First Report of Coniella javanica Causing Blight on Roselle Leaves and Calyx in Guerrero, Mexico

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3/26/23, 5:31 PM
First Report of Coniella javanica Causing Blight on Roselle Leaves and Calyx in Guerrero, Mexico | Plant Disease
https://apsjournals.apsnet.org/doi/10.1094/PDIS-09-18-1609-PDN
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DISEASE NOTES
First Report of Coniella javanica Causing Blight on
Roselle Leaves and Calyx in Guerrero, Mexico
A. K. Barrón-Coronado, V. Ayala-Escobar, S. G. Leyva-Mir, C. Nava-Díaz, S. Aranda-Ocampo, and
J. Hernández-Morales
Aliations 
Authors and Aliations
A. K. Barrón-Coronado
V. Ayala-Escobar
S. G. Leyva-Mir
C. Nava-Díaz
S. Aranda-Ocampo
J. Hernández-Morales
Postgrado en Fitosanidad-Fitopatología, Colegio de Postgraduados, Texcoco, 56230, Estado de
México, México; and
Departamento de Parasitología Agrícola, Universidad Autónoma Chapingo, Texcoco, 56230,
Estado de México, México
Roselle (Hibiscus sabdaria L.) is an annual plant, grown mainly for the use of its calyx in fresh
drink production and in medicine as an antihypertensive and diuretic (Herrera-Arellano et al.
2007). During the summer of 2016, symptoms of leaf and calyx blight were observed in
commercial roselle plantations located in Guerrero, the main producing state in Mexico. In
December 2016, incidence of leaf and calyx blight in roselle was 100% for all production areas
in Ayutla, Guerrero, México. The initial symptoms in leaves and calyces consisted of irregular,
light brown leaf spots, which later increased in size causing a necrosis with the presence of
pycnidia. In advanced stages of the disease, a general wilting of the plant was observed.
Calyces and leaves with symptoms of the disease were collected from ve elds. The samples
were disinfested with 1% sodium hypochlorite, washed in autoclaved distilled water, and
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Published Online:26 Feb 2019 https://doi.org/10.1094/PDIS-09-18-1609-PDN

3/26/23, 5:31 PM
First Report of Coniella javanica Causing Blight on Roselle Leaves and Calyx in Guerrero, Mexico | Plant Disease
https://apsjournals.apsnet.org/doi/10.1094/PDIS-09-18-1609-PDN
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cultured in Petri dishes with potato dextrose agar medium. The plates were incubated at 25°C
for 9 days in darkness. Forty-seven colonies that were recovered belong to the same
morphotype. Fungal colonies produced white mycelium in a concentric ring pattern. Pycnidia
were solitary, globose, black, and 315 to 380 μm in diameter. The conidia were unicellular,
ellipsoidal to fusiform, hyaline to brown, and 11.5 to 13.5 × 3.2 to 4.6 μm. The conidiophores
were light brown, densely aggregated, and ramied. These morphological characteristics were
consistent with those described for Coniella javanica (Alvarez et al. 2016). A representative
isolate was deposited in the Culture Collection of Phytopathogenic Fungi at the Postgrado en
Fitosanidad-Fitopatología, Colegio de Postgraduados, Montecillo, as GUE-29. For molecular
identication, the internal transcribed spacer (ITS) region and part of the 28S rRNA and
translation elongation factor 1-α (EF1-α) genes were amplied by polymerase chain reaction
and sequenced using the primer sets ITS1/ITS4 (White et al. 1990), LR0R/LR7 (Rehner and
Samuels 1994), and EF1-728F/EF1-986R (Carbone and Kohn 1999), respectively. The sequences
were deposited in GenBank (accession nos. ITS, MH503948; 28S, MH578600; and EF1-α,
MH613977). A phylogenetic analysis using maximum likelihood and including published ITS,
28S, and EF1-α sequences for C. javanica and other Coniella species was carried out. The
phylogenetic analysis showed that the GUE-29 isolate belongs to the C. javanica clade. The
pathogenicity test was carried out by inoculating 10 leaves and 10 calyces of 10 plants of
roselle variety Tecoanapa that were 4 months old with a suspension of 10 spores/ml of the
representative isolate. Ten leaves and 10 calyces of 10 plants were sprayed with sterile distilled
water as a control. The plants were kept in a greenhouse at 25°C for 12 days; after that time, all
the plants that were inoculated with the fungus developed a leaf and calyx blight and the
presence of pycnidia, whereas on the control plants no symptoms were observed. The
pathogen was reisolated from plants that developed symptoms, and it was morphologically
identied as C. javanica. To the best of our knowledge, this is the rst report of C. javanica
causing leaf and calyx blight in roselle plants in Mexico. This pathogen has previously been
reported causing leaf spot on roselle leaves in Indonesia (Alvarez et al. 2016).
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3/26/23, 5:31 PM
First Report of Coniella javanica Causing Blight on Roselle Leaves and Calyx in Guerrero, Mexico | Plant Disease
https://apsjournals.apsnet.org/doi/10.1094/PDIS-09-18-1609-PDN
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