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Molecular Pathogens
MP2011, Vol.2, No.3
http://mp.sophiapublisher.com
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Table 4 ELISA detection of bacteria on infected leaf using detached leaf assay
Day after
inoculation
Initial bacteria
density (CFU)
Replication
PCR detection (XAC
specific primers)
Living cell
Dead cell
1
2
3
1
2
3
0
10
5
-
-
-
a
-
-
-
+
10
4
-
-
-
-
-
-
+
10
3
-
-
-
-
-
-
+
2
10
5
+
+
+
+
+
+
+
10
4
- -
-
- -
-
+
10
3
-
-
-
-
-
-
+
4
10
5
+
+
+
+
+
+
+
10
4
-
+
+
+
+
+
+
10
3
-
+
+
+
+
+
+
6
10
5
+
+
+
+
+
+
+
10
4
+
+
+
+
+
+
+
10
3
+
+
+
+
+
+
+
8
10
5
+
+
+
+
+
+
+
10
4
+
+
+
+
+
+
+
10
3
+
+
+
+
+
+
+
10
10
5
+
+
+
+
+
+
+
10
4
+
+
+
+
+
+
+
10
3
+
+
+
+
+
+
+
a: The positive result (+) was indicated when A
405
was greater than twice of the negative control (
-
)
Table 5
Xac
specific amplification of canker pathogen from symptom and non-symptom plant materials
Day after inoculation
No. of plants in plant status
PCR detection(%)
a
Symptom
Non-symptom
Symptom
Non-symptom
Plant materials
10
10
100%
40%
Leaf
6
6
100%
33%
Note: a: [number of sample that can be detect by
Xac
primers/total samples tested]
×
100
2 Conclusion
The sensitivity and specificity of serological and
molecular tools have been investigated. The molecular
tool is more effective than serological tool due to the
high sensitivity (at least 1 cell) and specificity.
Therefore, molecular detection able to detect the
present of pathogen in infected leave even before the
appearance of symptom. However, serological test
from this study was not inferior to other reports and
sufficient for pathogen detection from symptomatic
tissue.
3 Materials and Methods
3.1 Isolation of
Xanthomonas axonopodis
pv.
citri
(
Xac
)
Infected lime leaves from three different regions in
Thailand; Samut Sakhon, Nakhon Ratchasima and
Phichit which are about 300~500 km apart were used
in this study. Different
Xac
isolates were isolated from