First Report of Alternaria alternata Causing Leaf Spot on Avena nuda in Zhangbei, China

HomePlant DiseaseVol. 105, No. 1First Report of Alternaria alternata Causing Leaf Spot on Avena nuda in Zhangbei, China PreviousNext DISEASE NOTES OPENOpen Access licenseFirst Report of Alternaria alternata Causing Leaf Spot on Avena nuda in Zhangbei, ChinaNa Zhao, Junyu Yang, Qingfang Meng, Xiaoli Fang, Weiwei Zhang, Lingrui Li, Hongfei Yan, and Daqun LiuNa Zhaohttp://orcid.org/0000-0002-4903-5496College of Plant Protection, Agricultural University of Hebei, Technological Innovation Center for Biological Control of Crop Diseases and Insect Pests of Hebei Province Baoding, 071000, ChinaSearch for more papers by this author, Junyu YangCollege of Plant Protection, Agricultural University of Hebei, Technological Innovation Center for Biological Control of Crop Diseases and Insect Pests of Hebei Province Baoding, 071000, ChinaSearch for more papers by this author, Qingfang MengCollege of Plant Protection, Agricultural University of Hebei, Technological Innovation Center for Biological Control of Crop Diseases and Insect Pests of Hebei Province Baoding, 071000, ChinaSearch for more papers by this author, Xiaoli FangCollege of Plant Protection, Agricultural University of Hebei, Technological Innovation Center for Biological Control of Crop Diseases and Insect Pests of Hebei Province Baoding, 071000, ChinaSearch for more papers by this author, Weiwei ZhangCollege of Life Science, Agricultural University of Hebei, Baoding, 071000, ChinaSearch for more papers by this author, Lingrui LiHebei Plant Protection and Plant Inspection Station, Shijiazhuang 050000, ChinaSearch for more papers by this author, Hongfei Yan†Corresponding authors: H. F. Yan; E-mail Address: hongfeiyan2006@163.com and D. Q. Liu; E-mail Address: liudaqun@caas.cnCollege of Plant Protection, Agricultural University of Hebei, Technological Innovation Center for Biological Control of Crop Diseases and Insect Pests of Hebei Province Baoding, 071000, ChinaSearch for more papers by this author, and Daqun Liu†Corresponding authors: H. F. Yan; E-mail Address: hongfeiyan2006@163.com and D. Q. Liu; E-mail Address: liudaqun@caas.cnGraduate School of Chinese Academy of Agricultural Science, Beijing 100081, ChinaSearch for more papers by this authorAffiliationsAuthors and Affiliations Na Zhao1 Junyu Yang1 Qingfang Meng1 Xiaoli Fang1 Weiwei Zhang2 Lingrui Li3 Hongfei Yan1 † Daqun Liu4 † 1College of Plant Protection, Agricultural University of Hebei, Technological Innovation Center for Biological Control of Crop Diseases and Insect Pests of Hebei Province Baoding, 071000, China 2College of Life Science, Agricultural University of Hebei, Baoding, 071000, China 3Hebei Plant Protection and Plant Inspection Station, Shijiazhuang 050000, China 4Graduate School of Chinese Academy of Agricultural Science, Beijing 100081, China Published Online:18 Nov 2020https://doi.org/10.1094/PDIS-03-20-0639-PDNAboutSectionsView articlePDFSupplemental ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmailWechat View articleNaked oats (Avena nuda L.) is an independent species of Avena, which can be used as both food and forage for rich nutritional value. In August 2019, leaf spot was observed at a naked oats planting base in Zhangbei County, Zhangjiakou City, Hebei Province. The incidence of disease was 40 to 50%. The symptoms of the lesions were chlorosis and gradually developing light brown spots with light yellow halos. The spots were irregular, enlarged, and even coalesced to form large areas of necrosis on leaves. To identify the pathogen, 20 symptomatic leaves were collected, and one disease spot was isolated from each samples. Small square leaf pieces (3 to 5 mm) were excised from the junction of diseased and healthy tissues with a sterile scalpel and were sterilized with 75% alcohol for 30 s followed by 0.1% mercuric chloride solution for 1 min, rinsed three times with sterile water, and then transferred onto potato dextrose agar (PDA) at 25°C for 7 days. Four fungal isolates were obtained and purified by the single-spore isolation method. All fungi had the same morphology, and no other fungi were isolated. Colonies of the isolates had round margins and thick fluffy aerial mycelia with brown coloration after 7 days on PDA. Conidiophores were brown, straight or flexuous, septate, single or in clusters. Conidia were obclavate or oval, dark brown, and size ranging from 4.61 to 15.68 × 6.61 to 35.49 μm (n = 100), with longitudinal and transverse septa varying from one to three and from one to seven, respectively. The transverse median septum of the central section was especially thick. On the basis of morphological characteristics, the isolates were identified as Alternaria spp. (Simmons 2007). To