First report of bacterial leaf blight caused by Xanthomonas hortorum pv. carotae on carrots in Spain
In September 2019, symptoms resembling those of bacterial leaf blight were observed on carrot plants (Daucus carota L. subsp. sativus Hoffm.) cv. Romance cultivated in commercial plots in Chañe (Segovia), Spain. Symptoms were observed in two plots surveyed representing three hectares, with an inc...
| Autores principales: | , , , , , |
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| Formato: | Artículo preliminar |
| Lenguaje: | Inglés |
| Publicado: |
APS Publications
2021
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| Acceso en línea: | http://hdl.handle.net/20.500.11939/7157 https://doi.org/10.1094/PDIS-11-20-2493-PDN https://apsjournals.apsnet.org/doi/10.1094/PDIS-11-20-2493-PDN |
| _version_ | 1855492227391815680 |
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| author | Palomo, José L. Shima, María Monterde, Adela Navarro-Herrero, Inmaculada Barbé, Silvia Marco-Noales, Ester |
| author_browse | Barbé, Silvia Marco-Noales, Ester Monterde, Adela Navarro-Herrero, Inmaculada Palomo, José L. Shima, María |
| author_facet | Palomo, José L. Shima, María Monterde, Adela Navarro-Herrero, Inmaculada Barbé, Silvia Marco-Noales, Ester |
| author_sort | Palomo, José L. |
| collection | ReDivia |
| description | In September 2019, symptoms resembling those of bacterial leaf blight were observed on
carrot plants (Daucus carota L. subsp. sativus Hoffm.) cv. Romance cultivated in
commercial plots in Chañe (Segovia), Spain. Symptoms were observed in two plots
surveyed representing three hectares, with an incidence greater than 90%, and also in
some plots in other nearby municipalities sown with the same batch of seeds. The lesions
observed at the ends of the leaves were initially yellow that develop dark brown to black
with chlorotic halos on leaflets that turned necrotic. Yellow, Xanthomonas-like colonies
were isolated onto YPGA medium (Ridé 1969) from leaf lesions. Two bacterial isolates
were selected and confirmed by real-time PCR using a specific primer set for
Xanthomonas hortorum pv. carotae (Temple et al. 2013). All isolates were gram-negative,
aerobic rods positive for catalase, able of hydrolyzing casein and aesculin and growing at
2% NaCl, while were negative for oxidase and urease tests. Sequences of 16S rRNA gene
showed 100% similarity with Xanthomonas campestris, X. arboricola, X. gardneri, X.
cynarae strains (GenBank accession numbers: MW077507.1 and MW077508.1 for the
isolates CRD19-206.3 and CRD19-206.4, respectively). However, the resulting phylogeny
of multilocus sequence analysis (MLSA) of a concatenation of the housekeeping genes
atpD, dnaK, and efp (Bui Thi Ngoc et al. 2010), by using neighbour-joining trees generated
with 500 bootstrap replicates, grouped the two isolates with the X. hortorum pv. carotae
M081 strain (Kimbrel et al. 2011) (GenBank accession numbers: MW161270 and
MW161271 for atpD for the two isolates, respectively; MW161268 and MW161269 for
dnaK; MW161272 and MW161273 for efp). A pairwise identity analysis revealed a 100%
identity between all three isolates. Pathogenicity of the isolates was tested by spray
inoculation (Christianson et al. 2015) with a bacterial suspension (108 CFU/ml) prepared in
sterile distilled water at 3 to 4 true-leaf stage (six plants per isolate). Sterile distilled water
Page 1 of 5
was used as negative control. The inoculated plants were incubated in a growth chamber
(25°C and 95% relative humidity [RH]) for 72 h, and then transferred to a greenhouse at 24
to 28°C and 65% RH. Characteristic leaf blight symptoms developed on inoculated carrot
plants, while no symptoms were observed on the negative control plants 20 days after
inoculation. The bacterium was re-isolated from symptomatic tissue and the identity
confirmed through PCR analysis. Based on PCR, morphological and phenotypic tests,
sequence analysis, and pathogenicity assays, the isolates were identified as X. hortorum
pv. carotae. To our knowledge, this is the first report of bacterial leaf blight of carrot
caused by X. hortorum pv. carotae in Spain, and the first molecular and pathological
characterization. It is important to early detect this pathogen and take suitable measures to
prevent its spread, since it could cause yield losses for a locally important crop such as
carrot. |
| format | Artículo preliminar |
| id | ReDivia7157 |
| institution | Instituto Valenciano de Investigaciones Agrarias (IVIA) |
| language | Inglés |
| publishDate | 2021 |
| publishDateRange | 2021 |
| publishDateSort | 2021 |
| publisher | APS Publications |
| publisherStr | APS Publications |
| record_format | dspace |
