Detection of the sour-rot pathogen Geotrichum candidum in tomato fruit and juice by using a highly specific monoclonal antibody-based ELISA.
Geotrichum candidum is a common soil-borne fungus that causes sour-rot of tomatoes, citrus fruits and vegetables, and is a major contaminant on tomato processing equipment. The aim of this work was to produce a monoclonal antibody and diagnostic assay for its detection in tomato fruit and juice. Using hybridoma technology, a cell line (FE10) was generated that produced a monoclonal antibody belonging to the immunoglobulin class M (IgM) that was specific to G. candidum and the closely related teleomorphic species Galactomyces geotrichum and anamorphic species Geotrichum europaeum and Geotrichum pseudocandidum in the G. geotrichum/G. candidum complex. The MAb did not cross-react with a wide range of unrelated fungi, including some likely to be encountered during crop production and processing. The MAb binds to an immunodominant high molecular mass (> 200 kDa) extracellular polysaccharide antigen that is present on the surface of arthroconidia and hyphae of G. candidum. The MAb was used in a highly specific enzyme-linked immunosorbent assay (ELISA) to accurately detect the fungus in infected tomato fruit and juice. Specificity of the ELISA was confirmed by sequencing of the internally transcribed spacer (ITS) 1-5.8S-ITS2 rRNA-encoding regions of fungi isolated from naturally-infected tomatoes.
Thornton
Christopher R
CR
University of Exeter, Exeter, United Kingdom. C.R.Thornton@ex.ac.uk
Slaughter
David C
DC
Davis
R Michael
RM
D000818:Animals; D000911:Antibodies, Monoclonal; D000918:Antibody Specificity; D001628:Beverages / Q000382:microbiology*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D005516:Food Microbiology; D005638:Fruit / Q000382:microbiology*; D005848:Geotrichum / Q000302:isolation & purification*; D018551:Solanum lycopersicum / Q000382:microbiology*; D051379:Mice; D008807:Mice, Inbred BALB C
D000911:Antibodies, Monoclonal