Improved immunological detection of Spongospora subterranea

• Published in: European journal of plant pathology 2005-04, Vol.111 (4), p.371-379
• Main Authors: Merz, U, Walsh, J.A, Bouchek-Mechiche, K, Oberhansli, T, Bitterlin, W
• Format: Article
• Language: English
• Subjects: Bacterial plant pathogens; Biological and medical sciences; cross reaction; cystosori; diagnostic techniques; Disease control; disease detection; Fundamental and applied biological sciences. Psychology; fungal anatomy; immunologic techniques; Immunology; Life Sciences; monoclonal antibodies; Nasturtium officinale; new methods; Pathogens; Phytopathology. Animal pests. Plant and forest protection; Plant diseases; Plant pathology; Plant resistance; Plasmodiophora; Plasmodiophoromycetes; Polymyxa; Potatoes; scab diseases; Solanum tuberosum; Spongospora subterranea; strain differences; strains; Vegetal Biology; watercress
• ISSN: 0929-1873; 1573-8469
• DOI: 10.1007/s10658-004-6330-7

The genus Spongospora has two members which are important pathogens of vegetables, S. subterranea f.sp. subterranea (Sss) and S. subterranea f.sp. nasturtii (Ssn). The close taxonomic relationship of these formae speciales is based on similar cystosori morphology. The potato disease powdery scab, caused by Sss, is difficult to control. The key control measure is avoidance, aimed at planting clean seed in clean soil. For the development of routine tests for the presence of the pathogen on tubers and in soil, a monoclonal antibody (MAb) was developed using Sss cystosori as immunogen. It detected less than one Sss cystosorus and recognised Sss material from many parts of the world. No cross-reactions with other Plasmodiophoromycetes including Plasmodiophora brassicae, Polymyxa betae, Polymyxa graminis and different Streptomyces species causing common and netted scab of potatoes were observed. A novel tuber sample test method was developed using a kitchen peeling machine. This detected two tubers with one powdery scab lesion each in a sample including eighteen uninfected tubers. When soil samples spiked with cystosori were tested with the MAb, different Sss infestation levels could be discriminated. Ssn cystosori gave absorbance values in ELISA as high as Sss cystosori, whereas fresh crook roots of watercress containing Ssnzoosporangia and plasmodia or mud from an Ssninfected watercress bed gave low absorbance values or no reaction. The potential of these findings for the development of a disease control management are discussed.