Papers by Ana Palacio-Bielsa
Horticulturae, Jun 1, 2023
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Horticulturae, Apr 5, 2023
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Horticulturae, Feb 3, 2023
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Journal of Plant Pathology, Jul 1, 2009
PCR-based methods offer advantages over more traditional diagnostic tests, in that organisms do n... more PCR-based methods offer advantages over more traditional diagnostic tests, in that organisms do not need to be cultured prior to their detection and protocols are highly sensitive and rapid. Consequently, there is a shift in research towards DNA-based techniques. Although reports already exist on a variety of PCR-based fingerprinting assays used to analyse the genetic diversity of bacterial populations and define their relationships, this review focuses on the general use of PCR in phytobacteriology for detection and diagnosis purposes. An updated and detailed list of published PCR protocols for detection and identification of plant-pathogenic bacteria is presented and discussed, aimed at facilitating access to information that could be particularly useful for diagnostic laboratories. This compilation includes and discusses 246 articles published between 1989 and 2007 addressing 23 genera, more than 50 species, 10 subspecies and more than 40 pathovars.
Phytopathologia Mediterranea, Nov 2, 2012
Erwinia amylovora was detected on pome fruits in the Aragón region (North-Eastern Spain), in a ca... more Erwinia amylovora was detected on pome fruits in the Aragón region (North-Eastern Spain), in a ca. 5 km radius area located in the mid Jalón river (mid Ebro Valley) in the province of Zaragoza, during 2000-2003. Eight years have now passed since this pathogen was last detected, without new infections being reported in the same area. The bases for surveys and rapid eradication performed have been analyzed in detail to understand the reasons for the success in removing fireblight. The results demonstrate that intensive surveillance, risk assessment, plant analyses using accurate identification methods, and, especially, rapid total or selective eradication of infected trees in the plots have been very effective in preventing the generalized spread of fireblight and in delaying economic losses associated with this disease. Eradication and compensation to growers, estimated to cost approx. € 467,000, were clearly counterbalanced by the economic value of apple and pear production in the 2000-2003 period (approx. € 368 million). Fire blight risk-assessment, using the MARYBLYT system, showed that climatic conditions in the studied area were favourable to infections during the analyzed period (1997-2006). Molecular characterization of E. amylovora strains had revealed their homogeneity, suggesting that these fire blight episodes could have been caused by just one inoculum source, supporting the hypothesis that there was a unique introduction of E. amylovora in the studied area. Spatial spread of E. amylovora to trees was analyzed within six orchards, indicating an aggregated distribution model. This Spanish experience demonstrates the success of scientificallybased prevention methods that lead to the deployment of a fast and strict containment strategy, useful for other Mediterranean areas.
First Report on Almond in Europe of Bacterial Spot Disease of Stone Fruits Caused by <i>Xanthomonas arboricola</i> pv. <i>pruni</i>
Plant Disease, Jun 1, 2010
Symptoms characteristic of bacterial spot disease of Prunus spp. (4) were observed on almond tree... more Symptoms characteristic of bacterial spot disease of Prunus spp. (4) were observed on almond trees (Prunus dulcis (Mill.) Webb) in 14 localities of Comunidad Valenciana (eastern Spain) and Aragón (northeastern Spain) between 2006 and 2009. Symptoms were first noted in the spring and were observed until leaf fall. Initial infections began on leaves as small, angular, water-soaked spots, which mainly developed toward the tip and along the leaf margins. These water-soaking lesions were surrounded by chlorotic tissue, although chlorosis did not extend more than a few millimeters. Subsequently, the lesions turned light brown, necrotic, and sometimes the necrotic spots fell out. When the lesions coalesced, they produced large necrotic areas. Sometimes premature leaf drop of infected leaves was observed in severely affected trees. Infected fruits initially displayed sunken, corky lesions that oozed gum, which later became