First report of a phytoplasma associated with Bermudagrass white leaf disease in Cuba

Bermudagrass (Cynodon dactylon) is an invasive, noxious weed of pasture and cultivated land in the tropics and subtropics. White leaf of Bermudagrass (BGWL), caused by a phytoplasma belonging to the 16SrXIV group, has been reported from many countries on the continents of Asia (Lee et al, 1997), Europe (Marcone et al, 2004) and Africa (Cronjé et al, 2000). Until now it has not been reported from Latin America or the Caribbean. Leaf samples from 13 Bermudagrass plants showing typical BGWL symptoms and from six apparently healthy (symptomless) plants were collected during a survey of graminaceous weeds from fields growing sugarcane in Güines, Havana Province, Cuba. DNA was extracted and assayed in a nested PCR with phytoplasma universal rDNA primers P1/P7 and R16F2n/R16R2. All 13 DNA extracts from plants with white leaf produced products of 1250 bp, which gave typical phytoplasma profiles when digested with HaeIII. No PCR amplifications were produced using DNA from symptomless plants. RFLP analysis of PCR products with HaeIII, RsaI or AluI endonuclease generated fragment profiles that were identical for all white leaf samples. The phytoplasma 16/23S intergenic region was sequenced directly with primers P4 and P7 and compared by BLAST analysis with those of other phytoplasma rDNA sequences archived in GenBank. The highest sequence homology (95%) obtained was with that of 'Candidatus Phytoplasma cynodontis' (GenBank Accession No.Y14645), the type member of the BGWL (16SrXIV) group. The sequence obtained from the Cuban phytoplasma was deposited in the GenBank database (Accession No. AY725238). This is the first record of Bermudagrass white leaf disease in Cuba and its association with a phytoplasma.