First Report of Green Mold on Leaves of Phaseolus vulgaris Caused by Cladosporium tenuissimum in Liaoning, China

HomePlant DiseaseAhead of PrintFirst Report of Green Mold on Leaves of Phaseolus vulgaris Caused by Cladosporium tenuissimum in Liaoning, China PreviousNext DISEASE NOTE OPENOpen Access licenseFirst Report of Green Mold on Leaves of Phaseolus vulgaris Caused by Cladosporium tenuissimum in Liaoning, ChinaX. M. Gao, X. H. Yang, Y. Li, M. Yu, J. Ao, X. H. Liu, Y. L. Sun, L. Q. Song, F. Chen, and L. L. GuoX. M. Gaohttps://orcid.org/0009-0008-2545-4400Microbial Research Institute of Liaoning Province, Chaoyang 122000, China, X. H. YangJiamusi Branch of Heilongjiang Academy of Agricultural Sciences, Jiamusi 154000, China, Y. LiMicrobial Research Institute of Liaoning Province, Chaoyang 122000, China, M. YuMicrobial Research Institute of Liaoning Province, Chaoyang 122000, China, J. AoMicrobial Research Institute of Liaoning Province, Chaoyang 122000, China, X. H. LiuMicrobial Research Institute of Liaoning Province, Chaoyang 122000, China, Y. L. SunMicrobial Research Institute of Liaoning Province, Chaoyang 122000, China, L. Q. SongMicrobial Research Institute of Liaoning Province, Chaoyang 122000, China, F. ChenMicrobial Research Institute of Liaoning Province, Chaoyang 122000, China, and L. L. Guo†Corresponding author: L. L. Guo; E-mail Address: [email protected]Microbial Research Institute of Liaoning Province, Chaoyang 122000, ChinaAffiliationsAuthors and Affiliations X. M. Gao1 X. H. Yang2 Y. Li1 M. Yu1 J. Ao1 X. H. Liu1 Y. L. Sun1 L. Q. Song1 F. Chen1 L. L. Guo1 † 1Microbial Research Institute of Liaoning Province, Chaoyang 122000, China 2Jiamusi Branch of Heilongjiang Academy of Agricultural Sciences, Jiamusi 154000, China Published Online:30 Apr 2024https://doi.org/10.1094/PDIS-09-23-1969-PDNAboutSectionsView articlePDFSupplemental ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmailWechat View articlePhaseolus vulgaris L. is a widely cultivated vegetable throughout the world. From spring 2019 to 2022, green mold symptoms were observed on leaves of P. vulgaris in a greenhouse in Liaoning, China, with a disease incidence of 8 to 75% in plants and 6 to 23% in leaves. Symptoms appeared as chlorotic lesions covered with dark green mold. The infections started at the apex or margin of the leaves and then spread inward with a characteristic "V" shape. Lesions exhibited curly morphology. Fifteen leaf samples with typical symptoms were collected from five different greenhouses. A total of 75 (five replicates for each sample) leaf tissues (0.5 × 0.5 cm) were cut from the boundary between diseased and healthy parts. These samples were surface sterilized in 0.5% NaClO for 5 min, rinsed three times in sterile distilled water, and subsequently incubated at 28°C on potato dextrose agar supplemented with streptomycin (50 μg/ml). Numerous morphologically uniform colonies had been purified, with no other fungi observed. Afterwards, the strains were subcultured on malt extract agar (MEA). Colonies on MEA reached 70 to 80 mm diameter after 14 days, which were smoke-gray to pale olivaceous gray, woolly, and sometimes radially wrinkled. Mycelia were pale olivaceous gray, with hyphae measuring 1 to 5 μm wide (n = 20). Conidiophores were solitary or in groups of 2 to 5 and measured 50 to 280 (−350) × 2.5 to 4 μm (n = 20), with 2 to 7 septa. Conidiogenous cells exhibited a cylindrical-oblong morphology and measured 10 to 44 × 5 μm (n = 20), with 0 to 2 septa, and the loci frequently thickened. Conidia were catenate in densely branched chains, ellipsoid to obovoid, smooth, and measured 2.5 to 5 × 2 to 3 μm (n = 50), with 0 to 4 septa. The morphological characteristics were similar to Cladosporium tenuissimum (Zhang 2003). The representative isolate KZ-19 was selected for