Virosis en tomate transmitidas por semilla y su control

[ES] Las virosis transmitidas por semilla en el cultivo del tomate crean gran preocupación entre los productores, y son de especial atención en aquellos que se dedican al cultivo de variedades locales donde las semillas se extraen durante la campaña y son empleadas para cultivos posteriores con lo que la infección y dispersión de estos virus es mucho más frecuente. Entre los virus transmitidos por semilla en tomate destacan el virus del mosaico del tomate (ToMV) y el virus del mosaico del pepino dulce (PepMV). Ambos virus se caracterizan por transmitirse, además de por semilla, de manera mecánica fácilmente y son muy estables manteniéndose en los restos del cultivo anterior y en las infraestructuras empleadas durante el manejo del cultivo. Sin embargo, la localización de estos virus en las semillas contaminadas difiere, mientras que PepMV se localiza únicamente de manera superficial, ToMV puede encontrarse además en zonas más internas como en el endospermo. Esto hace que los tratamientos empleados para la desinfección de semillas infectadas con cada uno de estos virus sea distinto: mientras que PepMV puede ser inactivado con tratamientos químicos superficiales, el tratamiento para descontaminar semillas con ToMV debe ser térmico a elevadas temperaturas.[EN] Viral diseases transmitted through seed create a great concern among the tomato producers, especially those who use local varieties that harvest their own seeds from the previous growing season fruits. In this case the infection and spread of seed-transmitted viruses is more usual. ToMV and PepMV are the two main seed-transmitted viruses which affect tomato crops. Both viruses are easily mechanically and seed transmitted, and remain infective in the plant debris of the previous crop and in the crop structures. However, the location of the virus in the contaminated seed is different. PepMV is present only externally in the seed coat, but ToMV could be also found in the endosperm. Therefore seed treatments to inactivate these two viruses are different; while PepMV could be inactivated by external chemical treatments, ToMV infected seeds should be thermal treated in order to eliminate further seedling infections.Alfaro Fernández, AO.; Font San Ambrosio, MI. (2020). Virosis en tomate transmitidas por semilla y su control. En I Congrés de la Tomaca Valenciana: La Tomaca Valenciana d'El Perelló. Editorial Universitat Politècnica de València. 97-114. https://doi.org/10.4995/TOMAVAL2017.2017.6524OCS9711

Inoculation of cucumber, melón and zucchini varieties with Tomato leaf curl New Delhi virus (ToLCNDV) and evaluation of infection using different methods

This is the peer reviewed version of the following article: Figás-Moreno, MDR.; Alfaro Fernández, AO.; Font San Ambrosio, MI.; Borràs Palomares, D.; Casanova-Calancha, C.; Hurtado Ricart, M.; Plazas Ávila, MDLO.... (2017). Inoculation of cucumber, melón and zucchini varieties with Tomato leaf curl New Delhi virus (ToLCNDV) and evaluation of infection using different methods. Annals of Applied Biology. 170(3):405-414. doi:10.1111/aab.12344, which has been published in final form at http://doi.org/10.1111/aab.12344. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.[EN] The disease caused by Tomato leaf curl New Delhi virus (ToLCNDV), which is naturally transmitted by the whitefly Bemisia tabaci, causes important economic losses in cucurbit crops. The availability of simple and efficient inoculation protocols and detection methods is necessary for screening varieties and germplasm collections as well as for breeding populations. We evaluated the infectivity of ToLCNDV inocula prepared using three different buffers for mechanical sap inoculation in a susceptible variety of zucchini. We found that inoculum prepared with buffer III, which contains polyvinylpyrrolidone, is highly efficient for mechanical inoculation, with 100% of plants displaying severe symptoms 21 days post-inoculation. Using this buffer, we mechanically inoculated 19 commercial varieties of cucurbit crops (six of cucumber, six of melon and seven of zucchini), evaluated the evolution of symptoms and diagnosed infection using nine different ToLCNDV detection methods (four based on serology, four based on molecular hybridization and one based on PCR detection). The results revealed that all varieties are susceptible, although cucumber varieties display less severe symptoms than those of melon or zucchini. All detection methods were highly efficient (more than 85% of plants testing positive) in melon and zucchini, but in cucumber, the percentage of positive plants detected with serology and molecular hybridization methods ranged from 20.4% with Squash leaf curl virus (SLCV) antiserum, to 78.5% with DNA extract hybridization. Overall, the best detection results were obtained with PCR, with 92.6%, 92.4% and 98.4% cucumber, melon and zucchini plants, respectively, testing positive. When considering the overall results in the three crops, the best serology and molecular hybridization methods were those using Watermelon chlorotic stunt virus (WmCSV) antiserum and DNA extract, respectively. The inoculation methodology developed and the information on detection methods are of great relevance for the selection and breeding of varieties of cucurbit crops that are tolerant or resistant to ToLCNDV.Figás-Moreno, MDR.; Alfaro Fernández, AO.; Font San Ambrosio, MI.; Borràs Palomares, D.; Casanova-Calancha, C.; Hurtado Ricart, M.; Plazas Ávila, MDLO.... (2017). Inoculation of cucumber, melón and zucchini varieties with Tomato leaf curl New Delhi virus (ToLCNDV) and evaluation of infection using different methods. Annals of Applied Biology. 170(3):405-414. doi:10.1111/aab.12344S405414170

