Cercospora zeina is the causal agent of grey leaf spot disease of maize in southern Africa

• Published in: European journal of plant pathology Vol. 124; no. 4; pp. 577 - 583
• Main Authors: Meisel, Barbara, Korsman, Jeanne, Kloppers, Frederik J., Berger, Dave K.
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.08.2009; Springer; Springer Nature B.V
• Subjects: Agriculture; Biological and medical sciences; Biomedical and Life Sciences; Cercospora; Cercospora zeae-maydis; Conidia; Corn; Crop diseases; Deoxyribonucleic acid; DNA; DNA fragmentation; DNA primers; Ecology; Fundamental and applied biological sciences. Psychology; Fungal plant pathogens; fungi; genes; grey leaf spot disease; histones; internal transcribed spacers; Leaves; Lesions; Life Sciences; pathogens; Phytopathology. Animal pests. Plant and forest protection; Plant Pathology; Plant Sciences; plantations; polymerase chain reaction; rapid methods; sequence alignment; South Africa; Zambia; Zea mays; Zimbabwe; Southern Africa; Africa; South Africa; Zimbabwe; Zambia; Koch’s postulates; Diagnostic species-specific PCR assay; Grey leaf spot; Maize; Monocotyledones; Plant pathology; Zea mays; Microbiology; Plant pathogen; Species specificity; Cereal crop; Fungi; Polymerase chain reaction; Cercospora zeina; Gramineae; Angiospermae; Spermatophyta; Fungi Imperfecti; Koch's postulates; Cercospora zeae-maydis
• ISSN: 0929-1873; 1573-8469
• DOI: 10.1007/s10658-009-9443-1

The aim of our study was to identify the causal agent of grey leaf spot disease of maize in southern Africa. Single-conidial cultures were recovered from maize leaves with typical disease symptoms sampled from several fields in South Africa, Zambia and Zimbabwe. Morphology, cultural characteristics, and a PCR-based test using Cercospora zeae-maydis and C. zeina -specific primer sets identified all single-conidial cultures as C. zeina . In addition, sequence alignment of DNA fragments of the internal transcribed spacer region (ITS1, ITS2, and the 5.8S gene) and elongation factor 1-α grouped all cultures in the same clade as the C. zeina ex-type culture CBS 118820. To by-pass cultivation of the slow-growing fungus, a rapid method to isolate DNA directly from lesions was successfully applied for PCR identification of C. zeina with species-specific ITS and histone primers. Koch’s postulates were fulfilled for C. zeina by artificially inoculating maize plants in a greenhouse, re-isolating conidia emerging from lesions and verifying pathogen identity with molecular techniques. These results provide evidence that confirms the presence of C. zeina and absence of C. zeae-maydis in commercial maize plantations in southern Africa.