Identification of darkly pigmented fungi associated with turfgrass roots by mycelial characteristics and RAPD-PCR

• Published in: Plant disease Vol. 80; no. 4
• Main Authors: Wetzel, H.C. III (Kansas State University, Manhattan.), Dernoeden, P.H, Millner, P.D
• Format: Journal Article
• Language: English
• Published: 1996
• Subjects: ADN; AGENT PATHOGENE; CESPED; DIAGNOSTIC; DIAGNOSTICO; DOTHIDEALES; EMPREINTE ADN; ENFERMEDADES FUNGOSAS; GAEUMANNOMYCES; GAEUMANNOMYCES GRAMINIS; GAZON; HUELLAS GENETICAS ADN; IDENTIFICACION; IDENTIFICATION; INDICE DE CRECIMIENTO; MAGNAPORTHE; MALADIE FONGIQUE; MICELIO; MYCELIUM; ORGANISMOS PATOGENOS; PCR; PHIALOPHORA; TAUX DE CROISSANCE
• ISSN: 0191-2917; 1943-7692
• DOI: 10.1094/PD-80-0359

A select group of darkly pigmented turfgrass pathogens are referred to as ectotrophic root-infecting (ERI) fungi. Identification of ERI fungi, as well as darkly pigmented saprophytes, cannot be rapidly or reliably determined by traditional methods. The objectives of this study were (i) to determine if these darkly pigmented fungi could be presumptively identified by mycelial growth rates and characteristics, and (ii) to definitively identify these fungi based on DNA products generated through random amplified polymorphic DNA (RAPD) polymerase chain reaction (PCR). Previously identified isolates of Gaeumannomyces cylindrosporus, G. graminis var. avenae, G. graminis var. graminis, G. incrustans, Magnaporthe poae, Ophiosphaerella herpotricha, O. korrae, and Phialophora graminicola were obtained. The species were separated into two groups based on their growth rate on half strength potato dextrose agar at 25 degrees C. Slower-growing species (average = 2.5; range = 1.6 to 3.4 mm per day) were G. cylindrosporus, R. graminicola, O. herpotricha, and O. korrae, whereas fast-growing species (average = 5.5; range = 3.2 to 6.6 mm per day) were G. graminis var. avenae, G. graminis var. graminis, G. incrustans, and M. poae. Colony characteristics and growth rate were valuable in presumptively distinguishing most species. For example, O. korrae colonies had distinctively raised or dome-shaped mycelium, whereas O. herpotricha isolates produced a brownish black colored exudate in the center of 2-week-old colonies. Gaeumannomyces graminis var. avenae isolates were separated from G. incrustans and M. poae based on their very slow growth at 30 degrees C. Initially, only single isolate of G. cylindrosporus, G. graminis var. avenae, G. graminis var. graminis, G. incrustans, M. poae, O. herpotricha, O. korrae, and R. graminicola were evaluated against 20 oligonucleotide primers (10-mers) for identifiable and reproducible DNA products