raised when the mesocarp dehydrated. Infected fruits either dropped prematurely or remained on trees after harvest. Cankers typical of bacterial spot disease of stone fruit trees were observed on branches and shoots. Isolations from diseased leaves and fruits yielded Xanthomonas-like colonies on YPGA medium (yeast extract, peptone, and glucose agar), which were subsequently purified and characterized. All strains were gram-negative rods, oxidase negative, and strictly aerobic and showed typical biochemical characteristics of the Xanthomonas genus (3). A collection of 70 strains were further identified by PCR with primers Y17CoF/Y17CoR (1) as Xanthomonas arboricola pv. pruni by comparison with reference strains ISPaVe B4 and ISPaVe B6 isolated from Prunus salicina in Italy. A selection of 46 strains were also analyzed by immunofluorescence (IF) and ELISA using commercial polyclonal antibodies from NEOGEN Europe Ltd. (Ayrshire, Scotland, UK) and SEDIAG S.A.S. (Longvic, France), respectively), although ELISA antibodies proved to be not specific for X. arboricola pv. pruni. Pathogenicity was confirmed by inoculation of 70 almond strains and the reference strains on leaves of potted almond trees and/or on detached leaves (2) with bacterial suspensions (107 CFU per ml). One leaf was inoculated at 8 to 10 sites per strain. Characteristic bacterial spot disease symptoms (4) appeared on all inoculated leaves after 1 week of incubation at 25°C and high humidity, but not on the negative controls infiltrated with sterile distilled water. The original pathogen was reisolated from lesions of inoculated leaves and confirmed by biochemical tests, IF and PCR. As observed in Spain, the disease produces serious damage on the most susceptible almond cultivars like Antoñeta, Guara, Marta, Mas Bovera, and Vayro and can be very harmful, with severity of infection depending upon the relative cultivar susceptibility and environmental conditions. Appropriate eradication measures were taken after the causal agent was confirmed as X. arboricola pv. pruni. This pathogen was previously reported on almond in Japan and New Zealand (4). To our knowledge, this is not only the first report on almond in Spain but also in Europe. References: (1) M. C. Pagani. Ph. D. thesis, North Carolina State University, Raleigh, 2004. (2) P. S. Randhawa and E. L. Civerolo. Phytopathology 75:1060, 1985. (3) L. Vauterin et al. Int. J. Syst. Bacteriol. 45:472, 1995. (4) J. M. Young. N. Z. J. Agric. Res. 20:105, 1977.
La mancha bacteriana de los frutales de hueso en almendro (Xanthomonas arbicola pv. pruni)
International Journal of Systematic and Evolutionary Microbiology, Nov 1, 2017
Four subspecies of Lonsdalea quercina (L. quercina subsp. quercina, L. quercina subsp. britannica... more Four subspecies of Lonsdalea quercina (L. quercina subsp. quercina, L. quercina subsp. britannica, L. quercina subsp. iberica and L. quercina subsp. populi) were studied by genome sequence-derived average nucleotide identity (ANI), phylogenetic analysis based on 16S rRNA gene sequences, multilocus sequence analysis (MLSA) and phenotypic characteristics. In phylogenetic trees, based on 16S rRNA gene sequences, and in MLSA data, the four subspecies were divided into four subclusters in the Lonsdalea clade with high boot strap support. The ANI values between the four subspecies were 88.71-93.38 %, respectively, lower than the proposed species boundary ANI cutoff (95-96 %) that is considered the most important criterion to reclassify these subspecies at the species level. It is proposed that three subspecies be elevated to the species level as Lonsdalea britannica sp. nov. (type strain R-43280 T =LMG 26267 T =NCPPB 4481 T =CFCC 10822 T), Lonsdalea iberica sp. nov.
Fruticultura profesional, 2005
Fire Blight in Aragón: containment measures. Fire Blight, caused by Erwinia amylovora, is one of ... more Fire Blight in Aragón: containment measures. Fire Blight, caused by Erwinia amylovora, is one of the most important diseases affecting plants of the Rosaceae family, including some fruit trees with a great economic value. In Aragón (Spain), the disease was first detected on ornamental plants in 1998, and on fruit trees in year 2000. Up to date, intensive surveys and fast destruction of infected plants adopted measures have been effective in preventing the generalized spread of Fire Blight in Aragón and have allowed preservation of pear and apple production. Fire Blight is still considered as a significant threat for our fruit production.
