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First Report of Lasiodiplodia pseudotheobromae and Colletotrichum siamense Causing Cacao Pod Rot, and First Report of C. tropicale Causing Cacao Pod Rot in Puerto Rico

2019; American Phytopathological Society; Volume: 104; Issue: 2 Linguagem: Inglês

10.1094/pdis-06-19-1333-pdn

1943-7692

L. M. Serrato-Diaz, Yobana A. Mariño, Ilandra Guadalupe, Paul Bayman, Ricardo Goenaga,

Mycorrhizal Fungi and Plant Interactions

HomePlant DiseaseVol. 104, No. 2First Report of Lasiodiplodia pseudotheobromae and Colletotrichum siamense Causing Cacao Pod Rot, and First Report of C. tropicale Causing Cacao Pod Rot in Puerto Rico PreviousNext DISEASE NOTES OPENOpen Access licenseFirst Report of Lasiodiplodia pseudotheobromae and Colletotrichum siamense Causing Cacao Pod Rot, and First Report of C. tropicale Causing Cacao Pod Rot in Puerto RicoLuz M. Serrato-Diaz, Yobana A. Mariño, Ilandra Guadalupe, Paul Bayman, and Ricardo GoenagaLuz M. Serrato-Diaz†Corresponding author: L. M. Serrato-Diaz; E-mail Address: luzmiryamserratodiaz@yahoo.eshttp://orcid.org/0000-0003-4604-9160Department of Biology, University of Puerto Rico - Río Piedras, San Juan, PR, Yobana A. MariñoDepartment of Biology, University of Puerto Rico - Río Piedras, San Juan, PR, Ilandra GuadalupeDepartment of Biology, University of Puerto Rico - Río Piedras, San Juan, PR, Paul BaymanDepartment of Biology, University of Puerto Rico - Río Piedras, San Juan, PR, and Ricardo GoenagaUSDA-ARS, Tropical Agriculture Research Station, Mayagüez, PR AffiliationsAuthors and Affiliations Luz M. Serrato-Diaz1 † Yobana A. Mariño1 Ilandra Guadalupe1 Paul Bayman1 Ricardo Goenaga2 1Department of Biology, University of Puerto Rico - Río Piedras, San Juan, PR 2USDA-ARS, Tropical Agriculture Research Station, Mayagüez, PR Published Online:4 Dec 2019https://doi.org/10.1094/PDIS-06-19-1333-PDNAboutSectionsSupplemental ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmailWechat Pod rot of cacao (Theobroma cacao L.) is the most important disease of cacao fruits worldwide. During a disease survey from June to September 2017 at the USDA-ARS cacao germplasm collection in Mayagüez, Puerto Rico, cacao pod rot was observed in 14 different varieties with an incidence of 36%. Sometimes small pods were mummified, but mostly pod rot was found in mature pods. Diseased pieces (1 mm2) of 10 cacao pods per variety were surface disinfested and plated on potato dextrose agar (PDA) amended with 250 mg/liter ampicillin and 60 mg/liter streptomycin. Two isolates (I41 and I46) of Lasiodiplodia pseudotheobromae (Lps), two isolates (K21 and K51) of Colletotrichum siamense (Cos), and one isolate (K07) of Colletotrichum tropicale (Ctr) were identified using taxonomic keys (Alves et al. 2008; Weir et al. 2012) and sequencing of the internal transcribed spacer (ITS), sections of β-tubulin (BT), translation elongation factor 1 alpha (EF1-α) for Lasiodiplodia spp. and ITS rDNA, BT, chitin synthase (CHS), and glyceraldehyde 3-phosphate dehydrogenase (GAPDH) genes for Colletotrichum. Sequences were compared using the BLASTn tool with Colletotrichum and Lasiodiplodia deposited in NCBI GenBank. In PDA, colonies of Lps had initially greenish gray aerial mycelia that turned dark brown with age. Pycnidia were uniloculate and dark brown to black in color. Immature conidia were ellipsoid, apex rounded, truncate at the base, thick walled, hyaline and one-celled, becoming dark brown and two-celled with irregular longitudinal striations when mature. Conidia (n = 50) were 22.5 to 28.5 μm long by 12.5 to 14 μm wide. In PDA, colonies of Cos were grayish white with aerial