First Report on Colletotrichum siamense Causing Anthracnose of Castor Bean in Zhanjiang, China

HomePlant DiseaseVol. 105, No. 10First Report on Colletotrichum siamense Causing Anthracnose of Castor Bean in Zhanjiang, China PreviousNext DISEASE NOTE OPENOpen Access licenseFirst Report on Colletotrichum siamense Causing Anthracnose of Castor Bean in Zhanjiang, ChinaJ. R. Tang, Y. L. Liu, X. G. Yin, and J. N. LuJ. R. TangGuangdong Ocean University, Zhanjiang, Guangdong 524088, China, Y. L. Liu†Corresponding author: Y. L. Liu; E-mail Address: mushwoman@126.comhttps://orcid.org/0000-0002-4145-9278Guangdong Ocean University, Zhanjiang, Guangdong 524088, China, X. G. YinGuangdong Ocean University, Zhanjiang, Guangdong 524088, China, and J. N. LuGuangdong Ocean University, Zhanjiang, Guangdong 524088, China AffiliationsAuthors and Affiliations J. R. Tang Y. L. Liu † X. G. Yin J. N. Lu Guangdong Ocean University, Zhanjiang, Guangdong 524088, China Published Online:26 Oct 2021https://doi.org/10.1094/PDIS-01-21-0119-PDNAboutSectionsView articlePDFSupplemental ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmailWechat View articleCastor bean (Ricinus communis L.) is an important oil crop. Anthracnose lesions were observed on leaves of castor bean at the stage of budding and fruiting in a field (21°17′51″N, 110°18′16″E), Zhanjiang, Guangdong Province, China, in August 2019. The incidence rate was approximately 40% (n = 600 investigated plants). Early symptoms were yellow spots appearing from the edge or the tip of the leaves. Later, the spots gradually expanded and became dark brown, which coalesced into larger irregular or circular lesions. Seven diseased leaves were collected from seven plants. Margins of the diseased tissue were cut into 2 × 2-mm pieces. The surfaces were disinfested with 75% ethanol for 30 s and 2% sodium hypochlorite for 60 s. Thereafter, the samples were rinsed three times in sterile water, placed on potato dextrose agar (PDA), and incubated at 28°C. Pure cultures were obtained by transferring hyphal tips to new PDA plates. A single-spore isolate (RLC-1) was used for further study. The colony of isolate RLC-1 on PDA was white to gray in color with cottony mycelia in 6 days at 28°C. Conidia were one-celled, hyaline, cylindrical, clavate, obtuse at both ends, and measured 14.2 to 18.5 × 3.8 to 5.5 µm (n = 50). Appressoria were oval to irregular in shape, dark brown, and were 7.3 to 10.5 × 5.7 to 6.5 µm (n = 20). Morphological characteristics of isolate RLC-1 were consistent with the description of Colletotrichum siamense (Prihastuti et al. 2009; Sharma et al. 2013). DNA of the isolate RLC-1 was extracted for PCR sequencing using primers for the rDNA ITS (ITS1/ITS4), GAPDH (GDF1/GDR1), and ACT (ACT-512F/ACT-783R) (Weir et al. 2012). Analysis of the ITS (accession no. MN880199), GAPDH (MN884048), and ACT (MN891766) sequences revealed 99 to 100% identity with the corresponding ITS (JX010250), GAPDH (KX578786), and ACT (JX009541) sequences of C. siamense in GenBank. A phylogenetic tree was generated on the basis of the concatenated data from sequences of ITS, GAPDH, and ACT that clustered the isolate RLC-1 with C. siamense with the type strain ICMP 19118. Morphological characteristics and phylogenetic analysis identified the isolate RLC-1 associated with anthracnose of castor bean as C. siamense. A pathogenicity test was performed in a greenhouse at 24 to 30°C with 80% relative humidity. Twenty healthy plants of Zi Bi No. 5 castor bean (2 months old) were grown in pots with one plant in each pot. Inoculation was conducted on leaves with mycelial plugs of RLC-1 or agar plugs (as a control). Three plugs were considered for each leaflet. Ten plants were used in each treatment (five for wounded inoculation and five for unwounded inoculation). Anthracnose lesions as earlier were observed on the leaves after 2 weeks, whereas the control plants remained healthy. The pathogen reisolated from all inoculated leaves was identical to the isolate RLC-1 by morphology and ITS analysis, but it was unsuccessful from control plants. C. siamense causes anthracnose on various plant hosts, including mango in Colombia (Pardo-De la Hoz et al. 2016) and Rosa chinensis in China (Feng et al. 2019) but not previously including castor bean. To the best of our knowledge, this study is the first to report C. siamense causing anthracnose on castor bean. Thus, this work provides a basis for focusing on the management of the disease in future.The author(s) declare no conflict of interest.References:Feng, F. S., et al. 2019. Plant Dis. 103:1422. https://doi.org/10.1094/PDIS-11-18-1966-PDN Link, ISI, Google ScholarPardo-De la Hoz, C. J., et al. 2016. Plant Pathol. 65:227. https://doi.org/10.1111/ppa.12410 Crossref, ISI, Google ScholarPrihastuti, H., et al. 2009. Fungal Divers. 39:89. ISI, Google ScholarSharma, G., et al. 2013. Fungal Divers. 61:117. https://doi.org/10.1007/s13225-013-0247-4 Crossref, ISI, Google ScholarWeir, B. S., et al. 2012. Stud. Mycol. 73:115. https://doi.org/10.3114/sim0011 Crossref, ISI, Google ScholarThe author(s) declare no conflict of interest.Funding: This research was supported by Science and Technology Program of Guangdong Province (2016A020208015) and Postgraduate Education Innovation Program of Guangdong Ocean University (202034).DetailsFiguresLiterature CitedRelated Vol. 105, No. 10 October 2021SubscribeISSN:0191-2917e-ISSN:1943-7692 DownloadCaptionPycnidia of Leptosphaeria biglobosa formed on a necrotic tissue of a blighted leaf petiole of Brassica rapa subsp. pekinensis (C. Yu et al.). Photo credit: C. Yu. Panicle blast of rice from a site in sub-Saharan Africa (S. K. Mutiga et al.). Photo credit: V. Were. Symptoms of bud soft rot on agave caused by Pantoea dispersa (F. Palemón-Alberto et al.). Photo credit: S. Ortega-Acosta. Metrics Downloaded 611 times Article History Issue Date: 28 Dec 2021Published: 26 Oct 2021First Look: 26 Apr 2021Accepted: 22 Apr 2021 Page: 3293 Information© 2021 The American Phytopathological SocietyFundingScience and Technology Program of Guangdong ProvinceGrant/Award Number: 2016A020208015Postgraduate Education Innovation Program of Guangdong Ocean UniversityGrant/Award Number: 202034KeywordsRicinus communisColletotrichum siamenseanthracnoseThe author(s) declare no conflict of interest.PDF download