First Report of Leptosphaeria biglobosa Causing Blackleg of Ornamental Kale (Brassica oleracea var. acephala) in China

HomePlant DiseaseVol. 103, No. 4First Report of Leptosphaeria biglobosa Causing Blackleg of Ornamental Kale (Brassica oleracea var. acephala) in China PreviousNext DISEASE NOTES OPENOpen Access licenseFirst Report of Leptosphaeria biglobosa Causing Blackleg of Ornamental Kale (Brassica oleracea var. acephala) in ChinaK. Zhou, Y. H. Yang, M. D. Wu, and G. Q. LiK. ZhouThe State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, 430070, Hubei, China; and The Key Laboratory of Plant Pathology of Hubei Province, Huazhong Agricultural University, Wuhan, 430070, Hubei, ChinaSearch for more papers by this author, Y. H. YangThe State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, 430070, Hubei, China; and The Key Laboratory of Plant Pathology of Hubei Province, Huazhong Agricultural University, Wuhan, 430070, Hubei, ChinaSearch for more papers by this author, M. D. Wu†Corresponding author: M. D. Wu; E-mail: E-mail Address: mingde@mail.hzau.edu.cnhttp://orcid.org/0000-0001-8014-5688The State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, 430070, Hubei, China; and The Key Laboratory of Plant Pathology of Hubei Province, Huazhong Agricultural University, Wuhan, 430070, Hubei, ChinaSearch for more papers by this author, and G. Q. LiThe State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, 430070, Hubei, China; and The Key Laboratory of Plant Pathology of Hubei Province, Huazhong Agricultural University, Wuhan, 430070, Hubei, ChinaSearch for more papers by this authorAffiliationsAuthors and Affiliations K. Zhou1 2 Y. H. Yang1 2 M. D. Wu1 2 † G. Q. Li1 2 1The State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, 430070, Hubei, China; and 2The Key Laboratory of Plant Pathology of Hubei Province, Huazhong Agricultural University, Wuhan, 430070, Hubei, China Published Online:15 Feb 2019https://doi.org/10.1094/PDIS-06-18-1015-PDNAboutSectionsSupplemental ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmailWechat Ornamental kale (Brassica oleracea var. acephala), a biennial herbaceous cabbage, is widely grown for its ornamental leaves over the world. In May 2018, necrotic lesions on lower leaf petioles and blackleg symptoms on basal stems of flowering-stage ornamental kale were observed in Yangzhou, Jiangsu Province. The disease incidence was relatively low with approximately 5% in surveyed fields. To determine the causal agent, diseased leaf petioles were cut into pieces, surface sterilized (Zhou et al. 2019), and placed on potato dextrose agar plates at 20°C for 7 days. Four fungal isolates were obtained, and all fungal colonies formed fluffy white aerial mycelia with a yellow pigment. In addition, black-brown and globose pycnidia of 159 × 143 μm in size (74 to 370 × 74 to 333 μm, n = 50) were also observed on the fungal colonies after 10 days. On a V8 juice agar plate, pink pycnidiospore ooze formed on top of pycnidia after 17 days of cultivation. Conidia were cylindrical, hyaline with the size of 5.5 × 2.3 μm (5 to 7.5 × 1.7 to 2.5 μm, n = 100). The cultural and morphological characteristics of the isolates matched the description for Leptosphaeria biglobosa rather than L. maculans, because the later produces no yellow pigment (Williams and Fitt 1999). For molecular identification, genomic DNA of all four isolates was extracted using the cetyltrimethylammonium bromide method and then, together with DNA samples of L. maculans isolate UK-1 and L. biglobosa isolate B2003, used for polymerase chain reaction assay with the species-specific primers LbigF, LmacF, and LmacR (Liu et al. 2006), respectively. In addition, the sequences coding for actin, β-tubulin, and the internal transcribed spacer (ITS) region of ribosomal DNA (Vincenot et al. 2008) were also cloned and used for further identification of isolate NY8-1-2. Because