| spelling | ReDivia71572025-04-25T14:48:11Z First report of bacterial leaf blight caused by Xanthomonas hortorum pv. carotae on carrots in Spain Palomo, José L. Shima, María Monterde, Adela Navarro-Herrero, Inmaculada Barbé, Silvia Marco-Noales, Ester In September 2019, symptoms resembling those of bacterial leaf blight were observed on carrot plants (Daucus carota L. subsp. sativus Hoffm.) cv. Romance cultivated in commercial plots in Chañe (Segovia), Spain. Symptoms were observed in two plots surveyed representing three hectares, with an incidence greater than 90%, and also in some plots in other nearby municipalities sown with the same batch of seeds. The lesions observed at the ends of the leaves were initially yellow that develop dark brown to black with chlorotic halos on leaflets that turned necrotic. Yellow, Xanthomonas-like colonies were isolated onto YPGA medium (Ridé 1969) from leaf lesions. Two bacterial isolates were selected and confirmed by real-time PCR using a specific primer set for Xanthomonas hortorum pv. carotae (Temple et al. 2013). All isolates were gram-negative, aerobic rods positive for catalase, able of hydrolyzing casein and aesculin and growing at 2% NaCl, while were negative for oxidase and urease tests. Sequences of 16S rRNA gene showed 100% similarity with Xanthomonas campestris, X. arboricola, X. gardneri, X. cynarae strains (GenBank accession numbers: MW077507.1 and MW077508.1 for the isolates CRD19-206.3 and CRD19-206.4, respectively). However, the resulting phylogeny of multilocus sequence analysis (MLSA) of a concatenation of the housekeeping genes atpD, dnaK, and efp (Bui Thi Ngoc et al. 2010), by using neighbour-joining trees generated with 500 bootstrap replicates, grouped the two isolates with the X. hortorum pv. carotae M081 strain (Kimbrel et al. 2011) (GenBank accession numbers: MW161270 and MW161271 for atpD for the two isolates, respectively; MW161268 and MW161269 for dnaK; MW161272 and MW161273 for efp). A pairwise identity analysis revealed a 100% identity between all three isolates. Pathogenicity of the isolates was tested by spray inoculation (Christianson et al. 2015) with a bacterial suspension (108 CFU/ml) prepared in sterile distilled water at 3 to 4 true-leaf stage (six plants per isolate). Sterile distilled water Page 1 of 5 was used as negative control. The inoculated plants were incubated in a growth chamber (25°C and 95% relative humidity [RH]) for 72 h, and then transferred to a greenhouse at 24 to 28°C and 65% RH. Characteristic leaf blight symptoms developed on inoculated carrot plants, while no symptoms were observed on the negative control plants 20 days after inoculation. The bacterium was re-isolated from symptomatic tissue and the identity confirmed through PCR analysis. Based on PCR, morphological and phenotypic tests, sequence analysis, and pathogenicity assays, the isolates were identified as X. hortorum pv. carotae. To our knowledge, this is the first report of bacterial leaf blight of carrot caused by X. hortorum pv. carotae in Spain, and the first molecular and pathological characterization. It is important to early detect this pathogen and take suitable measures to prevent its spread, since it could cause yield losses for a locally important crop such as carrot. 2021-03-08T12:36:54Z 2021-03-08T12:36:54Z 2021 acceptedVersion Palomo, J. L., Shima, M., Monterde, A., Navarro, I., Barbé, S., & Marco-Noales, E. First report of bacterial leaf blight caused by Xanthomonas hortorum pv. carotae on carrots in Spain. Plant disease. Published on-line, 23 february 2021. http://hdl.handle.net/20.500.11939/7157 https://doi.org/10.1094/PDIS-11-20-2493-PDN https://apsjournals.apsnet.org/doi/10.1094/PDIS-11-20-2493-PDN en Atribución-NoComercial-SinDerivadas 3.0 España http://creativecommons.org/licenses/by-nc-nd/3.0/es/ openAccess APS Publications electronico |
| spellingShingle | Palomo, José L. Shima, María Monterde, Adela Navarro-Herrero, Inmaculada Barbé, Silvia Marco-Noales, Ester First report of bacterial leaf blight caused by Xanthomonas hortorum pv. carotae on carrots in Spain |
| title | First report of bacterial leaf blight caused by Xanthomonas hortorum pv. carotae on carrots in Spain |
| title_full | First report of bacterial leaf blight caused by Xanthomonas hortorum pv. carotae on carrots in Spain |
| title_fullStr | First report of bacterial leaf blight caused by Xanthomonas hortorum pv. carotae on carrots in Spain |
| title_full_unstemmed | First report of bacterial leaf blight caused by Xanthomonas hortorum pv. carotae on carrots in Spain |
| title_short | First report of bacterial leaf blight caused by Xanthomonas hortorum pv. carotae on carrots in Spain |
| title_sort | first report of bacterial leaf blight caused by xanthomonas hortorum pv carotae on carrots in spain |
| url | http://hdl.handle.net/20.500.11939/7157 https://doi.org/10.1094/PDIS-11-20-2493-PDN https://apsjournals.apsnet.org/doi/10.1094/PDIS-11-20-2493-PDN |
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