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First Report of Bacterial Wilt Caused by Ralstonia solanacearum Phylotype IIB Sequevar 1 Affecting Tomato in Different Regions of Chile

2020; American Phytopathological Society; Volume: 104; Issue: 7 Linguagem: Inglês

10.1094/pdis-01-20-0181-pdn

1943-7692

Ingrid Nicole Vásconez, Ximena Besoaín, P. Vega-Celedón, Miryam Valenzuela, Michael Seeger,

Plant Pathogens and Fungal Diseases

HomePlant DiseaseVol. 104, No. 7First Report of Bacterial Wilt Caused by Ralstonia solanacearum Phylotype IIB Sequevar 1 Affecting Tomato in Different Regions of Chile PreviousNext DISEASE NOTES OPENOpen Access licenseFirst Report of Bacterial Wilt Caused by Ralstonia solanacearum Phylotype IIB Sequevar 1 Affecting Tomato in Different Regions of ChileI. N. Vasconez, X. Besoain, P. Vega-Celedón, M. Valenzuela, and M. SeegerI. N. VasconezLaboratorio de Microbiología Molecular y Biotecnología Ambiental, Departamento de Química & Centro de Biotecnología Daniel Alkalay Lowitt, Universidad Técnica Federico Santa María, Valparaíso, Chile, X. Besoainhttp://orcid.org/0000-0002-4861-7961Escuela de Agronomía, Pontificia Universidad Católica de Valparaíso, Quillota, Chile, P. Vega-CeledónLaboratorio de Microbiología Molecular y Biotecnología Ambiental, Departamento de Química & Centro de Biotecnología Daniel Alkalay Lowitt, Universidad Técnica Federico Santa María, Valparaíso, Chile, M. Valenzuela†Corresponding authors: M. Valenzuela; E-mail Address: mvalenzuelao@yahoo.com and M. Seeger; E-mail Address: michael.seeger@usm.clhttp://orcid.org/0000-0002-6475-1597Laboratorio de Microbiología Molecular y Biotecnología Ambiental, Departamento de Química & Centro de Biotecnología Daniel Alkalay Lowitt, Universidad Técnica Federico Santa María, Valparaíso, Chile, and M. Seeger†Corresponding authors: M. Valenzuela; E-mail Address: mvalenzuelao@yahoo.com and M. Seeger; E-mail Address: michael.seeger@usm.clLaboratorio de Microbiología Molecular y Biotecnología Ambiental, Departamento de Química & Centro de Biotecnología Daniel Alkalay Lowitt, Universidad Técnica Federico Santa María, Valparaíso, Chile AffiliationsAuthors and Affiliations I. N. Vasconez1 X. Besoain2 P. Vega-Celedón1 M. Valenzuela1 † M. Seeger1 † 1Laboratorio de Microbiología Molecular y Biotecnología Ambiental, Departamento de Química & Centro de Biotecnología Daniel Alkalay Lowitt, Universidad Técnica Federico Santa María, Valparaíso, Chile 2Escuela de Agronomía, Pontificia Universidad Católica de Valparaíso, Quillota, Chile Published Online:12 May 2020https://doi.org/10.1094/PDIS-01-20-0181-PDNAboutSections ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmailWechat In Chile, the phytopathogenic bacterium Ralstonia solanacearum was first reported affecting potato plants in 1983 (Ciampi-Panno 1984). R. solanacearum was detected first in the tomato crop by Servicio Agrícola y Ganadero de Chile (SAG) (Acuña 2008). Wilt symptoms in tomato have been reported from growers sporadically in northern and central Chile, with more frequent reports in recent years. From June 2017 to December 2019, samples of diseased tomatoes (Solanum lycopersicum) were collected from Azapa Valley from the northern region of Arica y Parinacota (desertic climate) and in central Chile (warm and template climate), in the localities of Quillota and Olmué from Valparaíso Region, and Pichidegua from O'Higgins Region. Affected tomato plants exhibited yellowing and generalized leaf wilting, stunting, and brown coloration of vascular tissues. Vascular tissues of symptomatic plants were macerated, and the suspension was spread on Kelman's tetrazolium medium, resulting in white mucoid colonies with pink centers, which are typical of R. solanacearum strains (Champoiseau et al. 2009). These types of isolates were found in all sampled localities. Molecular identification was carried out by partial 16S rRNA gene sequencing (GenBank accession nos. MN973781 to MN973787). BLAST analysis of all isolates resulted in a match with a 100% identity with R. solanacearum strain UY031 (GenBank: CP012687.1). Polymerase chain reaction (PCR) with