Immuno-capture of Ralstonia solanacearum by an EPS-specific monoclonal antibody enhances sensitivity of PCR.
G. D. PECKHAM (1), M. A. Schell (2), J. Kim (2), J. M. Berestecky (3), A. M. Alvarez (1) (1) University of Hawaii, Honolulu, HI, USA; (2) University of Georgia, Athens, GA, USA; (3) Kapiolani Community College, Honolulu, HI, USA.
Phytopathology 99:S101.

Abstract: Detection of Ralstonia solanacearum (Rs) in field soil and irrigation water is complicated by significant heterogeneity within the species complex and insufficient bacterial populations for most detection assays. DNA-based methods, though sensitive and specific, are not very practical since it only accommodates a small sample volume, usually 1–5 microliters, which may not contain enough bacterial DNA for detection. Therefore, an anti-Rs antibody was developed with the aim of concentrating dilute populations of bacteria from large volumes of irrigation or drainage water. The antibody was developed using traditional monoclonal hybridoma technology with a pool of 10 Rs strains as the antigen. The strong reacting antibody 3.H7 (IgG3 with kappa light chain) is specific for all Rs EPS (109 strains from diverse hosts and geographical origins, representing 3 phylotypes) with only one exception (one BDB strain from banana). Detection of dilute concentrations of Rs was not possible when aliquots of large water samples were directly added to PCR reactions (using fliC or 759/760 primers); however, aliquots of 3.H7-immuno-captured cells were successfully amplified by PCR from these same water samples.