Quantitative PCR assay for detection of bois noir phytoplasmas in grape and insect tissue

; ; (). Quantitative PCR assay for detection of bois noir phytoplasmas in grape and insect tissue. Vitis, 52, 2. 85-89. Peer reviewed.

In Europe's vineyards "Bois noir" (BN) is an expanding
yellows disease on Vitis vinifera. It is associated
with phytoplasmas of the stolbur group (16SrXII-A).
Two subtypes are important, one is associated with
Urtica dioica and one with Convolvulus arvensis. Both
phytoplasma types are transmitted by the insect Hyalesthes
obsoletus
. A nucleic acid extraction method for
V. vinifera and H. obsoletus was developed together with
a real time PCR (qPCR) assay based on a polymorphic
sequence with homology to a putative dimethyladenosine
transferase. The comparison of the conventional
detection method with the qPCR assay of 40 insect and
40 V. vinifera samples showed a 10 % higher sensitivity
of qPCR in plant samples. The titer of phytoplasmas
in H. obsoletus was 2643-fold increased in the strongest
infected samples compared to the lowest ones.
The results suggest this real-time PCR as a valid
and fast alternative procedure for the detection and
quantification of BN phytoplasmas. The assay allows to
discriminate the two phytoplasma types and to quantify
phytoplasmas in H. obsoletus.