title: DNA barcoding and isolation of vertically transmitted ascomycetes in sorghum from Burkina Faso: Epicoccum sorghinum is dominant in seedlings and appears as a common root pathogen.
abstract: Molecular identification of fungal taxa commonly transmitted through seeds of sorghum in Western Africa is lacking. In the present study, farm-saved seeds, collected from four villages in Northern Burkina Faso, were surface sterilized and the distribution of fungal DNA in seeds and seven-day-old seedlings was analyzed by 18S ribosomal DNA (rDNA) amplicon sequencing. More than 99% of the fungal rDNA was found to originate from ascomycetes. The distribution of ascomycetes at species level was subsequently analyzed by barcoding of ITS2 rDNA. Eighteen Operational Taxonomic Units (OTUs) were identified from seedlings, compared to 29 OTUs from seeds. The top-eight most abundant ascomycete OTUs from seedlings were annotated as: Epicoccum sorghinum, Fusarium thapsinum, four different Curvularia spp., Exserohilum rostratum and Alternaria longissima. These OTUs were also present in amplicons from seed samples collected in Central Burkina Faso confirming a common occurrence. E. sorghinum was highly predominant in seedlings both measured by DNA analysis and by isolation. The dominance of E. sorghinum was particularly strong in roots from poorly growing seedlings. Pathogenicity of E. sorghinum isolates was compared to F. thapsinum by inoculation to seeds in vitro. Both fungal species caused significant inhibition of seedling growth (P<0.001) and Koch's postulates were fulfilled. Extensive, dark necrosis in roots was a typical symptom of E. sorghinum, whereas wilting of leaves was caused primarily by F. thapsinum. This study provides the first molecular approach to characterize the seedling mycoflora of sorghum in Western Africa and suggests E. sorghinum as a common root pathogen.
authors.affiliation: Institute of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, Hoejbakkegaard Allé 13, DK-2630 Taastrup, Denmark.
authors.forename: Michaela S
authors.initials: MS
authors.lastname: Stokholm
authors.affiliation: Division of Plant Diagnostics, Danish Veterinary and Food Administration, Ministry of Food, Agriculture and Fisheries, Soendervang 4, DK-4100 Ringsted, Denmark.
authors.forename: Ednar G
authors.initials: EG
authors.lastname: Wulff
authors.affiliation: Kamboinsé Research Station, INERA (Institut de l'Environnement et de Recherches Agricoles), 01 P.O. Box 476 Ouagadougou 01, Burkina Faso.
authors.forename: Elisabeth P
authors.initials: EP
authors.lastname: Zida
authors.affiliation: Kamboinsé Research Station, INERA (Institut de l'Environnement et de Recherches Agricoles), 01 P.O. Box 476 Ouagadougou 01, Burkina Faso.
authors.forename: Ibié G
authors.initials: IG
authors.lastname: Thio
authors.affiliation: Kamboinsé Research Station, INERA (Institut de l'Environnement et de Recherches Agricoles), 01 P.O. Box 476 Ouagadougou 01, Burkina Faso.
authors.forename: James B
authors.initials: JB
authors.lastname: Néya
authors.affiliation: Kamboinsé Research Station, INERA (Institut de l'Environnement et de Recherches Agricoles), 01 P.O. Box 476 Ouagadougou 01, Burkina Faso.
authors.forename: Romain W
authors.initials: RW
authors.lastname: Soalla
authors.affiliation: Institute of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, Hoejbakkegaard Allé 13, DK-2630 Taastrup, Denmark.
authors.forename: Sylwia E
authors.initials: SE
authors.lastname: Głazowska
authors.affiliation: Institute of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, Hoejbakkegaard Allé 13, DK-2630 Taastrup, Denmark.
authors.forename: Marianne
authors.initials: M
authors.lastname: Andresen
authors.affiliation: Department of Agroecology, Science and Technology, Aarhus University, Forsoegsvej 1, DK-4200 Slagelse, Denmark.
authors.forename: Henrik B
authors.initials: HB
authors.lastname: Topbjerg
authors.affiliation: Department of Agroecology, Science and Technology, Aarhus University, Forsoegsvej 1, DK-4200 Slagelse, Denmark.
authors.forename: Birte
authors.initials: B
authors.lastname: Boelt
authors.affiliation: Institute of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, Hoejbakkegaard Allé 13, DK-2630 Taastrup, Denmark. Electronic address: osl@plen.ku.dk.
authors.forename: Ole S
authors.initials: OS
authors.lastname: Lund
mesh_terms: D001203:Ascomycota / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D002050:Burkina Faso; D016000:Cluster Analysis; D058893:DNA Barcoding, Taxonomic; D004271:DNA, Fungal / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D021903:DNA, Ribosomal Spacer / Q000737:chemistry / Q000235:genetics; D014644:Genetic Variation; D010802:Phylogeny; D010935:Plant Diseases / Q000382:microbiology; D018517:Plant Roots / Q000382:microbiology; D012337:RNA, Ribosomal, 18S / Q000235:genetics; D036226:Seedlings / Q000382:microbiology; D017422:Sequence Analysis, DNA; D045868:Sorghum / Q000382:microbiology*
chemical_list: D004271:DNA, Fungal; D004275:DNA, Ribosomal; D021903:DNA, Ribosomal Spacer; D012337:RNA, Ribosomal, 18S
keywords: Curvularia lunata; Fusarium moniliforme; Mycobiome; Pathogenicity; Phoma sorghina; Pyrosequencing