First report of a 16SrIII phytoplasma (X-disease group) affecting bell pepper, strawberry (frutilla), Schinus molle and Arracacia xanthorrhiza in Cochabamba, Bolivia

Bell pepper (Capsicum annuum) and strawberry (Fragaria chiloensis, ‘frutilla’ in Spanish) are crops grown for local consumption in plots at the PROINPA Foundation, Cochabamba. Schinus molle (family Anacardiaceae, known locally as ‘molle’) is an ornamental tree widely distributed in Cochabamba urban areas, including PROINPA surroundings. Recently, symptoms of leaf size reduction and yellowing, proliferation, and shortening of internodes were observed in S. molle trees (Fig. 1). Strawberry plants displayed rosette formation and small fruits, while bell pepper showed leaf size reduction and shortening of internodes (Fig. 2). Symptoms were present in about 30% of strawberry and bell pepper plots, and more than 50% of the S. molle trees surrounding PROINPA exhibited symptoms. Arracacia xanthorrhiza, a nearby-grown vegetable in the celery family (Apiaceae), displayed leaf yellowing and little leaf. Symptom-bearing plants of bell pepper (4), S. molle (5), strawberry (4) and A. xanthorrhiza (4) were collected, as well as one symptomless plant of each plant species. Total DNA from leaf midribs was extracted and indexed by a nested PCR with universal 16S rRNA primers R16mF2/R1 and fU5/rU3. PCR amplicons (approximately880 bp) were produced for almost all symptom-bearing plants, except for one plant of strawberry and one plant of A. xanthorrhiza. Symptomless plants did not yield amplicons. PCR amplicons were purified (Wizard, Promega), cloned (pGEMT-Easy Vector, Promega) and sequenced (http: www.dnaseq.co.uk). The 16S rRNA sequences of phytoplasmas detected in bell pepper (GenBank Accession No. FJ207456), strawberry (FJ207455), S. molle (FJ207454) and A. xanthorrhiza (FJ207451) showed the highest identity of 99% with the members of phytoplasma group 16SrIII (X-disease). A 16SrIII phytoplasma has been previously reported in Bolivia affecting chinaberry (Melia azadarach) trees (Harrison et al., 2003). To our knowledge, this is the first report of phytoplasmas belonging to group 16SrIII in bell pepper, strawberry, S. molle, and A. xanthorrhizain Cochabamba, Bolivia.