Fifty-six tumorigenic Spanish grapevine strains of Agrobacterium spp. were tested for biovar classification, pathogenicity on several hosts, opine utilization, 16S rRNA gene sequencing and PCR amplifications using five primer sets targeting chromosomal and Ti plasmid genes. Fifty of them belonged to A. vitis (biovar 3), three to A. tumefaciens (biovar 1) and three to A. rhizogenes (biovar 2). All strains were tumorigenic on grapevines. Most A. vitis strains were also pathogenic on tomato and tobacco plants, while the three A. tumefaciens strains were only pathogenic on grapevine. Although most A. vitis strains used octopine, 12 utilized neither octopine nor nopaline. 16S rRNA gene sequencing clearly distinguished between strains belonging to the three species. Those of A. vitis could be further divided into three chromosomal backgrounds according to their 16S ribosomal RNA gene sequences. No universal primer pair was found for the detection of all three Agrobacterium species isolated from grapevine. DNA from all A. vitis strains was amplified with the chromosomally-encoded pehA primer pair. In both A. vitis and A. tumefaciens a correlation was observed between the amplifications obtained using the tmr and the virA Ti-plasmid-targeting primer pairs. Three types of Ti plasmid were found in A. vitis strains according to their PCR amplifications and opine utilization profiles. A given chromosomal background harboured only one type of Ti plasmid within the strains from each analysed sample, showing a strong association between chromosomal backgrounds and Ti plasmids in A. vitis .

In 2006, a serious outbreak of bacterial leaf and flower spot disease was observed on zinnia ( Zinnia elegans ) cvs Capricio and Mondo) grown in several parks in Budapest, Hungary. The disease first appeared on leaves as diffuse, translucent, circular spots surrounded by large chlorotic haloes. The lesions enlarged and became reddish brown in the centre and angular in shape. On the flowers, at high humidity, small brown spots appeared, and the flower heads were disfigured and decayed completely. Bacteria were isolated on modified Tween medium (Schaad et al ., 2001). All isolates were Gram-negative rods, aerobic, and produced yellow, xanthomonadin pigments identified by thin-layer chromatography (Schaad et al ., 2001). Isolates were positive for catalase, negative for oxidase, hydrolised starch, gelatine, casein, and aesculin; hydrogen sulphide was produced from cysteine. In medium C of Dye (Dye, 1968) acids were produced from arabinose, glucose, maltose and sucrose, but not from sorbitol. The sequence of the 16S-23S rDNA spacer region of the bacterial strain (GenBank Accession No. EF514223) was determined. The sequence shared 99·7% identity with other X. campestris pv . zinniae strains available in GenBank.Pathogenicity was confirmed by artificial inoculation of healthy, four to six-leaf stage zinnia plants with a suspension of an isolated bacterial strain (1 × 10 7 CFU per mL). Sterile distilled water was used as a negative control. The inoculated plants were incubated in a mist chamber (95% relative humidity) for 3 days, and then transferred to a greenhouse at 21-27 ° C. Characteristic leaf spot symptoms were observed on inoculated zinnia plants 8 days after inoculation. No symptoms were observed on control plants. The original pathogen strain was reisolated from diseased leaves.Bacterial leaf spot of zinnia was first reported in 1929, in Italy (Nanizzi, 1929), and the pathogen was named later as X. campestris pv. zinniae (Dye, 1978). Since 1929 no report describing the disease has been published in Europe. This is the first report on the occurrence of this bacterium on zinnia in Hungary. Agrobacterium -like colonies were recovered from New and Kerr's medium from a crown gall of grapevine rootstock 41B ( Vitis vinifera × V. berlandieri ) from a nursery located in Badajoz province. After colony purification and tomato and tobacco plant inoculations, three Agrobacterium isolates, tumorigenic in both plant species, were characterized. On the basis of biovar classification, all isolates were identified as belonging to biovar 2 of Agrobacterium (also called A. rhizogenes ). Because this biovar is not common in grapevine, all isolates were also inoculated onto grapevine plants of cv. Tempranillo, which developed typical tumors one-month after inoculations. DNA from all isolates yielded the expected amplification product when using FGP tmr 530-FGP tmr 701', vir B/G and VCF/VCR primer sets (Cubero et al ., 1999), confirming their pathogenic nature, but not when using virA or pehA primer sets (Eastwell et al ., 1995), ...