Plant Disease, Oct 1, 2016
Symptoms of a bacterial disease were observed in nine plantations of hybrid poplar clones (Populu... more Symptoms of a bacterial disease were observed in nine plantations of hybrid poplar clones (Populus × interamericana 'Beaupré,' and Populus × euramericana 'I-214' and 'MC') in five localities of Castilla y León and Aragón (north and northeastern Spain, respectively) in summer 2002, 2014, and 2015. Affected trees were from 9 to 26 years old and disease incidence was up to 30% in some poplar stands. The bark of symptomatic trees was vertically cracked and copious white frothy fluid and creamy slime was observed. Some severely affected trees even died after few years. Isolations from exudates on King's B medium yielded colonies light cream colored, round, slightly A Large-Scale Mutational Analysis of Two-Component Signaling Systems of Lonsdalea quercina Revealed that KdpD-KdpE Regulates Bacterial Virulence Against Host Poplar Trees
European Journal of Plant Pathology, Mar 7, 2010
Six Dickeya spp. strains representative of a larger group of bacteria isolated from potato, onion... more Six Dickeya spp. strains representative of a larger group of bacteria isolated from potato, onion and irrigation water in Spain between years 2003-2005, were characterised by biochemical, serological, molecular and pathogenicity assays. Biochemical and serological differences, as well as pathogenic behaviour in host range and virulence levels, were observed among the strains. They were classified into biovars 3 and 6. Phylogenetic analysis and comparison of the isolates with type strains of Dickeya species characterised to date were performed using concatenated partial sequences of the housekeeping genes gapA and mdh. One of the Spanish strains was identified as D. dieffenbachiae, whereas the other ones did not fit clearly into the previously described six Dickeya species, and may therefore constitute novel species. Isolation of dissimilar pathogenic strains in different rivers and irrigation water sources supports the idea that Dickeya species is commonly present in such an environment, and contaminated water is a potential source of inoculum for the disease in different crops.
Pectobacterium (Erwinia) chrysanthemi en España: caracterización de aislados de patata
Phytoma España: La revista profesional de sanidad vegetal, 2006
Información del artículo Pectobacterium (Erwinia) chrysanthemi en España: caracterización de aisl... more Información del artículo Pectobacterium (Erwinia) chrysanthemi en España: caracterización de aislados de patata.
ITEA, 2016
El azafrán cultivado en España está adquiriendo relevancia en las últimas décadas como producto d... more El azafrán cultivado en España está adquiriendo relevancia en las últimas décadas como producto de gran calidad, lo que requiere la selección de cormos (sus órganos reproductivos) sanos para la plantación con el objetivo de mantener un adecuado estado fitosanitario del cultivo. Este trabajo presenta un estudio del estado fitosanitario del azafrán en Teruel, donde el cultivo fue muy importante económica y socialmente. Además, este estudio pretende ser de utilidad para las zonas productoras con características agroclimáticas similares. Con dichos objetivos, se prospectaron 10 plantaciones comerciales de azafrán en 6 localidades del valle del Jiloca entre los años 2008 y 2011, estudiando la presencia de insectos, ácaros, nematodos, virus, bacterias y malas hierbas. El ácaro Rhizoglyphus robini, una de las plagas más importantes del azafrán, se detectó en los cormos y en el suelo en una parcela. También el nematodo Aphelenchoides blastophtorus, plaga en plantas ornamentales, se encontró abundantemente en cormos de dos parcelas. Se detectaron infecciones ocasionales de virus del género Potyvirus en el cultivo y en la mala hierba Eruca vesicaria. Las malas hierbas Lolium rigidum y Descurainia sophia podrían causar serios problemas de competencia al cultivo y se considera necesario realizar operaciones de escarda en otoño y en invierno. No se detectaron insectos nocivos ni bacterias fitopatógenas. La multiplicación vegetativa del azafrán hace aconsejable realizar muestreos, especialmente en los cormos antes de ser replantados, para detectar la presencia de ácaros, nematodos y virus que podrían ocasionar pérdidas de producción y calidad.
