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Doñinos de Salamanca, Spain

Velazquez E.,University of Salamanca | Palomo J.L.,Centro Regional Of Diagnostico | Rivas R.,University of Salamanca | Guerra H.,University of Salamanca | And 6 more authors.
Systematic and Applied Microbiology

Some strains of the former genus Agrobacterium have high biotechnological interest and are currently misclassified. Consequently, in this study, the taxonomic status of the non-pathogenic strain Agrobacterium radiobacter K84, used in biological control, and the tumourigenic strain Agrobacterium tumefaciens AKE10, able to regenerate tobacco transgenic plants, was revised. The phylogenetic analysis of the chromosomal genes rrs, atpD and recA showed that they should be reclassified into Rhizobium rhizogenes. The analysis of virulence genes located in the Ti plasmid (pTi) outside T-DNA showed a common phylogenetic origin among strains AKE10, R. rhizogenes 163C and A. tumefaciens (currently R. radiobacter) C58. However, the genes located inside the T-DNA, mainly the 6b gene, of strain AKE10 were phylogenetically close to those of strain 163C but divergent from those of strain C58. Furthermore, the T-DNA of tumourigenic strains from R. rhizogenes conferred on them the ability to regenerate tumour tissue resembling fasciation in tobacco plants. These results showed the existence of a highly mosaic genetic organization in tumourigenic strains of the genus Rhizobium and provided evidence of the involvement of T-DNA from tumourigenic strains of R. rhizogenes in fasciation of Nicotiana leaves. The data further suggested that pathogenic strains of Rhizobium could be good models to analyse bacterial evolution. © 2010 Elsevier GmbH. Source

Ramirez-Bahena M.-H.,CSIC - Institute of Natural Resources and Agriculture Biology of Salamanca | Ramirez-Bahena M.-H.,University of Salamanca | Flores-Felix J.D.,University of Salamanca | Cuesta M.J.,CSIC - Institute of Natural Resources and Agriculture Biology of Salamanca | And 9 more authors.
Antonie van Leeuwenhoek, International Journal of General and Molecular Microbiology

A bacterial strain designated A4STR04T was isolated from the inner root tissue of potatoes in Spain. Phylogenetic analysis based on the 16S rRNA gene sequence placed the isolate into the genus Fontibacillus, being most closely related to Fontibacillus panacisegetis KCTC 13564T with 99 % identity. The isolate was observed to form Gram-positive, motile and sporulating rods. The catalase test was found to be negative and oxidase positive. Nitrate was found to be reduced to nitrite. β-Galactosidase and caseinase were observed to be produced but the production of gelatinase, urease, arginine dehydrolase, ornithine and lysine decarboxylase was negative. Aesculin hydrolysis was found to be positive and acetoin production was negative. Growth was found to be supported by many carbohydrates and organic acids as carbon source. MK-7 was the only menaquinone detected and the major fatty acid (61.5 %) was identified as anteiso-C15:0, as occurs in the other species of genus Fontibacillus. The strain A4STR04T was found to display a complex lipid profile consisting of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, a glycolipid, two phospholipids, a lipid and two aminophospholipids. Mesodiaminopimelic acid was detected in the peptidoglycan. The G+C content was determined to be 50.5 mol% (Tm). Phylogenetic, chemotaxonomic and phenotypic analyses showed that strain A4STR04T (=LMG 28458 T = CECT 8693T) should be classified as representing a novel species of genus Fontibacillus, for which the name Fontibacillus solani sp. nov. is proposed. © 2015, Springer International Publishing Switzerland. Source

Garcia Benavides P.,Centro Regional Of Diagnostico | Martin Zamorano P.,Centro Regional Of Diagnostico | Ocete PeRez C.A.,University of Seville | Maistrello L.,University of Modena and Reggio Emilia | Ocete Rubio R.,University of Seville
Journal International des Sciences de la Vigne et du Vin