specific primers (759: 5′-GTCGCCGTCAACTCACTTTCC-3′ and 760: 5′-GTCGCCGTCAGCAATGCGGAATCG-3′) corroborated the identification of the isolates as R. solanacearum by amplification of a 280-bp "universal" R. solanacearum-specific reference band (Opina et al. 1997). All the isolates were identified as R. solanacearum phylotype II by PCR of the 16S-23S internal transcribed spacer (718 bp) with the primer set RS-1-F: 5′-ACTAACGAAGCAGAGATGCATTA-3′ and RS-1-R: 5′-CCCAGTCACGGCAGAGACT-3′ (Pastrik et al. 2002). A PCR was performed using the primer set 630-F: 5′-ATACAGAATTCGACCGGCACG-3′ and 631-R: 5′-AATCACATGCAATTCGCCTACG-3′, which amplified in all isolates a 357-bp fragment corresponding to phylotype IIB, sequevar 1, historically known as race 3, biovar 2 (Fegan et al. 1998). Pathogenicity assay was performed in susceptible tomato plants (cv. San Pedro) by wounding the center of the stem with a sterile syringe and inoculating 10 µl of a cell suspension of each isolate, previously adjusted to an optical density of 0.1 (λ = 660 nm; ∼108 CFU/ml). Negative controls were inoculated with sterile water. Test plants were incubated at 25°C. The inoculated plants showed severe wilting and bacterial ooze emerging from the inoculation spot after 6 to 12 days. Control plants remained asymptomatic. Strains were reisolated from symptomatic plants and identified as R. solanacearum in the same way as described previously. These results showed that the causal agent of bacterial wilt of tomato in all sampled localities is R. solanacearum phylotype IIB sequevar 1. To our knowledge, this is the first report of Koch's postulates for R. solanacearum on tomato plants in Chile. This report is of concern not only because it is affecting tomato crops but also because this pathogen is quarantined in the south of Chile, the most important area of potato cultivation, where certified potatoes are produced, and the region of origin of part of the cultivars of potato worldwide. Strategies should be implemented to prevent the spread of this pathogen to southern Chile.The author(s) declare no conflict of interest.References:Acuña, R. 2008. Compendio de fitopatógenos de cultivos agrícolas en Chile. Servicio Agrícola y Ganadero, Santiago, Chile. Google ScholarChampoiseau, P. G., et al. 2009. Plant Health Prog. 10. doi: 10.1094/PHP-2009-0313-01-RV. doi.org/10.1094/PHP-2009-0313-01-RV Link, Google ScholarCiampi-Panno, L. 1984. Plant Dis. 68:822. https://doi.org/10.1094/PD-68-822 Crossref, ISI, Google ScholarFegan, M., et al. 1998. Page 34 in: Bacterial Wilt Disease. Springer, Berlin, Germany. https://doi.org/10.1007/978-3-662-03592-4_5 Crossref, Google ScholarOpina, N., et al. 1997. Asia-Pac. J. Mol. Biol. 5:19. ISI, Google ScholarPastrik, K.-H., et al. 2002. Eur. J. Plant Pathol. 108:831. https://doi.org/10.1023/A:1021218201771 Crossref, ISI, Google ScholarThe author(s) declare no conflict of interest.Funding: This study was supported by Universidad Técnica Federico Santa María PhD fellowship (INV), USM PI_IN_19_07 (MS, PVC), and Comisión Nacional de Investigación Científica y Tecnológica Programa de Investigación Asociativa (PIA) Anillo GAMBIO ACT172128 (MS, MV).DetailsFiguresLiterature CitedRelated Vol. 104, No. 7 July 2020SubscribeISSN:0191-2917e-ISSN:1943-7692 DownloadCaptionA cucumber plant with a light gray lesion of charcoal rot at the soil line and microsclerotia visible on the stem (D. S. Egel et al.). Photo credit: D. S. Egel. Rot and discolored sepals of persimmon fruit caused by Mucor inaequisporus (S.-Y. Lee and H.-Y. Jung). Photo credit: H.-Y. Jung. Metrics Downloaded 1,192 times Article History Issue Date: 2 Jul 2020Published: 12 May 2020First Look: 11 Mar 2020Accepted: 9 Mar 2020 Page: 2023 Information© 2020 The American Phytopathological SocietyFundingUniversidad Técnica Federico Santa MaríaGrant/Award Number: PhD fellowshipGrant/Award Number: PI_IN_19_07Comisión Nacional de Investigación Científica y TecnológicaGrant/Award Number: Programa de Investigación Asociativa (PIA) Anillo GAMBIO ACT172128KeywordsRalstonia solanacearumtomatofirst reportChileThe author(s) declare no conflict of interest.