Use of resistant plant varieties combined with other disease management practices is regarded as the most practical approach to control of seedborne bacterial disease agents. In this study, responses of different bean cultivars to nine different races of Pseudomonas syringae pv phaseolicola, the causal agent of bacterial halo blight of common bean (Phaseolus vulgaris L.), were determined. During compatible interaction in susceptible cultivars, virulent bacterial races caused water soaked lesion at sites of inoculation. Similar lesions developed in moderately resistant cultivars but symptoms were later associated with more tissue browning around the sites of inoculation. In contrast, the resistant response, produced the characteristic hypersensitive reaction (HR), was characterized as a small discrete browning and tissue collapse at site of inoculation. No local cultivars showed complete resistance to all races tested. Bean cultivars Sehirali-90 and Göynük-98 were found to be resistant or moderately resistant to five different bacterial races. Bean cultivar, Karacaşehir-90, on the other hand, was found to be resistant or moderately resistant to six different bacterial races. Analysis of bacterial growth and the accumulation of isoflavonoid bean phytoalexin, phaseollin in planta were carried out for tissues expressing compatible and incompatible interactions to enable a link to be made between reaction phenotypes and restriction of bacterial growth and phytoalexin accumulations. Development of the HR was clearly associated with the restricted multiplication of bacteria during incompatible interactions. A time-course accumulation analysis on pods treated with different races of bacterial agent showed that a strong correlation was observed between the timing and extent of cell death and accumulation of phaseollin, being rapid and extensive in incompatible interactions compared to compatible interaction.

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Pomegranate trees were affected by the disease with outgrowths (galls or knot) disease. Currently, there is no published study on disease agent(s) causing the galls or knots on pomegranate trees in worldwide. Bacterial colonies were isolated from young knots. The causal agent of the knot Pseudomonas savastanoi pv.savastanoi (Psv) was identified based on symptoms, biochemical, molecular methods, pathogenicity tests and sequence analysis. To the best of our knowledge, this is the first report of Psv on pomegranate as a natural host, which extends the growing list of plant species affected by this bacterium in the world and Turkey.

Pomegranate (Punica granatum L.) is an increasingly important fruit crop that is widely cultivated in Turkey. Typical bacterial blight symptoms were observed since spring of 2011 in pomegranate orchards located in Antalya Province. Symptoms were characterized by dark brown, angular to irregularly shaped spots on leaves and fruit; cankers on stems, branches, and trunks; and split trunks. The pathogen was isolated from leaf spots on naturally infected plants showing typical symptoms onto yeast dextrose chalk agar. Bright yellow bacterial colonies were consistently isolated. Bacterial strains were characterized as gram negative, oxidase negative, catalase positive, tobacco hypersensitivity positive, and able to produce acid from L-arabinose, D-galactose, D-glucose, and D-mannitol but not from D-xylose. Pathogenicity of the representative bacterial strain Serik-4 was performed on 2-year-old pomegranate plants cv. Hicaz. Leaves were sprayed until runoff with bacterial cell suspensions containing 107 CFU/ml. Inoculated plants were covered with transparent plastic bags to maintain moisture for 48 h. Negative control plants were inoculated with sterile distilled water. Plants were then incubated in a greenhouse at 30°C for 14 days. Symptoms on leaves included dark brown, angular to irregularly shaped water soaked lesions along the veins of the inoculated plants 10 days after inoculation. No lesions developed on the control plants. The symptoms on inoculated plants were similar to those on naturally infected plants. Yellow bacterial colonies were re-isolated from the inoculated plants and identified as the same as the original strain by conventional tests and FAME analysis, thus fulfilling Koch's postulates. Fatty acid methyl ester profiling of the representative strain Serik-4 using GC-MIDI (Microbial Identification Inc, Newark, DE) identified the genus of the bacterium as Xanthomonas. The identity of Serik-4 was further confirmed by amplifying the 16S rRNA gene with the universal primers 27F and 1492R (3) and sequence analysis (GenBank Accession No. KM007073). The 16S rRNA gene sequences of Serik-4 was 99% identical to the corresponding gene sequences of the Xanthomonas axonopodis pv. punicae strain present in the NCBI database (JQ067629.1). High incidence of bacterial blight caused by X. axonopodis pv. punicae on pomegranate has been previously reported in India (2), Pakistan (1), and South Africa (4). To our knowledge, this is the first report of bacterial blight on pomegranate caused by X. axonopodis pv. punicae in Turkey. References: (1) M. A. Akhtar and M. H. R. Bhatti. Pakistan J. Agric. Res. 13:95, 1992. (2) R. Chand and R. Kishun. Indian Phytopathol. 44:370, 1991. (3) D. J. Lane. Page 115 in: Nucleic Acid Techniques in Bacterial Systematics, 1991. (4) Y. Petersen et al. Australas. Plant Pathol. 39:544, 2010.

Since March, 2011, typical leaf spot symptoms were observed on parsley in several fields inspected in Hatay and Adana provinces of Turkey. Incidence of the disease was 5–15% in the regions. Symptoms were characterized as angular to irregular, initially water soaked later brown to dark black spots. Spots often limited by veins which were visible from both adaxial and abaxial sides of leaves but were not present on stems. Fluorescent bacterial colonies were consistently isolated from typical leaf spots. Biochemical tests, fatty acid methyl ester (FAME) analysis, molecular, pathogenicity tests and sequence of 16S ribosomal DNA of bacterial isolates were performed to identify possible causal disease agent. The causal disease agent was identified as Pseudomonas syringae pv. apii based on symptoms, biochemical, molecular, pathogenicity tests and sequencing. To our knowledge, this is the first report of bacterial leaf spot on parsley caused by Pseudomonas syringae pv. apii in Turkey.