Aim: Grapevine decline caused by wood ftmgi seriously threatens viticulture worldwide. In Spain, the polyphagous borer Xylotrechus arvicola (Coleoptera, Cerambycidae) is becoming a serious pest in different Qualified Designation of Origin (DOC) wine regions. The aim of the present work was to identify the fungal species growing in the galleries excavated by X. arvicola larvae inside the vine branches and investigate the possible relationship between wood pathogenic fungi and this borer. Methods and results: Wood samples from branches of Tempranillo vines and Prunus pisardi trees affected by the borer X. anicola were collected in La Rioja DOC vineyards (Northern Spain) and analyzed for the presence of fungi using both morphological techniques and genetic tools based on lintemal Ttranscribed sSpacer 2 (ITS2) sequence. Among the 20 different fungal species/isolates identified, 7 belonged to fungi associated with grapevine decline (esca, Petri disease, and Eutypa dieback), 6 were plant pathogens, 6 were saprophytic and one was entomopathogenic (Beauveria bassiana). Conclusion: The fact that 65 % of the fungi detected inside X. arvicola galleries belong to species recognized as plant pathogens suggests that this borer, in addition to causing a progressive decay of the branches, could facilitate the transmission of plant diseases, further threatening the vineyards by spreading grapevine decline pathogens. Significance and impact of the study : The present work represents a first step in recognizing the association between the fungal pathogens associated with grapevine decline and the borer X. arvicola, suggesting a possible role of this insect as a vector in the transmission of these fungi. © Vigne et Vin Publications Internationales (Bordeaux, France). Source

Martin-Sanz A.,Leon Institute of Technology | Palomo J.L.,Centro Regional Of Diagnostico | de la Vega M.P.,University of Leon | Caminero C.,Leon Institute of Technology
European Journal of Plant Pathology

A total of 298 bacterial isolates were collected from pea cultivars, landraces and breeding lines in North-Central Spain over several years. On the basis of biochemical-physiological characteristics and molecular markers, 225 of the isolates were identified as Pseudomonas syringae, either pv. pisi (110 isolates) or pv. syringae (112), indicating that pv. syringae is as frequent as pv. pisi as causal agent of bacterial diseases in pea. Most strains (222) were pathogenic on pea. Further race analyses of P. syringae pv. pisi strains identified race 4 (59.1% of the isolates of this pathovar), race 2 (20.0%), race 6 (11.8%), race 5 (3.6%) and race 3 (0.9%). Five isolates (4.6%) showed a not-previously described response pattern on tester pea genotypes, which suggests that an additional race 8 could be present in P. syringae pv. pisi. All the isolates of P. syringae pv. syringae were highly pathogenic when inoculated in the tester pea genotypes, and no significant pathogenic differences were observed. Simultaneous infections with P. syringae pv. pisi and pv. syringae in the same fields were observed, suggesting the importance of resistance to both pathovars in future commercial cultivars. The search for resistance among pea genotypes suitable for production in this part of Spain or as breeding material identified the presence of resistance genes for all P. syringae pv. pisi races except for race 6. The pea cultivars Kelvendon Wonder, Cherokee, Isard, Iceberg, Messire and Attika were found suitable sources of resistance to P. syringae pv. syringae. © 2010 KNPV. Source

Martin-Sanz A.,Leon Institute of Technology | Martin-Sanz A.,University of Sheffield | Palomo J.L.,Centro Regional Of Diagnostico | de la Vega M.P.,University of Leon | Caminero C.,Leon Institute of Technology
European Journal of Plant Pathology

The diploid annual legume species, Lathyrus sativus L., also known as grass pea, and L. cicera L., also known as chickling pea, are neglected species although they are widely grown as pulse crops for human food and also as grain feed or as forage in many of the harshest agro-environments of the world. The surface devoted to these two crops is increasing in Spain, where they were traditionally grown. The presence of bacterial blight among these crops was detected in fields located in the North part of the Central Spanish Meseta during the 2008-9 and 2009-10 seasons. Metabolic-biochemical tests, inoculation experiments in different hosts and molecular markers identified the causal agent as Pseudomonas syringae pv. syringae. This work represents the first description of the occurrence of P. syringae pv. syringae in Lathyrus spp. Bacteria isolated from these two plant species were also pathogenic and very aggressive in other cool season legume species. Rep-PCR patterns showed a close similarity among the P. syringae pv. syringae samples collected within each Lathyrus species, and that the bacterial isolates from Lathyrus spp. were very similar to strains of this pathogen isolated from common and hairy vetch, and from pea. Multilocus sequencing typing confirmed the similarity of one of these isolates with database P. syringae pv. syringae sequences. Most of the L. cicera landraces evaluated for resistance to P. syringae pv. syringae were susceptible or highly susceptible, but some promising resistance sources to this pathogen were found under controlled conditions. © 2012 KNPV. Source

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