First Report of <i>Colletotrichum aenigma</i> Causing Apple Glomerella Leaf Spot on the Granny Smith Cultivar in China

HomePlant DiseaseVol. 105, No. 5First Report of Colletotrichum aenigma Causing Apple Glomerella Leaf Spot on the Granny Smith Cultivar in China PreviousNext DISEASE NOTES OPENOpen Access licenseFirst ChinaZhaohui Zhang, Mingjie Yan, Wenwen Li, Yunzhong Guo, and Xiaofei LiangZhaohui ZhangState Key Laboratory Crop Stress Biology Arid Areas College Plant Protection, Northwest A&F University, Yangling, ChinaSearch for more papers by this author, YanState LiState Guo†Corresponding authors: Y. Z. Guo; E-mail Address: [email protected] andd X. F. Liang; [email protected] Liang†Corresponding [email protected]://orcid.org/0000-0002-3279-5894State author AffiliationsAuthors Affiliations Zhaohui Zhang Yan Li Guo † Liang State Published Online:9 Apr 2021https://doi.org/10.1094/PDIS-10-20-2298-PDNAboutSectionsView articlePDFPDF PlusSupplemental ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmailWechat View articleGlomerella leaf spot (GLS) is a devastating fungal disease causing premature defoliation apple (Malus domestica). It was first reported 1970s since then has been North America, South Asia. GLS caused fungi, pathogens are genetically diverse, encompassing at least nine species belonging three complexes (Velho et al. 2018). In August 2018, with sudden necrosis symptom, typical symptom appearance, occurred ‘Granny Smith’ orchard Wugong county, China; over 70% tree leaves bore brown necrotic lesions. Small tissues (3 4 mm2) cut from lesion margins were surface sterilized 30 s 3% NaClO 75% ethanol, followed rinsing times sterile water before transferring onto potato dextrose agar (PDA) plates (25 ± 2°C). Seven isolates obtained, all producing round cottony colonies PDA, being white pale upper side dark green reverse side. Conidia single-celled, cylindrical, transparent (17.33 1.29 × 5.11 0.77 μm, n = 50). Appressoria thick-walled, brown, oval or irregular shaped, sometimes lobed (9.07 0.88 6.66 0.33 The morphological cultural characteristics matched descriptions (Weir 2012). To confirm identity, genomic DNA isolated two representative (QSG1 QSY1), internal transcribed spacer (ITS), actin (ACT), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), beta-tubulin (TUB2), manganese-superoxide dismutase (SOD2), chitin synthase (CHS), calmodulin (CAL) regions amplified PCR using primers sequences deposited GenBank (accession nos. MT872061, MT873580, MT873581, MT888183, MT888185, MT888187, MT888189 QSG1; MT834933, MT835166, MT873579, MT888182, MT888184, MT888186, MT888188 QSY1). BLASTn search against nr database showed that ITS strains high nucleotide identity (over 99%) derived gloeosporioides complex (CGSC). Further concatenated phylogenetic analysis CGSC 2012) placed QSG1 QSY1 clade C. aenigma. fulfill Koch’s postulates, field pathogenicity test performed. experiment performed an located Yangling September 2020, daily average temperature ranging between 15 20°C. Healthy alcohol inoculated conidial suspension (106 conidia/ml) cotton swabs. For each isolate, 10 inoculations Inoculation distilled served as negative control. Inoculated covered plastic bags maintain humidity, removed 48 h postinoculation. Conidium-inoculated started exhibit GLS-resembling lesions 5 days postinoculation (dpi) onward. extent, however, varied among leaves, blurry, small-sized blight entire leaf. contrast conidium inoculations, water-inoculated remained asymptomatic until 14 dpi. Reisolated fungi symptomatic identical appearance. Taken together, report China. This information should provide important guideline developing control practices GLS.The author(s) declare no conflict interest.References:Velho, A. C., 2018. Trop. Pathol. 44:197. https://doi.org/10.1007/s40858-018-0261-x Crossref, ISI, Google ScholarWeir, B. S., 2012. Stud. Mycol. 73:115. https://doi.org/10.3114/sim0011 ScholarThe interest.Funding: work supported National Research Development Program (2016YFD0201132).DetailsFiguresLiterature CitedRelated Vol. May 2021SubscribeISSN:0191-2917e-ISSN:1943-7692 DownloadCaptionSymptoms bacterial Cucurbita pepo after spray inoculation (L. al.). Photo credit: J. Li. Symptoms Fusarium wilt cyclamen (V. Guarnaccia M. L. Gullino. Metrics Downloaded 594 Article History Issue Date: 26 Aug 2021Published: 9 2021First Look: Jan 2021Accepted: 28 Dec 2020 Page: 1563 Information© 2021 American Phytopathological SocietyFundingNational ChinaGrant/Award Number: 2016YFD0201132KeywordsGlomerellaappleColletotrichumThe interest.Cited ByColletotrichum complexes: geographic distribution, host range conservation status29 | Fungal Diversity, 110, 1