A novel Bacteroidetes symbiont is localized in Scaphoideus titanus, the insect vector of Flavescence dorée in Vitis vinifera.
Flavescence dorée (FD) is a grapevine disease that afflicts several wine production areas in Europe, from Portugal to Serbia. FD is caused by a bacterium, "Candidatus Phytoplasma vitis," which is spread throughout the vineyards by a leafhopper, Scaphoideus titanus (Cicadellidae). After collection of S. titanus specimens from FD-contaminated vineyards in three different areas in the Piedmont region of Italy, we performed a survey to characterize the bacterial microflora associated with this insect. Using length heterogeneity PCR with universal primers for bacteria we identified a major peak associated with almost all of the individuals examined (both males and females). Characterization by denaturing gradient gel electrophoresis confirmed the presence of a major band that, after sequencing, showed a 97 to 99% identity with Bacteroidetes symbionts of the "Candidatus Cardinium hertigii" group. In addition, electron microscopy of tissues of S. titanus fed for 3 months on phytoplasma-infected grapevine plants showed bacterial cells with the typical morphology of "Ca. Cardinium hertigii." This endosymbiont, tentatively designated ST1-C, was found in the cytoplasm of previtellogenic and vitellogenic ovarian cells, in the follicle cells, and in the fat body and salivary glands. In addition, cell morphologies resembling those of "Ca. Phytoplasma vitis" were detected in the midgut, and specific PCR assays indicated the presence of the phytoplasma in the gut, fat body and salivary glands. These results indicate that ST1-C and "Ca. Phytoplasma vitis" have a complex life cycle in the body of S. titanus and are colocalized in different organs and tissues.
Marzorati
Massimo
M
Dipartimento di Scienze e Tecnologie Alimentari e Microbiologiche, Università degli Studi di Milano, 20133 Milan, Italy.
Alma
Alberto
A
Sacchi
Luciano
L
Pajoro
Massimo
M
Palermo
Simona
S
Brusetti
Lorenzo
L
Raddadi
Noura
N
Balloi
Annalisa
A
Tedeschi
Rosemarie
R
Clementi
Emanuela
E
Corona
Silvia
S
Quaglino
Fabio
F
Bianco
Piero Attilio
PA
Beninati
Tiziana
T
Bandi
Claudio
C
Daffonchio
Daniele
D
D000818:Animals; D041963:Bacteroidetes / Q000235:genetics / Q000302:isolation & purification* / Q000472:pathogenicity / Q000648:ultrastructure; D001483:Base Sequence; D004269:DNA, Bacterial / Q000235:genetics; D005216:Fat Body / Q000382:microbiology / Q000648:ultrastructure; D005260:Female; D006430:Hemiptera / Q000382:microbiology* / Q000648:ultrastructure; D007303:Insect Vectors / Q000382:microbiology* / Q000648:ultrastructure; D008297:Male; D008854:Microscopy, Electron; D008969:Molecular Sequence Data; D010053:Ovary / Q000382:microbiology / Q000648:ultrastructure; D010802:Phylogeny; D010935:Plant Diseases / Q000382:microbiology* / Q000469:parasitology*; D012469:Salivary Glands / Q000382:microbiology / Q000648:ultrastructure; D013559:Symbiosis; D027843:Vitis / Q000382:microbiology* / Q000469:parasitology*
D004269:DNA, Bacterial