A rapid technique for identification and detection of Phoma sclerotioides, the causal agent of brown root rot of alfalfa, has been developed using polymerase chain reaction (PCR). Amplification products obtained from random amplified polymorphic DNA (RAPD) reactions were cloned and sequenced, and two extended primer sets were designed from the resulting data that were used to detect sequence-characterized DNA markers. A single 499-bp DNA amplification product was consistently obtained from primers PSB12 that was specific for 19 isolates of P.sclerotioides but was not produced from Phoma medicaginis or Phoma betae, or from other soilborne pathogens including Aphanomyces euteiches, Rhizoctonia solani, Fusarium oxysporum, Pythium ultimum, or Phytophthora infestans. A 499-bp amplification product was also produced from root tissue known to be infected with the fungus as verified by microscopic examination. A similar PCR product was obtained from soil samples collected from fields with an established infection of P. sclerotioides on alfalfa. This PCR-based assay enables detection of P. sclerotioides from alfalfa root tissue and in soil samples in a single day, including extraction of DNA, compared with standard methods that require up to 100 days for identification using agar media.
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http://dx.doi.org/10.1094/PDIS.2002.86.9.928 | DOI Listing |
Background: Snow mold caused by different psychrophilic phytopathogenic fungi is a devastating disease of winter cereals. The variability of the snow mold pathocomplex (the quantitative composition of snow mold fungi) has not been evaluated across different crops or different agrocenoses, and no microbial taxa have been predicted at the whole-microbiome level as potential effective snow mold control agents. Our study aimed to assess the variability of the snow mold pathocomplex in different winter cereal crops (rye, wheat, and triticale) in different agrocenoses following the peak disease progression and to arrange a hierarchical list of microbial taxa predicted to be the main candidates to prevent or, conversely, stimulate the development of snow mold pathogens.
View Article and Find Full Text PDFPersoonia
June 2015
State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, No. 3 1st Beichen West Road, Chaoyang District, Beijing 100101, China;
During a survey of cold-adapted fungi in alpine glaciers on the Qinghai-Tibet Plateau, 1 428 fungal isolates were obtained of which 150 species were preliminary identified. Phoma sclerotioides and Pseudogymnoascus pannorum were the most dominant species. Psychrotolerant species in Helotiales (Leotiomycetes, Ascomycota) were studied in more detail as they represented the most commonly encountered group during this investigation.
View Article and Find Full Text PDFStud Mycol
June 2013
CBS-KNAW Fungal Biodiversity Centre, P.O. Box 85167, 3508 AD Utrecht, The Netherlands ; Wageningen University and Research Centre (WUR), Laboratory of Phytopathology, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands.
Unlabelled: The anamorphic genus Phoma was subdivided into nine sections based on morphological characters, and included teleomorphs in Didymella, Leptosphaeria, Pleospora and Mycosphaerella, suggesting the polyphyly of the genus. Recent molecular, phylogenetic studies led to the conclusion that Phoma should be restricted to Didymellaceae. The present study focuses on the taxonomy of excluded Phoma species, currently classified in Phoma sections Plenodomus, Heterospora and Pilosa.
View Article and Find Full Text PDFPhytopathology
May 2011
Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY, USA.
Phoma sclerotioides, causal agent of brown root rot of alfalfa, causes severe root and crown lesions on alfalfa and other perennial forage legumes in regions with harsh winters. Isolates of P. sclerotioides exhibit diverse cultural morphologies on potato dextrose agar (PDA), suggesting that they may exhibit a high degree of genetic diversity.
View Article and Find Full Text PDFPlant Dis
March 2009
Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY 14853.
Brown root rot (BRR), caused by the fungal pathogen Phoma sclerotioides G. Preuss ex Sacc. (synonym Plenodomus meliloti Dearn.
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