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First Report of Quinoa Downy Mildew Caused by Peronospora variabilis in Republic of Korea.
Plant Dis 2014; 98(7):1003PD

Abstract

Quinoa (Chenopodium quinoa Willd.) has become increasingly popular due to its high nutritional value and adaptability to harsh environments. Several field trials have recently been conducted to determine the ability of quinoa cultivars to grow under climate and soil conditions of Republic of Korea. During July 2013, which is the rainy season, plants showing typical symptoms of downy mildew were first observed in an experimental plot in Iksan City, Korea. Infection resulted in small to large, irregular chlorotic areas on the upper leaf surface with a gray mildew developing on the abaxial surface, and often leading to early defoliation. The same symptoms of downy mildew were also found in Pyeongchang County and Imsil County, Korea. A sample from Iksan City was deposited in the Korea University Herbarium (Accession No. KUS-F27388) and used for microscopy and molecular studies. Microscopic examination revealed colorless conidiophores emerging from stomata, straight to slightly curved, 350 to 550 × 10 to 18 μm, and sub-dichotomously branched in 5 to 7 orders. Ultimate branchlets were mostly in pairs, flexuous to curved, 10 to 30 μm long, and had obtuse tips. Conidia were pale brown to olivaceous, broadly ellipsoidal to ellipsoidal, and 25 to 32 × 22 to 25 μm with a length/width ratio of 1.20 to 1.35. These characteristics fit well with Peronospora variabilis, which was previously recorded to be parasitic to C. quinoa and C. album, although P. farinosa f. sp. chenopodii has often been considered a causal agent of downy mildew on quinoa (1). To confirm this morphological identification, amplification and sequencing of the internal transcribed spacer (ITS) region of the rDNA of the Korean specimen were performed using procedures outlined by Choi et al. (1) with oomycete-specific primers DC6 and LR0. The resulting 796-bp sequence was deposited in GenBank (Accession No. KF887493). A comparison with the ITS sequences available in GenBank revealed that it is identical to P. variabilis found on C. album (EF614959, EF614961), and shows only one base pair substitution with another isolates from C. quinoa (EU113305, EU113306). Therefore, the pathogen found in Korea was confirmed to be P. variabilis. Downy mildew is the most damaging disease of quinoa in Argentina, Bolivia, Colombia, Ecuador, and Peru (1). Increasing reports of this disease from India, Canada, the United States, Portugal, and Denmark (2,3,4) have revealed its worldwide occurrence and spread. To our knowledge, this is the first report of a downy mildew on quinoa in Korea (3). It suggests that quinoa downy mildew poses a new and serious threat to production of this crop in Korea. References: (1) Y. J. Choi et al. Mycopathologia 169:403, 2010. (2) S. Danielson et al. Seed Sci. Technol. 32:91, 2004. (3) D. F. Farr and A. Y. Rossman. Fungal Databases. Syst. Mycol. Microbiol. Lab., Online publication, ARS, USDA, Retrieved November 5, 2013. (4) A. L. Testen et al. Plant Dis. 96:146, 2012.

Authors+Show Affiliations

Biodiversity and Climate Research Centre (BiK-F), Johann Wolfgang Goethe University in Frankfurt am Main, Germany.Jeollabuk-do Agricultural Research and Extension Services (JBARES), Iksan 570-704, Korea.Highland Agriculture Research Center, Pyeongchang 232-955, Korea.Division of Environmental Science and Ecological Engineering, Korea University, Seoul 136-701, Korea.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