First report of Eggplant mottled dwarf virus in Pittosporum tobira in Spain

Alfaro Fernández, AO.; Córdoba-Sellés, MDC.; Tornos, T.; Cebrián, M.; Font San Ambrosio, MI. (2011). First report of Eggplant mottled dwarf virus in Pittosporum tobira in Spain. Plant Disease. 95(1):75-75. doi:10.1094/PDIS-07-10-0491S757595

Candidatus Liberibacter solanacearum associated with Bactericera trigonica-affected carrots in the Canary Islands

Alfaro Fernández, AO.; Siverio, F.; Cebrian Mico, MC.; Villaescusa, FJ.; Font San Ambrosio, MI. (2012). Candidatus Liberibacter solanacearum associated with Bactericera trigonica-affected carrots in the Canary Islands. Plant Disease. 96(4):581-581. doi:10.1094/PDIS-10-11-0878-PDNS58158196

First Report of Pepper vein yellows virus Infecting Sweet Pepper in Spain

Villanueva, F.; Castillo, P.; Font San Ambrosio, MI.; Alfaro Fernández, AO.; Moriones, E.; Navas-Castillo, J. (2013). First Report of Pepper vein yellows virus Infecting Sweet Pepper in Spain. Plant Disease. 97(9):1261-1261. doi:10.1094/PDIS-04-13-0369-PDN1261126197

Detection of stolbur group (16SrXII) phytoplasma in willow (Salix babylonica).

Copyright of the bulletin (©Bulletin of Insectology). Full text articles are available at the publisher site freely two years after publication.[EN] Preliminary results of nested-PCR indicated that phytoplasmas were detected in willow (Salix babylonica Linn) showing yellows, ball-like structures and small leaves symptoms collected in Valencia Province (Eastern Spain). RFLP analyses showed that the phytoplasmas belonged to the stolbur group (16SrXII).Alfaro Fernández, AO.; Abad Campos, P.; Hernández Llopis, D.; Serrano Fernández, A.; Font San Ambrosio, MI. (2011). Detection of stolbur phytoplasma in willow in Spain. Bulletin of insectology. 64(Supplement):111-112. http://hdl.handle.net/10251/63861S11111264Supplemen

Molecular identification of 16SrII-D subgroup phytoplasmas associated with chickpea and faba bean in Sudan