molecular identification. The rDNA internal transcribed spacer (ITS), translation elongation factor 1-α (EF-1α), and actin (ACT) genes were amplified and sequenced, and the resulting sequence data were submitted to GenBank (ITS, OQ931048; EF-1α, OQ954495; ACT, OQ954496). The BLAST results exhibited a 99 to 100% similarity with the sequences of the C. tenuissimum type strain CBS 125995 (ITS, HM148197; EF-1α, HM148442; ACT, HM148687). Furthermore, a multilocus phylogenetic tree was constructed using the PhyloSuite (v 1.2.2) software, which revealed that the strains were most closely related to C. tenuissimum (Zhang et al. 2020). Based on both morphological and molecular characteristics, KZ-19 was finally identified as C. tenuissimum (Bensch et al. 2012). Pathogenicity testing was performed on healthy 1-month-old P. vulgaris plants by inoculating the spore suspension (1 × 106 conidia/ml) of KZ-19 onto leaf surfaces, whereas control plants were inoculated with sterile water, and five pots were used for each treatment. The test was performed under field conditions at 16 to 28°C and 24 to 56% relative humidity. Chlorotic lesions became evident within 2 days after inoculation, followed by the appearance of green mold on leaves after 7 days. No symptoms were observed in the control group. To fulfill Koch's postulates, the pathogen was reisolated from three inoculated leaves. The morphological identification of reisolated pathogens was similar to that of originally isolated pathogens. No infection was observed in the noninoculated controls. To the best of our knowledge, this is the first report of C. tenuissimum causing green mold on P. vulgaris. As a ubiquitous saprobic hyphomycete, C. tenuissimum has been implicated in leaf mold in Punica granatum and Trifolium repens, larch bud blight, and strawberry blossom blight in previous years (He and Zhao 1987; Nam et al. 2015; Zhang 2003; Zheng et al. 2010), presenting a potential threat to numerous crops. Therefore, an investigation of its distribution and pathogenic potential is essential in addition to the development of effective disease management strategies.The author(s) declare no conflict of interest.References:Bensch, K., et al. 2012. Stud. Mycol. 72:1. https://doi.org/10.3114/sim0003Crossref, ISI, Google ScholarHe, P. X., and Zhao, L. S. 1987. J. Jilin For. Sci. Tech. 66:24.Google ScholarNam, M. H., et al. 2015. Mycobiology 43:354.Crossref, ISI, Google ScholarZhang, D., et al. 2020. Mol. Eco. Resour. 20:348. https://doi.org/10.1111/1755-0998.13096Crossref, ISI, Google ScholarZhang, T. Y. 2003. Chinese Flora Fungorum Sinicorum. In: Alternaria. vol. 16. Science Press, Beijing, China.Google ScholarZheng, X. H., et al. 2010. Plant Protect. 36:131.Google ScholarFunding: Funding was provided by Liaoning Leading Talent in Science and Technology (no. XLYC2002048), Key Research and Development Projects of Heilongjiang Province (no. GA22B014), Heilongjiang Provincial Scientific Research Business Fee Project (no. CZKYF2023-1-B005), and Natural Science Foundation of Liaoning Province (no. 2022-MS-064).The author(s) declare no conflict of interest.DetailsFiguresLiterature CitedRelated Just PublishedSubscribeISSN:0191-2917e-ISSN:1943-7692 Metrics Article History Published: 30 Apr 2024First Look: 29 Feb 2024Accepted: 23 Feb 2024 Information© 2024 The American Phytopathological SocietyFundingLiaoning Leading Talent in Science and TechnologyGrant/Award Number: XLYC2002048Key Research and Development Projects of Heilongjiang ProvinceGrant/Award Number: GA22B014Heilongjiang Provincial Scientific Research Business Fee ProjectGrant/Award Number: CZKYF2023-1-B005Natural Science Foundation of Liaoning ProvinceGrant/Award Number: 2022-MS-064KeywordsCladosporium tenuissimumgreen moldkidney beanThe author(s) declare no conflict of interest.PDF download