only a 444-bp DNA band was detected in all four isolates, they should belong to L. biglobosa rather than L. maculans, as the latter generates a 331-bp DNA band. Sequences of ITS (496 bp, GenBank accession no. MH472567), actin (900 bp, MH475334), and β-tubulin (948 bp, MH475335) for isolate NY8-1-2 were 100% identical to those of L. biglobosa strains HCLB-1 (ITS, KC880981.1), 2379-4 (actin, AY748949.1), and B3.6 (β-tubulin, AY748995.1) in GenBank, respectively. Cotyledons of six ornamental kale cultivars (Jingyu No. 1, Jingyu No. 2, Jingguanbai No. 1, Jingguanhong No. 7, Jinglianhong No. 3, and Fenhong No. 1), an oilseed rape cultivar (Zhongshuang No. 9), and a cabbage cultivar (Jingfeng No. 1) were used to test the pathogenicity. Pycnidiospore suspension (10 μl, 1 × 107 conidia/ml) of isolate NY8-1-2 was wound inoculated on cotyledons of 14-day-old seedlings, with 12 cotyledons (= 24 wounded sites) per isolate, and 12 wounded cotyledons inoculated with water served as a control group. Treated seedlings were incubated at 20°C and 100% relative humidity under 12 h of light/12 h of dark for 7 days. Whereas the control group remained healthy, necrotic lesions around the inoculated sites were observed for all cultivars of ornamental kale, oilseed rape, and cabbage. The fungus reisolated from the diseased cotyledons resembled colony morphology to the original isolate. Therefore, L. biglobosa was determined to be the causal agent of blackleg on ornamental kale in China. Although L. biglobosa can cause blackleg on cabbage (B. oleracea) in Mexico (Dilmaghani et al. 2010), to our knowledge this is the first report of L. biglobosa causing blackleg on B. oleracea var. acephala in China.References:Dilmaghani, A., et al. 2010. Plant Dis. 94:791. https://doi.org/10.1094/PDIS-94-6-0791C Link, ISI, Google ScholarLiu, S. Y., et al. 2006. Plant Pathol. 55:401. https://doi.org/10.1111/j.1365-3059.2006.01354.x Crossref, ISI, Google ScholarVincenot, L., et al. 2008. Phytopathology 98:321. https://doi.org/10.1094/PHYTO-98-3-0321 Link, ISI, Google ScholarWilliams, R. H., and Fitt, B. D. L. 1999. Plant Pathol. 48:161. https://doi.org/10.1046/j.1365-3059.1999.00333.x Crossref, ISI, Google ScholarZhou, K., et al. 2019. Plant Dis. 103:160. https://doi.org/10.1094/PDIS-06-18-0990-PDN Link, ISI, Google ScholarFunding: This research was funded by China Agriculture Research System (grant number: CARS-12) and the National Natural Science Foundation of China (grant number 31401690).DetailsFiguresLiterature CitedRelated Vol. 103, No. 4 April 2019SubscribeISSN:0191-2917e-ISSN:1943-7692 DownloadCaptionGray mold on kiwifruit leaves caused by Botrytis cinerea (courtesy Guoshu Gong and Qinjun Tao); sunflower rust on bracts (courtesy Sam Markell); cucumber plant with mosaic symptoms caused by papaya ringspot virus (courtesy Roger Jones). Metrics Article History Issue Date: 10 Apr 2019Published: 15 Feb 2019First Look: 30 Oct 2018Accepted: 28 Oct 2018 Pages: 770-770 Information© 2019 The American Phytopathological SocietyFundingChina Agriculture Research SystemGrant/Award Number: CARS-12National Natural Science Foundation of ChinaGrant/Award Number: 31401690Cited byViral cross-class transmission results in disease of a phytopathogenic fungus31 August 2022 | The ISME Journal, Vol. 16, No. 12First Report of Leptosphaeria biglobosa ‘brassicae’ Causing Blackleg on Brassica juncea var. multisecta in ChinaYuexuan Long, Mingxue Shang, Yue Deng, Chuan Yu, Mingde Wu, and Guoqing Li15 November 2021 | Plant Disease, Vol. 105, No. 11First Report of Leptosphaeria biglobosa ‘canadensis’ Causing Blackleg on Oilseed Rape (Brassica napus) in ChinaTao Luo, Guoqing Li, and Long Yang11 November 2021 | Plant Disease, Vol. 105, No. 11Status and advances in mining for blackleg (Leptosphaeria maculans) quantitative resistance (QR) in oilseed rape (Brassica napus)9 June 2021 | Theoretical and Applied Genetics, Vol. 134, No. 10