Identification of Flavescence dorée-related phytoplasma infecting grapevines on the isle of Ischia (southern Italy)

Among the grapevine diseases, Flavescence dorée (FD) is considered to be one of the greatest threats for grapevine cultivation throughout Europe. In Italy, where several major outbreaks of FD have occurred in the past, the disease is still mainly restricted to the northern regions and is under mandatory regulation. In 2011 the disease was recorded for the first time in southern Italy, in several vineyards located on the isle of Ischia (Campania). In order to determine the FD-related phytoplasma infecting these grapevines, molecular investigations were carried out on grapevine samples collected from several FD infected vineyards. The 16S rDNA/spacer region and the FD9 non-ribosomal fragment (secY gene) were investigated using a PCR/RFLP based method; a nucleotide sequence analysis of the FD9 amplified fragments was also carried out. The RFLP profiles obtained from all the analyzed samples showed the presence of FD-D phytoplasma type, on both 16S and secY genomic regions. Sequencing of the FD9 fragments showed a 99 % nucleotide sequence identity among the tested isolates and the various FD-D strains retrieved from the NCBI database.

Detection of Tumorigenic Rhizobia in Asymptomatic Peach Plants by PCR

At present the only method for the detection of Rhizobium radiobacter and R. rhizogenes (ex Agrobacterium tumefaciens) in plants is by isolating the bacteria on selective medium and testing them in vivo for pathogenicity. This procedure is time-consuming and not appropriate for detecting low concentrations of these agrobacteria. In this study a protocol was developed for detecting tumorigenic agrobacteria in the stem and root tissues of artificially inoculated peach plants. DNA was extracted from the plant tissues by a rapid procedure and then a 246 bp sequence of the vir region of the pTi was amplified by PCR. The target sequence was found in all stem and root samples of asymptomatic peach plants, and was evidenced in all the samples analyzed showing the effectiveness and reliability of the method

Plant Dynamic Metabolic Response to Bacteriophage Treatment After Xanthomonas campestris pv. campestris Infection

Periodic epidemics of black rot disease occur worldwide causing substantial yield losses. Xanthomonas campestris pv. campestris (Xcc) represents one of the most common bacteria able to cause the above disease in cruciferous plants such as broccoli, cabbage, cauliflower, and Arabidopsis thaliana. In agriculture, several strategies are being developed to contain the Xanthomonas infection. The use of bacteriophages could represent a valid and efficient approach to overcome this widespread phenomenon. Several studies have highlighted the potential usefulness of implementing phage therapy to control plant diseases as well as Xcc infection. In the present study, we characterized the effect of a lytic phage on the plant Brassica oleracea var. gongylodes infected with Xcc and, for the first time, the correlated plant metabolic response. The results highlighted the potential benefits of bacteriophages: reduction of bacterium proliferation, alteration of the biofilm structure and/or modulation of the plant metabolism and defense response