First Report of Charcoal Rot on Tobacco Caused by Macrophomina phaseolina in Hunan Province, China

HomePlant DiseaseAhead of PrintFirst Report of Charcoal Rot on Tobacco Caused by Macrophomina phaseolina in Hunan Province, China PreviousNext DISEASE NOTE OPENOpen Access licenseFirst Report of Charcoal Rot on Tobacco Caused by Macrophomina phaseolina in Hunan Province, ChinaMingyan Geng, Kai Teng, Jin Chao, Junwu Zhu, Jing Wang, and Xianjie CaiMingyan Genghttps://orcid.org/0009-0004-4264-2025Tobacco Research Institute of Chinese Academy of Agricultural Sciences, Qingdao, China, Kai TengXiangxi Branch of Hunan Tobacco Company, Jishou, China, Jin ChaoXiangxi Branch of Hunan Tobacco Company, Jishou, China, Junwu ZhuMaterial Purchasing Center of Shanghai Tobacco Group Co., Ltd., Shanghai, China, Jing Wang†Corresponding authors: J. Wang; E-mail Address: [email protected], and X. J. Cai; E-mail Address: [email protected]Tobacco Research Institute of Chinese Academy of Agricultural Sciences, Qingdao, China, and Xianjie Cai†Corresponding authors: J. Wang; E-mail Address: [email protected], and X. J. Cai; E-mail Address: [email protected]Material Purchasing Center of Shanghai Tobacco Group Co., Ltd., Shanghai, ChinaAffiliationsAuthors and Affiliations Mingyan Geng1 Kai Teng2 Jin Chao2 Junwu Zhu3 Jing Wang1 † Xianjie Cai3 † 1Tobacco Research Institute of Chinese Academy of Agricultural Sciences, Qingdao, China 2Xiangxi Branch of Hunan Tobacco Company, Jishou, China 3Material Purchasing Center of Shanghai Tobacco Group Co., Ltd., Shanghai, China Published Online:3 Apr 2024https://doi.org/10.1094/PDIS-12-23-2572-PDNAboutSectionsView articlePDFSupplemental ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmailWechat View articleFlue-cured tobacco (Nicotiana tabacum L.) is a significant cash crop globally. In August 2022, necrotic lesions on stems associated with root rot and wilting were observed on flue-cured tobacco (cv. Yunyan 87) in fields located in the Banxin village (27.95°N, 109.60°E) of Fenghuang County, Xiangxi Autonomous Prefecture, Hunan Province, China. The affected and damaged area of tobacco was approximately 10 ha, with a disease incidence of 60%. Lots of small black speckling within the lower stem of the affected plant were observed, and the vascular tissue changed to black, dry rot and looked like charcoal breezes. Small pieces were cut from healthy and diseased tissues, surface sterilized with 5% NaClO for 3 min and 75% ethanol for 1 min, rinsed with sterile distilled water, air-dried, and incubated on oat medium at 28°C for 5 days. These isolates grew fast and produced typical black microsclerotia. The morphological study showed septate hyphae and microsclerotia. The microsclerotia were black, regularly round, and 42.5 to 92.9 μm in diameter. These morphological features were consistent with Macrophomina phaseolina (Smith et al. 1999). The internal transcribed spacer (ITS) rDNA and translation elongation factor 1-α (TEF1-α) genes of three representative isolates were amplified and sequenced using the primers ITS1/ITS4 and EF1-728F/EF2R (Machado et al. 2019). Our resulting sequences (GenBank accession nos. OR435093, OR435101, and OR435102 for ITS; OR891780, OR891781, and OR891782 for TEF1-α) showed 99 to 100% similarity with M. phaseolina by NCBI BLAST. Phylogenetic analysis was conducted using MEGA-X software with the neighbor-joining method. The combined sequences grouped isolates with M. phaseolina with 100% bootstrap support. The strain XF22 was sent to the China General Microbiological Culture Collection Center (CGMCC 3.25349). Pathogenicity tests were conducted by inoculating potted plants (six plants per isolate, three times) from 45-day-old tobacco seedlings cultivar Yunyan 87. Stems were randomly gently scratched with sterile needles, and 5-mm agar discs with mycelium of the pathogen were attached to the surface of each wound, with a sterilized agar disc as a control. Inoculated seedlings were incubated in growth chambers at 26°C and 60% relative humidity with a 12-h photoperiod. After 10 days, brown or black lesions on the inoculated plants were dotted with numerous black, hard microsclerotia similar to those naturally occurring on the diseased plants, whereas the control plants were symptomless. The same pathogen was reisolated consistently, fulfilling Koch's postulates. Based on morphological, molecular, and pathogenicity test results, these isolates were identified as M. phaseolina. Charcoal rot of tobacco caused by M. phaseolina was previously found in Guangxi in 1989 (Zhu et al. 2002), while this is the first report of M. phaseolina causing charcoal rot on flue-cured tobacco in Hunan, China. We speculate that the planting area is influenced by the preceding crop sesame. The soil carries M. phaseolina, which can cause stem rot of sesame, leading to the occurrence of tobacco charcoal rot. Our results indicated that charcoal rot caused by M. phaseolina is a new threat to flue-cured tobacco production, and flue-cured tobacco might be acting as a reservoir and spreading this pathogen to other economically important crops in China.The author(s) declare no conflict of interest.References:Machado, A. R., et al. 2019. Eur. J. Plant Pathol. 153:89. https://doi.org/10.1007/s10658-018-1545-1Crossref, ISI, Google ScholarSmith, G. S., et al. 1999. Page 29 in: Compendium of Soybean Diseases. American Phytopathological Society, St. Paul, MN.Google ScholarZhu, C. X., et al. 2002. Page 97 in: Tobacco Disease of China. China Agriculture Press, Beijing, China.Google ScholarM. Geng and K. Teng contributed equally to this work.Funding: This work was in part supported by the CNTC project, funded by the Shanghai Tobacco Group (40736), and the Agricultural Science and Technology Innovation Program of Chinese Academy of Agricultural Sciences (ASTIP-TRIC04).The author(s) declare no conflict of interest.DetailsFiguresLiterature CitedRelated Just PublishedSubscribeISSN:0191-2917e-ISSN:1943-7692 Metrics Article History Published: 3 Apr 2024First Look: 21 Feb 2024Accepted: 12 Feb 2024 Information© 2024 The American Phytopathological SocietyFundingShanghai Tobacco GroupGrant/Award Number: 40736Agricultural Science and Technology Innovation ProgramGrant/Award Number: ASTIP-TRIC04KeywordsMacrophomina phaseolinapathogen detectiontobaccoThe author(s) declare no conflict of interest.PDF download