S. Chittaranjan et Sh. Deboer, DETECTION OF XANTHOMONAS-CAMPESTRIS PV. PELARGONII IN GERANIUM AND GREENHOUSE NUTRIENT SOLUTION BY SEROLOGICAL AND PCR TECHNIQUES, European journal of plant pathology, 103(6), 1997, pp. 555-563
Specificity of a new monoclonal antibody, 2H5, to Xanthomonas campestr
is pv. pelargonii, causal agent of geranium bacterial blight, was dete
rmined by enzyme-linked immunosorbent assay (ELISA) and immunofluoresc
ence tests on 14 strains of X. c. pelargonii, 12 strains of other X. c
ampestris pathovars, 3 strains of other Xanthomonas spp., 3 strains of
other plant pathogens, and 43 saprophytic bacteria isolated from gera
nium. X. c. pelargonii was detected in tissue from symptomatic and asy
mptomatic geraniums sampled from commercial growers, and artificially
inoculated plants, by monoclonal antibody-based tests. The intensity o
f response in ELISA was only moderately correlated (r = 0.56) with sym
ptom severity, while symptom severity was not correlated (r = 0.16) wi
th the number of fluorescing cells in immunofluorescence. The bimodal
frequency distribution of ELISA and immunofluorescence results served
to validate arbitrarily chosen positive/negative threshold values. Mos
t positive ELISA and immunofluorescence test results were confirmed by
the polymerase chain reaction (PCR) using published primers (Manulis
et al., 1994. Appl. Environ. Microbiol 60, 4094-4099). In contrast to
plant tissue, the bacterium was detected in greenhouse nutrient soluti
on with greater sensitivity by immunofluorescence and PCR than by ELIS
A. Sensitivity of detection was enhanced 100-fold by concentration of
the bacteria by centrifugation.