[EN] In January 2011, symptomatic chickpea and faba bean plants were observed in fields located in the Gezira state (Sudan). Faba bean plants showed yellowing and stunting, whereas chickpea plants presented yellowing, reddening and little leaves. The disease etiology was investigated using nested polymerase chain reaction (PCR) with phytoplasma-specific primers which amplify a fragment of the 16S rRNA gene. Sequencing and restriction fragment length polymorphism (RFLP) analyses revealed that the tested phytoplasmas belonged to the group 16SrII. Phylogenetic analyses of the 16S rRNA gene of the obtained sequences indicated that the chickpea and faba bean phytoplasmas from Sudan were more closely related to the phytoplasmas subgroup 16SrII-D. To our knowledge, this is the first report of phytoplasmas from the group 16SrII-D infecting chickpea in Sudan, and faba bean worldwide.Alfaro Fernández, AO.; Mai Abdala, A.; Abdelraheem, FM.; Saeed, EAE.; Font San Ambrosio, MI. (2012). Molecular identification of 16SrII-D subgroup phytoplasmas associated with chickpea and faba bean in Sudan. European Journal of Plant Pathology. 133(4):791-795. doi:10.1007/s10658-012-9975-7S7917951334Akthar, K. P., Shah, T. M., Atta, B. M., Dickinson, M., Jamil, F. F., Haq, M. A., et al. (2008). Natural occurrence of phytoplasma associated with chickpea phyllody disease in Pakistan—a new record. Plant Pathology, 57, 771.Bertaccini, A., & Duduk, B. (2009). Phytoplasma and phytoplasma diseases: a review of recent research. Phytopathologia Mediterranea, 48, 355–378.Deng, S., & Hiruki, C. (1991). Genetic relatedness between two non-culturable micoplasma-like organisms revealed by nucleic acid hybridization and polymerase chain reaction. Phytopathology, 81, 1475–1479.Green, M. J., & Thompson, D. A. (1999). Easy and efficient DNA extraction from woody plants for the detection of phytoplasmas by polymerase chain reaction. Plant Disease, 83, 482–485.Gundersen, D. E., & Lee, I. M. (1996). Ultrasensitive detection of phytoplasmas by nested-PCR assays using two universal primer pairs. Phytopathologia Mediterranea, 35, 144–151.IRPCM. (2004). “Candidatus Phytoplasma”, a taxon for the wall-less, non-helical prokaryotes that colonize plant phloem and insects. International Journal of Systematic and Evolutionary Microbiology, 54, 1243–1255.Jones, P., & Cockbain, A. J. (1984). Association of a mycoplasma-like organism with broad bean phyllody in the Sudan. Plant Pathology, 33, 599–602.Khan, A. J., Botti, S., Al-Subhi, A. M., Gundersen-Rindal, D. E., & Bertaccini, A. F. (2002). Molecular identification of a new phytoplasma associated with Alfalfa witches’—broom in Oman. Phytopathology, 92, 1038–1047.Lee, I.-M., Gundersen-Rindal, D. E., Davis, R. E., & Bartoszyk, I. M. (1998). Revised classification scheme of phytoplasmas based on RFLP analyses of 16S rRNA and ribosomal protein genes sequences. International Journal of Systematic Bacteriology, 48, 1153–1169.Lee, I. M., Davis, R. E., & Gundersen-Rindal, D. E. (2000). Phytoplasma: phytopathogenic mollicutes. Annual Review of Microbiology, 5, 221–255.Schneider, B., Seemüller, E., Smart, C. D., & Kirkpatrick, B. C. (1995). Phylogenetic classification of plant pathogenic mycoplasma-like organisms or phytoplasmas. In S. Razin & J. G. Tully (Eds.), Molecular and diagnostic procedures in Micoplasmology, vol. 1 (pp. 369–380). San Diego: Academic Press.Schneider, B., Gibb, K. S., & Seemüller, E. (1997). Sequence and RFLP analysis of the elongation factor Tu gene used in differentiation and classification of phytoplasmas. Microbiology, 143, 3381–3389.Tamura, K., Peterson, D., Peterson, N., Stecher, G., Nei, M., & Kumar, S. (2011). MEGA5: molecular evolutionary genetics analysis using maximum likelihood, evolutionary distance, and maximum parsimony methods. Molecular Biology and Evolution, 28, 2731–2739.White, D. T., Blackall, L. L., Scott, T., & Walsh, K. B. (1998). Phylogenetic positions of phytoplasmas associated with dieback, yellow crinkle and mosaic diseases of papaya, and their proposed inclusion in “Candidatus Phytoplasma australiense” and a new taxon “Candidatus Phytoplasma australasia”. International Journal of Systematic Bacteriology, 48, 941–951

Involvement of Olpidium bornovanus and O. virulentus in the occurrence of melon root rot and vine decline caused by Monosporascus cannonballus in central Italy

[EN] Monosporascus root rot and vine decline (MRRVD), caused by Monosporascus cannonballus, has become one of the most important diseases of melon worldwide. Recent evidences suggest that M. cannonballus is not the sole cause of MRRVD, but other pathogens, Olpidium spp. and Melon necrotic spot virus (MNSV) are also involved. The aim of this study was to ascertain the potential concomitant involvement of these pathogens in the development of MRRVD of melon in Central Italy analyzing a soil sampled from a greenhouse with a known history of this disease. O. bornovanus and O. virulentus along with M. cannonballus were identified from the sampled soil. Bait melon plants grown in the contaminated soil were colonized by both Olpidium species and by M. cannonballus, showing roots browning and foliage wilt. No infection by MNSV was detected in bait plants. In the tripartite pathogenicity test, O. bornovanus alone was found to be a virulent pathogen, capable of colonizing roots with a high percentage of colonization intensity, resulting in root browning and foliage wilting. Both disease severity and intensity of Olpidium colonization determined by the co-inoculation of ascospores of M. cannonballus and Olpidium spp. were statistically similar to that resulted by Olpidium or by ascospores separately inoculated. Root symptoms were accompanied by a gradual vine decline and foliage wilting. Root rot and vine decline, which was previously attributed in Central Italy primarily to M. cannonballus, needs to be reattributed, since O. bornovanus and O. virulentus are also involved without apparent synergistic effect among the pathogens.The research was supported by the Department for Innovation in Biological, Agro-food and Forest systems (DIBAF), Viterbo, internal grant. Part of the research was performed by Diana Martignoni within the Lifelong Learning Programme (LLP) - Erasmus Staff Training Work Programme at the Instituto Agroforestal Mediterraneo, Universitat Politecnica de Valencia, Valencia, Spain.Aleandri, M.; Martignoni, D.; Reda, R.; Alfaro Fernández, AO.; Font San Ambrosio, MI.; Armengol Fortí, J.; Chilosi, G. (2017). Involvement of Olpidium bornovanus and O. virulentus in the occurrence of melon root rot and vine decline caused by Monosporascus cannonballus in central Italy. JOURNAL OF PLANT PATHOLOGY. 99(1):169-176. doi:10.4454/jpp.v99i1.3787S16917699