mycelial growth and conidial masses, and conidia (n = 50) were 13 to 17.5 × 4 to 5.5 μm in length, one-celled, smooth walled, hyaline, cylindrical to oblong, and rounded at both ends. Appressoria were 4.5 to 5 μm in diameter and perithecia were absent. In PDA, colonies of Ctr were gray with aerial mycelial growth and conidia (n = 50) were 12.17 to 17.5 × 4 to 5 μm in length, cylindrical, hyaline, straight, and rounded at both ends. Appressoria were 7 to 10 μm in diameter and perithecia were absent. GenBank accession numbers are MK693210 and MK693211 (Lps), MK693213 and MK693214 (Cos), and MK693212 (Ctr) for ITS; MK693701 and MK693702 (Lps), MK693704 and MK693705 (Cos), and MK693703 (Ctr) for BT; MK693706 and MK693707 (Lps) for EF1-α; MK693712 and MK693713 (Cos) and MK693711 (Ctr) for CHS; and MK693709 and MK693710 (Cos) and MK693708 (Ctr) for GAPDH. Pathogenicity tests were conducted on five healthy detached and surface disinfested cacao pods per isolate. Pods were inoculated with 5-mm mycelial disks from 8-day-old pure cultures grown in PDA. Untreated controls were inoculated with PDA disks only. Fruits were kept in a humid chamber for 14 days at 25°C. The test was repeated twice. Eight days after inoculation (DAI) with Lps, all cacao pods turned dark brown, and 14 DAI gray mycelia and pycnidia of Lps were observed on cacao pods. Fourteen DAI with Cos and Ctr, all fruits turned brown, and acervuli were produced on cacao pods. Untreated controls had no symptoms of pod rot, and no fungi were isolated from tissue. Colletotrichum spp. and Lps were reisolated from their respective diseased tissues, fulfilling Koch's postulates. C. tropicale has been reported causing anthracnose on cacao pods in Japan (Shibata et al. 2015), whereas Cos has only been reported in asymptomatic cacao tissues in Australia (James et al. 2014). To our knowledge, this is the first report of Lps and Cos causing pod rot of cacao and the first report of Ctr causing pod rot of cacao in Puerto Rico.The author(s) declare no conflict of interest.References:Alves, A., et al. 2008. Fungal Divers. 28:1. ISI, Google ScholarJames, R. S., et al. 2014. Australas. Plant Dis. Notes 9:138. https://doi.org/10.1007/s13314-014-0138-x Crossref, Google ScholarShibata, A., et al. 2015. J-Stage 62:78. https://doi.org/10.11337/ktpps.2015.78 https://doi.org/10.11337/ktpps.2015.78 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.DetailsFiguresLiterature CitedRelated Vol. 104, No. 2 February 2020SubscribeISSN:0191-2917e-ISSN:1943-7692 DownloadCaptionSymptom of maize ear rot caused by Fusarium sporotrichioides (B. B. Wang et al.). Photo credit: C. X. Duan. Systemic symptoms of alfalfa mosaic virus (AMV) isolate CaM on leaves of potato (X. Z. Nie et al.). Photo credit: X. Z. Nie. Metrics Downloaded 4,711 times Article History Issue Date: 31 Jan 2020Published: 4 Dec 2019First Look: 29 Aug 2019Accepted: 28 Aug 2019 Pages: 592-592 InformationThis article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 2020.Keywordscacao pod rotLasiodiplodia pseudotheobromaeColletotrichum siamenseColletotrichum tropicaleTheobroma cacaotropical fruit diseaseThe author(s) declare no conflict of interest.Cited ByFirst Report of Anthracnose on Kadsura coccinea Caused by Colletotrichum siamense in ChinaGuihe Jiang, Aiming Jiang, Chunli Fan, Ji-Guang Wei, Liyun Ren, and Ji-Tong Luo12 August 2021 | Plant Disease, Vol. 0, No. jaPathogens Causing Anthracnose and Fruit Rots of Coffee Associated with the Coffee Berry Borer and the Entomopathogenic Fungus Beauveria bassiana in Puerto RicoLuz M. Serrato-Diaz, Yobana A. Mariño, and Paul Bayman22 July 2020 | Phytopathology®, Vol. 110, No. 9