Plant Pathology, Jun 1, 2009
Fifty-six tumorigenic Spanish grapevine strains of Agrobacterium spp. were tested for biovar clas... more Fifty-six tumorigenic Spanish grapevine strains of Agrobacterium spp. were tested for biovar classification, pathogenicity on several hosts, opine utilization, 16S rRNA gene sequencing and PCR amplifications using five primer sets targeting chromosomal and Ti plasmid genes. Fifty of them belonged to A. vitis (biovar 3), three to A. tumefaciens (biovar 1) and three to A. rhizogenes (biovar 2). All strains were tumorigenic on grapevines. Most A. vitis strains were also pathogenic on tomato and tobacco plants, while the three A. tumefaciens strains were only pathogenic on grapevine. Although most A. vitis strains used octopine, 12 utilized neither octopine nor nopaline. 16S rRNA gene sequencing clearly distinguished between strains belonging to the three species. Those of A. vitis could be further divided into three chromosomal backgrounds according to their 16S ribosomal RNA gene sequences. No universal primer pair was found for the detection of all three Agrobacterium species isolated from grapevine. DNA from all A. vitis strains was amplified with the chromosomally-encoded pehA primer pair. In both A. vitis and A. tumefaciens a correlation was observed between the amplifications obtained using the tmr and the virA Ti-plasmid-targeting primer pairs. Three types of Ti plasmid were found in A. vitis strains according to their PCR amplifications and opine utilization profiles. A given chromosomal background harboured only one type of Ti plasmid within the strains from each analysed sample, showing a strong association between chromosomal backgrounds and Ti plasmids in A. vitis .
Archives of Virology, Mar 1, 2004
Seven citrus isolates of Hop stunt viroid (HSVd) were subjected to retrotranscription and DNA amp... more Seven citrus isolates of Hop stunt viroid (HSVd) were subjected to retrotranscription and DNA amplification (RT-PCR), cloning and sequencing. Single stranded polymorphism (SSCP) analysis demonstrated the existence of variability among and within cachexia inducing sources of HSVd. The electrophoretic profiles of SSCP appeared to be able to discriminate between non-cachexia and cachexia sources of HSVd. Sequence analysis demonstrated that the variable (V) domain was very conserved among the cachexia variants. Five nucleotide differences, affecting both the upper (3 nucleotides) and the lower (2 nucleotides) strands of the V domain, were identified as a motif discriminating cachexia and non-cachexia sequences. These five nucleotides affect the organization of a short helical region and two flanking loops of the V domain probably modifying the three-dimensional geometry of the molecule. The stability of the minimum free energy rod-like conformation of the cachexia sequences is lower than the noncachexia. Information regarding the host effect on the evolution and variability of viroid quasispecies is also provided.