30708864

Citation

Choi, Y J., et al. "First Report of Quinoa Downy Mildew Caused By Peronospora Variabilis in Republic of Korea." Plant Disease, vol. 98, no. 7, 2014, p. 1003.
Choi YJ, Choi IY, Kim JS, et al. First Report of Quinoa Downy Mildew Caused by Peronospora variabilis in Republic of Korea. Plant Dis. 2014;98(7):1003.
Choi, Y. J., Choi, I. Y., Kim, J. S., & Shin, H. D. (2014). First Report of Quinoa Downy Mildew Caused by Peronospora variabilis in Republic of Korea. Plant Disease, 98(7), p. 1003. doi:10.1094/PDIS-12-13-1209-PDN.
Choi YJ, et al. First Report of Quinoa Downy Mildew Caused By Peronospora Variabilis in Republic of Korea. Plant Dis. 2014;98(7):1003. PubMed PMID: 30708864.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - First Report of Quinoa Downy Mildew Caused by Peronospora variabilis in Republic of Korea. AU - Choi,Y J, AU - Choi,I Y, AU - Kim,J S, AU - Shin,H D, PY - 2019/2/3/entrez PY - 2014/7/1/pubmed PY - 2014/7/1/medline SP - 1003 EP - 1003 JF - Plant disease JO - Plant Dis. VL - 98 IS - 7 N2 - Quinoa (Chenopodium quinoa Willd.) has become increasingly popular due to its high nutritional value and adaptability to harsh environments. Several field trials have recently been conducted to determine the ability of quinoa cultivars to grow under climate and soil conditions of Republic of Korea. During July 2013, which is the rainy season, plants showing typical symptoms of downy mildew were first observed in an experimental plot in Iksan City, Korea. Infection resulted in small to large, irregular chlorotic areas on the upper leaf surface with a gray mildew developing on the abaxial surface, and often leading to early defoliation. The same symptoms of downy mildew were also found in Pyeongchang County and Imsil County, Korea. A sample from Iksan City was deposited in the Korea University Herbarium (Accession No. KUS-F27388) and used for microscopy and molecular studies. Microscopic examination revealed colorless conidiophores emerging from stomata, straight to slightly curved, 350 to 550 × 10 to 18 μm, and sub-dichotomously branched in 5 to 7 orders. Ultimate branchlets were mostly in pairs, flexuous to curved, 10 to 30 μm long, and had obtuse tips. Conidia were pale brown to olivaceous, broadly ellipsoidal to ellipsoidal, and 25 to 32 × 22 to 25 μm with a length/width ratio of 1.20 to 1.35. These characteristics fit well with Peronospora variabilis, which was previously recorded to be parasitic to C. quinoa and C. album, although P. farinosa f. sp. chenopodii has often been considered a causal agent of downy mildew on quinoa (1). To confirm this morphological identification, amplification and sequencing of the internal transcribed spacer (ITS) region of the rDNA of the Korean specimen were performed using procedures outlined by Choi et al. (1) with oomycete-specific primers DC6 and LR0. The resulting 796-bp sequence was deposited in GenBank (Accession No. KF887493). A comparison with the ITS sequences available in GenBank revealed that it is identical to P. variabilis found on C. album (EF614959, EF614961), and shows only one base pair substitution with another isolates from C. quinoa (EU113305, EU113306). Therefore, the pathogen found in Korea was confirmed to be P. variabilis. Downy mildew is the most damaging disease of quinoa in Argentina, Bolivia, Colombia, Ecuador, and Peru (1). Increasing reports of this disease from India, Canada, the United States, Portugal, and Denmark (2,3,4) have revealed its worldwide occurrence and spread. To our knowledge, this is the first report of a downy mildew on quinoa in Korea (3). It suggests that quinoa downy mildew poses a new and serious threat to production of this crop in Korea. References: (1) Y. J. Choi et al. Mycopathologia 169:403, 2010. (2) S. Danielson et al. Seed Sci. Technol. 32:91, 2004. (3) D. F. Farr and A. Y. Rossman. Fungal Databases. Syst. Mycol. Microbiol. Lab., Online publication, ARS, USDA, Retrieved November 5, 2013. (4) A. L. Testen et al. Plant Dis. 96:146, 2012. SN - 0191-2917 UR - https://www.unboundmedicine.com/medline/citation/30708864/First_Report_of_Quinoa_Downy_Mildew_Caused_by_Peronospora_variabilis_in_Republic_of_Korea_ L2 - http://apsjournals.apsnet.org/doi/full/10.1094/PDIS-12-13-1209-PDN?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub=pubmed DB - PRIME DP - Unbound Medicine ER -