Diseases and Management of Crops under Protected Cultivation

(Diseases and Management of Crops under Protected Cultivation)
this assay to the screening of the infected plant materials and seeds. The results indicate that antitomato
R. solonacearum (i) has a good antibody titre of 1:10000 (ii) can detect a few as
100bacterial cells /ml (iii is tomato specific (it reached with tomato R. solonacearum and not
isolates from chilly (Capsicum) or brinjal (iv)is reactive to all isolates of R. solonacearum from
tomato (v)is not cross –reactive with non- pseudomonades (vi) is virulent strain specific as it
recognizes the virulent exopolysaccharides component an anti-determinants (vii) reactivity could
be correlated well with the degree of infection in tomato seeds and plant materials . Thus ELISA
developed is sensitive, specific and rapid, therefore, suitable for detection of R.solanacearum
isolates from tomato seeds during routine assays
Enrichment- ELISA Protocol
In this method, ELISA Protocol, specific monoclonal antibody is used, with prior enrichment
of stem greatly, which improves the sensitivity of detection of bacterial pathogens. It is effective
because of low sensitivity of ELISA for bacterial detection using specific monoclonal antibodies
approximately 105 -106 cfu/ml) and need to improve this sensitivity to detect latent infections of
quarantine bacteria. The use of an optimized enrichment for each plant pathogenic bacterium
allows its specific multiplication in the sample before detection. Specific protocol is required R.
solanacearum (Caruso et al., 2002). The medium temperature, duration and incubation conditions
of the enrichment are crucial for optimizing it and improve the detection sensitivity.
On site testing: tissue print- ELISA and lateral flow devices
A simple method is required for rapid detection of plant pathogenic bacteria for testing
large number of samples by non- experienced technicians. For this purpose, tissue print ELISA
and lateral flow devices have been designed for bacteria. Although detection specificity is very
high when using the appropriate monoclonal antibodies. The sensitivity is low for detecting
bacteria and they are more appropriate for analyzing plants with symptoms. The lateral flow
devices kits are based on existing technology similar to a pregnancy test kit and such kits are only
available for few bacteria. A lateral flow device kit developed by Central Science Laboratory, U.
K., permits detection of R. solanacearum in 3 min, in single step. Rapid ImmunoStrip ® is available
from Agdia Inc. Immunofluorescence. This technique is widely used in Europe for detection of
bacterial pathogens in seed and preparative materials. It is used to screen 60,000 potato pieces
annually for the presence of R. solanacearum (Danks and Baker, 2000; Van der Wolf and Schoen,
2004).
Flow Cytometry
Immunodiagnostic detection has been enhanced by the development of flow cytometry. It
can be used for identification and quantification of cells or other particles as they pass individually
through a sensor in a liquid stream. Cells are identified by fluorescent dyes conjugated to specific
antibodies and multiples cellular parameters are determined simultaneously based on the cells,s
fluorescence and its ability to scatter light. The cells may be sorted electronically, permitting
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