Journal of Microbiological Methods, May 1, 2015
Información técnica económica agraria, Mar 1, 2016
El azafrán cultivado en España está adquiriendo relevancia en las últimas décadas como producto d... more El azafrán cultivado en España está adquiriendo relevancia en las últimas décadas como producto de gran calidad, lo que requiere la selección de cormos (sus órganos reproductivos) sanos para la plantación con el objetivo de mantener un adecuado estado fitosanitario del cultivo. Este trabajo presenta un estudio del estado fitosanitario del azafrán en Teruel, donde el cultivo fue muy importante económica y socialmente. Además, este estudio pretende ser de utilidad para las zonas productoras con características agroclimáticas similares. Con dichos objetivos, se prospectaron 10 plantaciones comerciales de azafrán en 6 localidades del valle del Jiloca entre los años 2008 y 2011, estudiando la presencia de insectos, ácaros, nematodos, virus, bacterias y malas hierbas. El ácaro Rhizoglyphus robini, una de las plagas más importantes del azafrán, se detectó en los cormos y en el suelo en una parcela. También el nematodo Aphelenchoides blastophtorus, plaga en plantas ornamentales, se encontró abundantemente en cormos de dos parcelas. Se detectaron infecciones ocasionales de virus del género Potyvirus en el cultivo y en la mala hierba Eruca vesicaria. Las malas hierbas Lolium rigidum y Descurainia sophia podrían causar serios problemas de competencia al cultivo y se considera necesario realizar operaciones de escarda en otoño y en invierno. No se detectaron insectos nocivos ni bacterias fitopatógenas. La multiplicación vegetativa del azafrán hace aconsejable realizar muestreos, especialmente en los cormos antes de ser replantados, para detectar la presencia de ácaros, nematodos y virus que podrían ocasionar pérdidas de producción y calidad.
Applied and Environmental Microbiology, 2011
Xanthomonas arboricola pv. pruni, the causal agent of bacterial spot disease of stone fruit, is c... more Xanthomonas arboricola pv. pruni, the causal agent of bacterial spot disease of stone fruit, is considered a quarantine organism by the European Union and the European and Mediterranean Plant Protection Organization (EPPO). The bacterium can undergo an epiphytic phase and/or be latent and can be transmitted by plant material, but currently, only visual inspections are used to certify plants as being X. arboricola pv. pruni free. A novel and highly sensitive real-time TaqMan PCR detection protocol was designed based on a sequence of a gene for a putative protein related to an ABC transporter ATP-binding system in X. arboricola pv. pruni. Pathogen detection can be completed within a few hours with a sensitivity of 10 2 CFU ml ؊1 , thus surpassing the sensitivity of the existing conventional PCR. Specificity was assessed for X. arboricola pv. pruni strains from different origins as well as for closely related Xanthomonas species, non-Xanthomonas species, saprophytic bacteria, and healthy Prunus samples. The efficiency of the developed protocol was evaluated with field samples of 14 Prunus species and rootstocks. For symptomatic leaf samples, the protocol was very efficient even when washed tissues of the leaves were directly amplified without any previous DNA extraction. For samples of 117 asymptomatic leaves and 285 buds, the protocol was more efficient after a simple DNA extraction, and X. arboricola pv. pruni was detected in 9.4% and 9.1% of the 402 samples analyzed, respectively, demonstrating its frequent epiphytic or endophytic phase. This newly developed real-time PCR protocol can be used as a quantitative assay, offers a reliable and sensitive test for X. arboricola pv. pruni, and is suitable as a screening test for symptomatic as well as asymptomatic plant material. Xanthomonas arboricola pv. pruni (31) (synonym, Xanthomonas campestris pv. pruni [Smith]) is a Gram-negative plant-pathogenic bacterium that causes bacterial spot disease of stone fruits. X. arboricola pv. pruni has been reported to affect a wide range of Prunus species, such as plum, nectarine, peach, apricot, cherry, almond, and ornamental species (19, 26, 32). The disease was first described for Japanese plum in North America in 1903 (28), and since then, it has been reported to occur in many of the major stone-fruit-producing areas of the world (3, 4). Symptoms occur on leaves, fruits, and twigs, ranging from necrotic angular lesions on leaves and sunken lesions on fruits to cankers on twigs. X. arboricola pv. pruni can be very damaging when severe infections occur on highly susceptible cultivars (27). International trade has led to the dissemination of X. arboricola pv. pruni through contaminated material used for propagation (11). Moreover, the bacterium overwinters in buds and leaf scars, which act as efficient sources of primary inocula for spring infections (34). Because of its negative economic impact, X. arboricola pv. pruni is considered a quarantine organ
Microorganisms, Mar 22, 2023
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
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Papers by Ana Palacio-Bielsa