower saturated hydraulic conductivity.These properties were related to a coarser blocky microstructure compared to the soil on gneiss.Both soils presented active mineral weathering and pronounced pedoplasmation,demonstrated by clay contents ＞ 300 g kg-1,although only the Dystrudept on gneiss possessed coarse rock fragments.The C horizons of both soils presented fragmented clay coatings suggestive of argilluviation,likely relict,because they were not observed in the B horizons.The similarities in many properties of the two Dystrudepts,despite contrasting factors of soil formation,suggest converging evolution and that soil classification at the subgroup level was efficient in grouping similar formative processes in tropical conditions.Moreover,this work revealed that similar pedogenic processes acting on different factors of soil formation can result in similar soil properties,at least for Inceptisols where further soil development is hindered by topographic limitations.  相似文献   

Beneath the mistletoe: parasitized trees host a more diverse herbaceous vegetation and are more visited by rabbits     

José A. Hódar  Alba Lázaro-González  Regino Zamora 《Annals of Forest Science》2018,75(3):77

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Influence of different dietary doses of n-3- or n-6-rich vegetable fats and alpha-tocopheryl acetate supplementation on raw and cooked rabbit meat composition and oxidative stability     

Tres A  Bou R  Codony R  Guardiola F 《Journal of agricultural and food chemistry》2008,56(16):7243-7253

This study evaluates the effects of replacing beef tallow added to rabbit feeds (3% w/w) by different doses (0%, 1.5% and 3% w/w) of n-6- or n-3-rich vegetable fat sources (sunflower and linseed oil, respectively) and alpha-tocopheryl acetate supplementation (0 and 100 mg/kg) on the fatty acid composition, alpha-tocopherol content, and oxidation levels [assessed by analyzing thiobarbituric acid (TBA) and lipid hydroperoxide values] in rabbit meat. We also measured these parameters after cooking and refrigerated storage of cooked rabbit meat. Both dietary alpha-tocopheryl acetate supplementation and the dose and source of fat added to feeds influenced meat fatty acid composition, modifying the n-6/n-3 ratio, which was more nutritionally favorable when linseed oil was used. Furthermore, the addition of linseed oil and the supplementation with alpha-tocopheryl acetate enhanced long-chain PUFA biosynthesis. However, the addition of 3% linseed oil increased meat oxidation, and although it was reduced by dietary supplementation with alpha-tocopheryl acetate in raw meat, this reduction was not as effective after cooking. Therefore, dietary supplementation with 1.5% linseed oil plus 1.5% beef tallow and with alpha-tocopheryl acetate would be recommended to improve the nutritional quality of rabbit meat.  相似文献   

Fenhexamid adsorption behavior on soil amended with wine lees     

Pinna MV  Budroni M  Farris GA  Pusino A 《Journal of agricultural and food chemistry》2008,56(22):10824-10828

The adsorption of fenhexamid (FEN) [N-(2,3-dichloro-4-hydroxyphenyl)-1-methylcyclohexanecarboxamide] on vineyard soil amended with wine lees (WL) produced by vinery was studied. The adsorption extent depends on WL fraction. The addition of the centrifuged solid lees (SWL) increases the FEN adsorption on soil. Most likely, the organic insoluble fraction formed mainly by dead fermentation yeasts is responsible for the observed increase. The adsorption measured on some deactivated yeasts of wine fermentation shows that Saccharomyces cerevisiae are the most active in FEN retention. On the other hand, the soil amendment with whole WL decreases considerably the fungicide adsorption. This opposite effect may be the result of FEN hydrophobic bonds with the dissolved organic matter of lees that keeps fungicide in solution. This hypothesis is substantiated by the increased FEN solubility in the supernatant of centrifuged wine lees (LWL). The results of soil column mobility confirm that the elution with LWL increases the mobility of FEN in soil.  相似文献   

Photodegradation of herbicide triasulfuron     

Alba Pusino  Ilaria Braschi  Salvatore Petretto  Carlo Gessa 《Pest management science》1999,55(4):479-481

Triasulfuron was degraded in aqueous solution by ultraviolet irradiation to yield 2-chloroethoxybenzene and (4-methoxy-6-methyl-1,3,5-triazin-2-yl)urea. The reaction followed first-order kinetics. In sunlight, the reaction was slower and afforded these two photoproducts together with 2-amino-4-methoxy-6-methyltriazine and 2-(2-chloroethoxy)benzenesulfonamide. The latter compounds arise from hydrolytic cleavage of the sulfonylurea bridge of triasulfuron because of the acidity of the reaction medium due to the loss of sulfur dioxide. A mechanism which accounts for the formation of the photoproducts is proposed. © 1999 Society of Chemical Industry  相似文献