further assess the identity of the species, the genomic DNA of pathogenic isolate YM3 was extracted by cetyltrimethylammonium bromide protocol. The ribosomal DNA internal transcribed spacer (ITS) region, the glyceraldehyde-3-phosphate dehydrogenase (GAPDH), the RNA polymerase II second largest subunit (RPB2), and the plasma membrane ATPase genes were amplified and sequenced with primers ITS1/4, gpd1/2, RPB2-6F/7cR, and ATPDF1/ATPDR1, respectively (Nishikawa and Nakashima 2015; Woudenberg et al. 2015). Sequences of ITS, GAPDH, RPB2, and ATPase (MN646900, MT233043, MT233042, and MN640794) of the isolate were 99.82, 99.68, 100, and 99.51% similar to the fungus Alternaria alternata (MK461082.1, MK451978, KP124770.1, and MK804115). A neighbor-joining phylogenetic tree was constructed by combining all sequenced loci in MEGA7. The isolate YM3 clustered in the A. alternata clade with 100% bootstrap support. Therefore, the pathogen was identified as A. alternata based on the morphological characteristics and molecular identification. A pathogenicity test of the A. alternata isolates was performed by placing mycelial disks (5 mm) with conidia on the surface of the first unfolding leaves of naked oats. Each leaf was inoculated with three disks. The pathogenicity test was repeated four times, and 10 leaves were inoculated in each repetition; sterile PDA was used as the control. All treated plants were placed in a moist chamber (25°C, 16-h light and 8-h dark period). Leaf spot symptoms developed on the inoculated plants about 10 days post inoculation, whereas all control plants remained healthy. Similar isolates were reisolated from the inoculated and infected leaves and identified as A. alternata by DNA sequencing, fulfilling Koch’s postulates. It has been reported that A. alternata can cause leaf spots on A. sativa (Chen et al. 2020). However, to our knowledge, this is the first report of A. alternata causing leaf spots on A. nuda in China. It can be concluded that A. alternata can cause leaf spot disease of oats (A. sativa and A. nuda). The spots disease is worthy of our attention for its harm to the production of oats.The author(s) declare no conflict of interest.References:Chen, H., et al. 2020. Plant Dis. 104:1544. https://doi.org/10.1094/PDIS-08-19-1692-PDN Link, ISI, Google ScholarNishikawa, J., and Nakashima, C. 2015. Mycoscience 56:141. https://doi.org/10.1016/j.myc.2014.05.001 Google ScholarSimmons, E. G. 2007. Alternaria: An Identification Manual. CBS Fungal Biodiversity Center, Utrecht, The Netherlands. Google ScholarWoudenberg, J. H. C., et al. 2015. Stud. Mycol. 82:1. https://doi.org/10.1016/j.simyco.2015.07.001 Google ScholarN. Zhao, Q. F. Meng, X. L. Fang, and L. R. Li contributed equally to this work.The author(s) declare no conflict of interest.Funding: Funding was provided by National Program on Key Basic Research Project (2013CB127700, 2017YFD0300906, and 2018YFD0300502), Natural Science Foundation of Hebei Province (C2019204040), Industrial System of Hebei Province (HBCT2018010204), Traditional Chinese Medicine Industry System (HBCT2018060204), and Key Projects of Education Department (ZD2019130).DetailsFiguresLiterature CitedRelated Vol. 105, No. 1 January 2021SubscribeISSN:0191-2917e-ISSN:1943-7692 DownloadCaptionTypical symptoms of star anise spot disease caused by Alternaria tenuissima (J.-L. Lai et al.). Photo credit: J.-L. Lai. Water drops rolling over a strawberry leaf blade with a sporulating lesion of powdery mildew (B. Asalf et al.). Photo credit: B. Asalf. Metrics Article History Issue Date: 8 Jan 2021Published: 18 Nov 2020First Look: 4 Aug 2020Accepted: 1 Aug 2020 Page: 218 Information© 2021 The American Phytopathological SocietyFundingNational Program on Key Basic Research ProjectGrant/Award Number: 2013CB127700Grant/Award Number: 2017YFD0300906Grant/Award Number: 2018YFD0300502Natural Science Foundation of Hebei ProvinceGrant/Award Number: C2019204040Industrial System of Hebei ProvinceGrant/Award Number: HBCT2018010204Traditional Chinese Medicine Industry SystemGrant/Award Number: HBCT2018060204Key Projects of Education DepartmentGrant/Award Number: ZD2019130KeywordsAvena nuda L.Alternaria alternatafungiThe author(s) declare no conflict of interest.PDF downloadCited byIsolation and identification of Tussilago farfara leaf spot caused by Alternaria alternata in ChinaMicrobial Pathogenesis, Vol. 172Environmental and sensitization variations among asthma and/or rhinitis patients between 2008 and 2018 in China2 February 2022 | Clinical and Translational Allergy, Vol. 12, No. 2First Report of Alternaria alternata Causing Leaf Spot of Tartary Buckwheat in ChinaShaoqing Li, Quan Shen, Haihua Wang, Feng He, Zuyin Xiao, Xixu Peng, Meiliang Zhou, and Xinke Tang9 November 2021 | Plant Disease, Vol. 105, No. 11