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First Report of Erwinia persicina from Phaseolus vulgaris in Spain

A previously unreported leaf spot disease of common bean, which caused losses as much as 50% of the crops, was observed in southeastern Spain (Almería, Granada, and Málaga provinces) in November 2003. In 2004, samples of cv. Donna with chlorotic and necrotic leaf spots were collected from Granada and processed for microbiological analysis. Bacteria isolated from the symptomatic leaves were determined to be fermentative on the basis of the ability to metabolize glucose in aerobic and anaerobic conditions. Three isolates were selected for pathogenicity tests. Bacterial suspensions (10⁸ CFU/ml) were spray inoculated on bean seedlings (3 true leaves) of cv. Andecha. Beans were covered with transparent plastic bags for 2 days and held in an incubation chamber at 22°C and 80% relative humidity with a 12-h photoperiod. Assays were repeated at least twice. Symptoms that developed on plants inoculated with the three isolates were similar to those originally observed, while symptoms did not occur on control plants (inoculated with distilled water). The pathogenic isolates were identified by sequencing of the 16S rDNA after amplification (2). The amplified sequences were compared to available DNA sequences in databases by using BLAST (1); 99% homology with 16S rDNA of Erwinia persicina was shown. Microbiological characteristics (gram staining, motility, morphology, and results of biochemical tests) were in agreement with the molecular identification of the isolates. E. persicina has been isolated from bean in the United States (4) and described on tomato, banana, and cucumber in Japan (3). To our knowledge, this is the first report of E. persicina from common bean in Spain and in Europe.

References: (1) S. F. Altschul et al. J. Mol. Biol. 215:403, 1990. (2) U. Edwards et al. Nucleic Acids Res. 17:7843, 1989. (3) M. V. Hao et al. Int. J. Syst. Bacteriol. 40:379, 1990. (4) M. L. Schuster et al. Fitopatol. Bras. 6:345, 1981.