TABLE 1.

Effects of pretreatments applied to plant extracts on the frequency of detection of X. axonopodis pv. dieffenbachiae by nested PCR

Treatment	Frequency of nested PCR detection (no. of positive samples/no. of samples tested)a
Tris buffer	0/10
PP buffer (2% PVP)	8/10
PP buffer (5% PVP)	10/10
PPP buffer (2% PVPP)b	1/10c
PPP buffer (5% PVPP)	4/10c
TENP buffer (2% PVP)	1/9c
TENP buffer (5% PVP)	9/10c
TENPP buffer (2% PVPP)	2/10c
TENPP buffer (5% PVPP)	4/10c
Positive controld	10/10

^aSuspensions of X. axonopodis pv. dieffenbachiae LMG 695 were added to samples (final concentration, 10⁶ CFU ml⁻¹) containing healthy plant extracts mixed with different buffers (1:1) and were subjected to boiling and nested PCR as described in the text.

^bPVPP, polyvinylpolypyrrolidone.

^cThe signals were weak.

^dLMG 695 suspension in 10 mM Tris buffer (final concentration, 10⁶ CFU ml⁻¹) and no plant extract.