Archivio Journal of Plant Pathology

Abstract:

Potato (Solanum tuberosum), one of the most important crops worldwide, is susceptible to a high number of viruses and phytoplasmas. During the summer of 2013 symptoms similar to those caused by phytoplasmas, such as dwarfing, bright red discoloration, and rolling of the top leaves were observed in potato crops of cvs. Spunta and Jelly in Kastoria (40° 31'0 .12 "N21° 16'0 .12" E), Northern Greece. The affected plants were scattered in the field and their incidence ranged among the plots between 10% and 20%. In order to investigate the etiology of the aforementioned symptoms, leaves from 10 symptomatic and 10 asymptomatic plants of each variety were collected and subjected to DNA extraction. The extracts were tested using a generic nested PCR that targets the highly conserved 16S rRNA gene of phytoplasmas. More specifically, the universal primer set P1/P7 (Schneider et al., 1995) was used in the first round of PCR, whereas R16F2n/R16R2 primers (Gundersen and Lee, 1996) were applied in the nested step. The expected PCR products of ca. 1200 bp were amplified from all samples coming from symptomatic plants but not from the asymptomatic ones. One amplicon from each variety was further sequenced in both directions and their BLAST analysis revealed 98% similarity with the sequences of several “Candidatus Phytoplasma solani” (16SrXII-A stolbur group) strains (e.g. Bulgarian strain 241/13, KF907506). The two Greek sequences were 99% similar between them and were deposited in the EMBL-EBI under the accession Nos HG531809 and HG792592. “Ca. Phytoplasma solani” is endemic in Greece and was first detected in Datura stramonium plants in the area of Thessaloniki (Macedonia, Northern Greece). However, this is to our knowledge the first report of a potato disease caused by a “Ca. Phytoplasma solani” related strain in our country.